Test Bank For Advanced Nutrition and Human Metabolism 8th Edition by Sareen Gropper, Jack Smith, Tim

TEST BANK ADVANCED NUTRITION AND HUMAN METABOLISM 8TH EDITION BY SAREEN GROPPER, JACK SMITH, TIMOTHY CAR Chapter 01: The Cell: A Microcosm of Life

Indicate the answer choice that best completes the statement or answers the question.

1. Membrane lipid bilayers consist primarily of a. phospholipids b. cholesterol c. proteins d. saturated fatty acids e. enzymes

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2. Which of the following is a common function of membrane proteins? a. receptors b. detoxifiers c. purifier d. neutron transporter e. storage proteins 3. What is the role of cholesterol in plasma membrane structure? a. to produce bile b. to regulate fluidity and permeability c. to reduce stability d. to produce hormones e. to catalyze chemical reactions 4. Which of the following is not a usual function of the cytoskeleton? a. locomotion b. generation of ATP c. structural support d. positioning of organelles e. transfer of DNA and RNA 5. Which cellular component enables signal transmission to various parts of the cell due to interconnections within the cytosol? a. glycoproteins b. microfilaments c. glycolipids d. integral proteins e. nucleic acids 6. How are the carbohydrate moieties of the plasma membrane glycoproteins and glycolipids oriented?

a. outwardly, away from the cytoplasmic matrix b. inwardly, toward the lumen

c. equally inwardly and outwardly to maintain symmetry

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Chapter 01: The Cell: A Microcosm of Life d. between the bilayers of the membranes e. interlinked with each on both sides of the membrane 7. Which of the following describes proteins attached to the membrane through hydrophobic interactions and embedded in the membrane? a. peripheral proteins b. rough endoplasmic reticula c. integral proteins d. Golgi apparatus e. apoproteins 8. Which structure in the cell provides support and controls the movement of cell organelles? a. endoplasmic reticulum b. mitochondrion c. cytoskeleton d. cytosolic matrix e. nucleus 9. Cytochalasin is a fungal toxin that prevents the polymerization of actin. Which cellular structure is the target? a. nucleus b. cytoskeleton c. lysosomes d. mitochondria e. plasma membrane 10. Which of the following is not normally found in the cytoplasmic matrix of a typical cell? a. amino acids b. glucose-6-phosphate c. carbon dioxide d. urea e. lipids 11. Enzymes of which metabolic pathway can be found in the cytoplasmic matrix? a. beta-oxidation b. glycolysis c. ketone production d. the Kreb’s cycle e. cholesterol synthesis 12. Which organelle is responsible for the production of most of the metabolic energy (ATP)? a. Golgi apparatus b. endoplasmic reticulum

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Chapter 01: The Cell: A Microcosm of Life c. nucleus d. mitochondrion e. lysosome 13. Which of the following can freely diffuse across the inner mitochondrial membrane? a. glucose b. oxygen and carbon dioxide c. fatty acids d. NADH e. protons 14. Where are the majority of the components of the electron transport chain embedded? a. mitochondrial inner membrane b. mitochondrial outer membrane c. mitochondrial matrix d. cytoplasmic matrix e. plasma membrane 15. In which organelle do the TCA cycle and fatty acid oxidation occur? a. Golgi apparatus b. nucleus c. microsomes d. mitochondrion e. endoplasmic reticulum 16. What is the major route for ATP production in the cell? a. oxidative phosphorylation b. hydrolysis c. peroxidation d. transformation e. substrate-level phosphorylation 17. Which organelle is capable of performing both fission and fusion? a. Golgi apparatus b. mitochondria c. rough endoplasmic reticulum d. nucleus e. lysosome 18. What do the genes contained in the mitochondrial DNA code for? a. all proteins functioning within the mitochondrial matrix b. nonfunctional ancient proteins considered remnants of evolution

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Chapter 01: The Cell: A Microcosm of Life c. proteins vital to the production of ATP d. antioxidant proteins e. immune proteins 19. Which cell organelle is responsible for the initiation and regulation of most cellular activity? a. peroxisome b. nucleus c. mitochondrion d. Golgi body e. endoplasmic reticulum 20. In addition to the mitochondria, which organelle possesses an inner and outer membrane? a. lysosome b. peroxisome c. Golgi apparatus d. nucleus e. endoplasmic reticulum 21. Microtubule organization centers (MTOCs) on the outer nuclear membrane are associated with which cellular process? a. oxidative phosphorylation b. electron transport c. mitosis d. protein synthesis e. lipid synthesis 22. What information does the DNA in the nucleus contain? a. the entire genome for that organism b. the genes coding for proteins needed only by that particular cell c. chromatin d. all components of the cytoskeleton e. components of the electron transport chain 23. What is the DNA in the nucleus found wrapped around? a. proteins called histones b. the nucleolus c. the nuclear envelope d. ribosomal RNA e. the inner membrane 24. What is the best description of transcription? a. the genetic information in a single strand of DNA is copied onto a specific sequence of bases in a messenger

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Chapter 01: The Cell: A Microcosm of Life RNA (mRNA) chain b. genetic information in an mRNA molecule specifies the sequence of amino acids in the protein product c. amino acids are linked together to form the primary structure of a protein d. the information of one DNA strand is copied onto another DNA strand e. the primary structure of a protein is folded several times to become the quaternary structure 25. What is the best description of translation? a. the genetic information (base sequence) in a single strand of DNA is used to specify a complementary sequence of bases in an mRNA chain b. a daughter duplex DNA molecule that is identical to the parental duplex DNA is synthesized c. the polypeptide chain is degraded d. information in an mRNA molecule is used to build a sequence of amino acids to form the protein product e. mRNA strand is modified in the nucleus 26. What is the best description of elongation? a. the mRNA strand is formed b. peptide bonds are formed between aligned amino acids after the amino acids are positioned c. amino acids are activated by ATP at their carboxyl end d. activated amino acids are transferred to their specific tRNAs that contain the anticodon complementary to each amino acid’s codon e. amino acids are activated by ATP at their amino terminal end 27. What are the microtubule organization centers (MTOCs) at the outer nuclear membrane composed of? a. sugars b. proteins c. fatty acids d. NADH e. glycolipids 28. What is the role of transcription-level control mechanisms? a. to determine the path by which mRNA can be translated into a polypeptide b. to determine whether a particular mRNA is actually translated c. to determine the effect on the transcription of a gene d. to drive the interaction between tRNA and mRNA e. to drive the interaction between mRNA and RNA Polymerase 29. What are microRNAs? a. small noncoding RNAs that enhance gene expression by activating mRNA expression b. small noncoding RNAs that silence gene expression by binding to mRNA to inhibit translation c. small noncoding RNAs that modify gene expression by replacing specific nucleotides in mRNA d. small noncoding RNAs that mediate DNA production in a reverse direction e. small noncoding RNAs that enhance the interaction between DNA and DNA binding proteins

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Chapter 01: The Cell: A Microcosm of Life 30. What are defined as the nucleotide sequences that are part of a gene but do not code for the protein product? a. exons b. introns c. histones d. promoters e. enhancers 31. Which organelle is composed of an extensive network of membranous channels that connects the nuclear membrane, the Golgi apparatus, and the plasma membrane? a. the lysosome b. the nucleolus c. the centrioles d. the endoplasmic reticulum e. centrosome 32. What is the smooth endoplasmic reticulum (SER) associated with? a. lipid synthesis b. protein synthesis c. the calcium ion pump necessary for the contractile process d. ribosomes and cytochrome P450 enzymes e. production of glycoproteins 33. Which enzyme complex, used in metabolizing many drugs, is located on the rough endoplasmic reticulum in liver cells? a. chromatins b. lysozymes c. cytochromes d. polymerases e. hydrolases 34. What cellular structure is made up of flattened cisternae flanked by tubular networks and thought to be an extension of the endoplasmic reticulum? a. nucleus b. cytoplasm c. lysosome d. Golgi apparatus e. mitochondrion 35. What is the prominent function of the Golgi apparatus in neurons and secretory cells? a. to stop the synthesis of proteins that may need carbohydrate additions b. to add polysaccharide or lipid moieties to modify polypeptides

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Chapter 01: The Cell: A Microcosm of Life c. to regulate the constitutive secretion of proteins d. to inhibit the regulated secretion of proteins e. to synthesize polypeptides from mRNA 36. Which organelle is involved in maintaining quality control of synthesized proteins in the cell? a. the endoplasmic reticulum b. the Golgi apparatus c. the nucleus d. the mitochondrion e. the lysosome 37. Which organelle serves as the digestive system for the cell? a. polysome b. endosome c. lysosome d. ribosome e. liposome 38. Which organelle is involved in detoxification by oxidizing molecules such as hydrogen peroxide and ethanol? a. peroxisome b. endosome c. lysosome d. ribosome e. polysome 39. Destruction of which organelle(s) would cause the cell to cease to function due to a total loss of energy? a. the nucleus b. the Golgi apparatus c. the ribosomes d. the mitochondria e. the lysosomes 40. Pancreatic cells produce many digestive enzymes necessary for digestion in the small intestine. Which organelle(s) is/are necessary for the delivery of digestive enzymes by the pancreatic cells? a. endoplasmic reticulum and Golgi apparatus b. lysosomes c. ribosomes d. peroxisomes e. cytoplasm 41. Damage to MTOCs will interfere with which cellular process? a. oxidative phosphorylation

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Chapter 01: The Cell: A Microcosm of Life b. mitosis c. electron transport d. synthesis of an mRNA molecule e. synthesis of DNA 42. What are the molecular stimuli that bind specifically to receptors known as? a. ligands b. enzymes c. allosteric enzymes d. hydrolases e. transcription factors 43. To which category do most receptor proteins belong? a. peripheral proteins b. internal proteins c. integral proteins d. glycoproteins e. nucleoproteins 44. Which of the following best describes the interaction between LDL and its receptor? a. Receptor that internalizes stimuli b. Receptor that functions as an ion channel c. Receptor that plays a catalytic role d. Receptor that generates internal chemical signals e. Receptor that is G-protein 45. What would be the effect of a glucokinase enzyme with a low Km? a. There will be no effect. b. Glucose will be removed from blood even at low glucose concentrations by the liver. c. The liver will not be able to synthesize adequate glycogen. d. Glucagon will not be secreted. e. Appetite will be reduced.

46. What does diagnostic enzymology focus on? a. enzymes that are widely distributed among many tissues b. intracellular enzymes that express their activity in the blood abnormally due to a disease process c. secreted enzymes such as clotting proteins in blood d. nuclear enzymes e. receptor enzymes 47. What is one possible trigger of apoptosis? a. overexpression of Bcl-2

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Chapter 01: The Cell: A Microcosm of Life b. inactivation of Casp-9 c. swelling of the cell d. release of mitochondrial cytochrome c e. inactivation of tumor necrosis factor 48. Malformed Apaf-1 molecules in a cell might a. cause rapid apoptosis of the cell b. inactivate cytochrome c c. lead to the development of a tumor d. terminate all protein synthesis in the cell

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e. have no effect on the cell 49. Which of the following is not a form of energy? a. oxygen b. heat c. kinetic d. Chemical e. mechanical 50. In muscle cells, creatine phosphate is used to replenish which substance? a. glucose b. pyruvic acid c. ATP d. calcium e. glycogen 51. What category of enzymes function in the electron transport chain in the mitochondria? a. hydrolases b. oxidoreductases c. transferases d. lyases e. ligases 52. What category of enzymes function as digestive enzymes? a. hydrolases b. oxidoreductases c. transferases d. lyases e. ligases 53. What category of enzymes catalyze reactions in which one functional group is moved from one substrate to another such as transaminases?

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Chapter 01: The Cell: A Microcosm of Life a. hydrolases b. oxidoreductases c. transferases d. lyases e. ligases 54. Which term describes a higher energy level or barrier at which the exothermic conversion to products takes place in a chemical reaction? a. Free energy b. Activation energy c. Cellular energy d. Transition state e. Standard reduction potential 55. Which term describes the potential energy released from chemical bonds upon oxidation? a. Free energy b. Activation energy c. Cellular energy d. Transition state e. Standard reduction potential 56. Which term describes the energy required to raise the reactants in a chemical reaction to their transition state? a. Free energy b. Activation energy c. Cellular energy d. Transition state e. Standard reduction potential 57. Which term describes the tendency of a compound to donate or receive electrons in a chemical reaction? a. Free energy b. Activation energy c. Cellular energy d. Transition state e. Standard reduction potential 58. What is a researcher in the field of nutritional genomics least likely to study? a. the interactions among genes and bioactive components in food that change gene expression without changing the DNA nucleotide sequence (nutritional epigenetics) b. inborn changes in DNA nucleotide sequences or gene variants (nutrigenetics) c. genetic alterations that can be compensated for by increasing or decreasing specific nutrients (nutrigenomics) d. the interaction between genetically engineered enzymes and their substrates

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Chapter 01: The Cell: A Microcosm of Life e. interaction between enzymes and pollutants in the atmosphere.

59. A common mutation in the 5,10-methylenetetrahydrofolate reductase enzyme (MTHFR) a. prevents the individual from activating the B vitamin folate

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b. has no effect on the activity of the enzyme c. increases the activity of the enzyme d. modifies the folate molecule directly e. increases the activity of vitamin B12 60. What lifestyle change would be most important to individuals with a common variant in the GST gene that impairs protection against toxins? a. increasing levels of daily exercise b. eating a low-fat diet c. increasing ingestion of cruciferous vegetables d. increasing intake of omega-3 fats e. reducing fiber in the diet 61. Which organelle do bioactive molecules need to travel to have effects on gene expression? a. Golgi apparatus b. plasma membrane c. nucleus d. mitochondrion e. lysosome 62. Which term describes energy-releasing reactions? a. free reactions b. activated reactions c. endothermic reactions d. transition reactions e. exothermic reactions 63. What can be triggered by defects in the apoptotic process? a. hypertension b. cardiovascular disease c. osteoporosis d. autoimmune disease e. viral disease 64. What is the term that refers to pathological cell death? a. cellulosis b. nephrosis c. apoptosis

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Chapter 01: The Cell: A Microcosm of Life d. necrosis e. oncosis 65. Which are highly specialized membrane proteins that modify the cell's response to its environment? a. transport proteins b. enzymes c. receptors d. peroxisomes e. filamentous proteins

Indicate whether the statement is true or false.

66. Receptors are the only type of protein found in the plasma membrane of cells. a. True b. False 67. The lipid bilayer determines the function of the plasma membrane, while the proteins are primarily responsible for the structure of the membrane. a. True b. False 68. Flagella and cilia are structural elements that are part of the cytoskeleton of the cell. a. True b. False 69. Glycoproteins with their carbohydrate moieties facing the outer cell surface provide asymmetry to the plasma membrane. a. True b. False 70. Different cells express different proteins because the DNA contained in their nucleus is made up of different genes. a. True b. False 71. Polysomes function to transcribe mRNA into proteins. a. True b. False 72. When discussing enzyme kinetics, Km refers to the substrate concentration at which the enzyme is saturated and functioning at maximal velocity. a. True b. False 73. If two enzymes (e.g., pyruvate dehydrogenase and pyruvate carboxylase) compete for the same substrate

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Chapter 01: The Cell: A Microcosm of Life (pyruvate), the one with the higher Km has less affinity and will be more active when pyruvate concentrations are high. a. True b. False 74. Most cellular reactions are irreversible because the same enzyme that catalyzes the conversion cannot catalyze the reverse reaction. a. True b. False 75. Regulation of enzyme activity by increasing the synthesis and thereby the concentration of the enzyme is an example of regulation by induction. a. True b. False 76. Most of the metabolic energy produced in cells is made in the mitochondria. a. True b. False 77. The nuclear envelope consists of a single membrane layer that separates the nucleus from the rest of the cell. a. True b. False 78. Transcription of DNA cannot be altered. a. True b. False 79. An increase in the concentration of a substrate will increase the rate of the enzyme-catalyzed reaction. a. True b. False 80. Oncosis results from cell injury and is associated with cellular swelling and swelling of the mitochondrial nucleus. a. True b. False

81. List the three mechanisms that can be used to regulate the function of a protein (e.g., an enzyme) and briefly (in one to two sentences) describe their key features.

82. Briefly describe the three levels in which gene expression is regulated.

83. Choose three of the following terms and in one sentence per term, provide a concise definition of that term: cytoskeleton, mitochondria, Golgi apparatus, transcription, translation, apoptosis, and cell signaling.

84. Briefly explain the structure of a phospholipid and its role in the plasma membrane?

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Chapter 01: The Cell: A Microcosm of Life 85. Describe the cytoskeleton (microtrabecular lattice) and its role as an intercommunication system of proteins and other macromolecules.

86. Define and describe diagnostic enzymology.

87. Describe the important implications of the high Km for glucokinase in terms of maintaining normal blood glucose after a meal and during fasting.

88. Describe the process of apoptosis in relation to the life span of the cell.

89. Briefly describe how energy is harnessed from macromolecules as compared to combustion.

90. Discuss the concept of coupled reactions in the transfer of energy.

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Chapter 01: The Cell: A Microcosm of Life Answer Key 1. a 2. a 3. b 4. b 5. b 6. b 7. c 8. c 9. b 10. d 11. b 12. d 13. b 14. a 15. d 16. a 17. b 18. c 19. b 20. d 21. c 22. a 23. a 24. a 25. d

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Chapter 01: The Cell: A Microcosm of Life 26. b 27. b 28. c 29. b 30. b 31. d 32. a 33. c 34. d 35. b 36. a 37. c 38. a 39. d 40. a 41. b 42. a 43. a 44. a 45. b 46. b 47. d 48. c 49. a 50. c 51. b

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Chapter 01: The Cell: A Microcosm of Life 52. a 53. c 54. d 55. a 56. b 57. e 58. d 59. a 60. c 61. c 62. e 63. d 64. d 65. c 66. False 67. False 68. True 69. True 70. False 71. False 72. False 73. True 74. False 75. True 76. True

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Chapter 01: The Cell: A Microcosm of Life 77. False 78. False 79. True 80. True 81. Mechanism 1: Covalent modification—no change in the abundance of a protein. Here, preexisting protein is made active or inactive by covalently modifying it (involves making or breaking covalent bonds). Examples include phosphorylation, carboxylation, glycosylation, or proenzyme activation by breaking a peptide bond.

Mechanism 2: Allosteric regulation—here we also are not changing the abundance of the protein (in this case an enzyme), but we are inhibiting or stimulating its activity—not by covalently modifying the protein, but by having something bind to it, resulting in a change in its conformation that affects its enzymatic activity. Typically, substrates, intermediates, or products along the pathway in which the enzyme participates bind to the enzyme. The book calls them modulators. A good example is ATP—ATP is the end point of a lot of pathways (glycolysis, TCA cycle) and as such, when it is abundant, that is a good sign that we have enough ATP/energy. Once the concentration of ATP reaches a certain level, it begins to bind some of the key enzymes in glycolysis and the TCA cycle and inhibits them. Why continue to make ATP if we have enough? Conversely, when ADP levels are higher than ATP (a sign we need energy), ADP binds to some of the same enzymes, with the result that ADP stimulates them to be more active (and thus make more energy). Then, when ATP levels begin to rise again... we are back to the beginning of the process when it all started.

Mechanism 3: Induction—inducing a gene to be expressed, thereby ultimately resulting in an increase in the abundance of a protein. This is accomplished by increasing transcription and/or translation of the corresponding gene/mRNA. [By definition, induction means to increase abundance; writing “increase and/or decrease” would be incorrect.]

[Note: For mechanism 1 or 3, the proteins we are talking about can be enzymes, transporters, and so forth. For 2, we are only talking about enzymes. Don’t let the term active confuse you—we use it mostly when we talk about enzymes, but an “active protein” means it is carrying out its function, be it catalytic or transport or anything else. Also note that mechanisms 1 and 2 are fast, whereas mechanism 3 is slower.]

82. Gene expression can be regulated at three levels that covers the process of gene expression.

Transcription-level: This involves the role of proteins or other molecules such as metals and vitamins that can play a role in regulating transcription by way of transcription factors. Transcription factors are the factors that can influence gene transcription. Effects of transcription factors can be seen in how they may enhance, inhibit or alter the frequency at which the gene is being expressed. In this manner, the environment is able to elicit a response from the cell through an effect on the transcription of the gene. Signal transduction mechanisms mediate this effect from the environment.

Processing-level: Processing level effects are directed toward the transcript or mRNA that is the result of gene transcription. Alternate ways of processing the mRNA can result in regulatory effects that can enhance, inhibit or alter the amount of mRNA available for the next step. One example of this level of activity is splicing effects.

Translation-level: These are control mechanisms that affect the translation of the protein. The various mechanisms at play here include localization of mRNA, interactions with other small RNAs or microRNAs. These types of interactions can influence the amount of protein being made as well as the degradation of the protein.

83. The cytoskeleton is a system of filaments and fibers that makes up the supportive structure of the cell. The cytoskeleton helps the cell with locomotion, localization of organelles. Maintenance of cell shape, transfer of molecules and intercellular communication.

Mitochondria are the organelles in virtually all cells that are responsible for the major portion of energy (ATP) production, utilizing metabolic processes including the TCA cycle, β-oxidation, parts of gluconeogenesis, and the electron transport chain.

The Golgi apparatus consists of a system of a system of stacked cisternae that work in close coordination with the

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Chapter 01: The Cell: A Microcosm of Life endoplasmic reticulum in protein synthesis. The Golgi apparatus is more involved in the modifications and processing changes made to newly synthesized proteins such as glycosylation that are necessary for proteins to be sorted and/or secreted.

Transcription is the nuclear process of copying one strand of DNA into a single-stranded mRNA and substituting the base uracil in place of thymine.

Translation is the process by which the genetic information carried by a molecule of mRNA becomes the sequence of amino acids in a protein.

Apoptosis is programmed cell death brought about by several different mechanisms designed to regulate the number of cells in a tissue.

Cell Signaling is the process whereby a cell communicates with its environment and responds to the signal by altering its activities such an gene expression.

84. The answer should include the following items: • • • •

A phospholipid has two fatty acids and a charged head group attached to a glycerol molecule.

The charged head group provides a polar side to the molecule that balances the hydrophobic nature of the fatty acids Amphipathic molecules have the advantage of aligning at the lipid-water interphase and to spontaneously assemble in a manner that keeps the hydrophobic portions of together and away from the aqueous environments.

Formation of a lipid bilayer is advantageous in that it acts a barrier and allows selective permeability depending on the proteins that are associated with the bilayer.

85. The answer should include the following items: •

• • •

The cytoskeleton (microtrabecular lattice) consists of microtubules (hollow structures), microfilaments (made of actin), and intermediate filaments (found in cells like neurons and in muscle and epithelial cells that are subjected to physical stress).

It provides a structure for organization of organelles and proteins such as enzymes to facilitate interactions with substrates such as glucose and oxygen, thus facilitating metabolic pathways in all cells.

The cytoskeleton provides a mechanism for cell locomotion in certain cells such as phagocytes.

The microtrabecular lattice is vital for cell activation and survival.

86. Diagnostic enzymology studies intracellular enzymes that, due to a problem within the cell, escape and act within the serum where they do not normally exist. The serum activity of these now displaced enzymes is measured, which allows for a determination of the site and extent of the cellular damage. An accurate determination of the site of the damage requires that the enzyme being measured must exhibit a high degree of organ or tissue specificity.

87. The answer should include the following items: • • • •

The high Km for glucokinase means that it requires a high concentration of glucose in the blood to be active.

Thus, it is not very active during fasting and so the glucose that comes into the liver during fasting can easily return to the blood for use by the brain and other cells.

After a meal, when a high concentration of glucose enters the liver, the glucose concentration is high enough that glucokinase phosphorylates glucose, trapping it inside the liver.

This action is important for lowering blood glucose and making sure that the excess glucose can be converted to

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Chapter 01: The Cell: A Microcosm of Life glycogen in liver.

88. The answer should include the following items: • • • • • •

Apoptosis refers to programmed cell death as distinguished from pathological cell death, which causes inflammation and possibly autoimmune reactions.

Apoptosis can be beneficial during development of an organism when cells are no longer needed as development progresses.

Apoptosis is thought to be detrimental when it leads to degenerative diseases such as Alzheimer’s. Thus, active research seeks to understand triggers and methods by which it might be controlled.

DNA damage, hypoxia, or other intracellular insults can cause release of mitochondrial factors, especially cytochrome c, which activates caspases and results in the beneficial apoptosis (death) of that damaged cell.

The mitochondrial membrane protein Bcl-2 can prevent apoptosis by blocking the release of cytochrome c. If Bcl-2 is upregulated, it can cause cell survival. Survival of a damaged cell can allow it to continue to grow and cause cancer.

Both the retinoic acid form of vitamin A and the active form of vitamin D are involved in these cell death and survival pathways. Research is needed to completely understand the beneficial control of cell death and survival.

89. The answer should include the following items: • • • •

The macronutrients contain energy in their chemical bonds.

Release of energy by combustion of these molecules would result in the oxidation of the molecules and conversion to carbon dioxide, water and heat energy as seen in the example of a candle burning.

The difference between simple combustion and metabolic oxidation lies in the conversion of part of the heat energy into chemical energy in the form of ATP. During oxidative phosphorylation, the energy is converted into the high energy phosphate bonds of ATP to be stored and released upon future hydrolysis. Some energy is still lost as heat and only about 40% is captured as ATP.

90. The answer should include the following items (note that students may provide other examples such as the coupling of phosphocreatine to creatine with the formation of ATP from ADP): • • • •

Coupled reactions allow metabolism to proceed because exothermic reactions that release energy are capable of driving endothermic reactions that require the energy released.

In metabolism, ATP is involved as the ideal intermediate because the breakdown of high-energy phosphate compounds such as creatine phosphate can drive the formation of the intermediate-energy bond that creates ATP from ADP. In turn, ATP can be hydrolyzed to form ADP and release the intermediate amount of energy in the bond in order to provide energy to, for example, add phosphate to glucose to form glucose-6-phosphate, the first step in the glycolytic breakdown of glucose.

The breakdown of ATP to ADP to release energy is said to be coupled to the input of energy required to add phosphate to glucose to create glucose-6-phosphate.

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Chapter 02:The Digestive System: Mechanism for Nourishing The Body

Indicate the answer choice that best completes the statement or answers the question.

1. Within the lamina propria, lying just below the epithelium, is the mucosa-associated lymphoid tissue (MALT), which . activates sphincters a. controls secretions from the mucosal glands b. contains white blood cells and protects against ingested microorganisms c. initiates peristalsis d. secretes mucus, hormones, and digestive juices into the lumen e. activates sphincters 2. Which structural component of the gastrointestinal tract lies within the muscularis externa and controls the contractions that cause motility? a. muscularis mucosae b. submucosal plexus c. myenteric plexus d. lumen e. plexus of Meissner 3. Which structure is considered an accessory organ for the digestive system? a. pancreas b. stomach c. small intestine d. spleen e. esophagus 4. Bile is most important for the digestion and absorption of a. carbohydrates b. proteins c. fats d. vitamins e. minerals

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5. What would be the most likely result of a decrease in the function of the salivary glands? a. a lack of triglyceride digestion b. bolus that is difficult to form c. bitter taste in the mouth d. diarrhea due to malabsorption e. pain in the mouth 6. What is the name of the enzyme in saliva that digests starch? a. lipase b. synthetase

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Chapter 02:The Digestive System: Mechanism for Nourishing The Body c. amylase d. lactase e. protease 7. Which substance is not found in saliva? a. mucus b. enzymes c. water d. proteases e. electrolytes 8. Which layer of the gastrointestinal tract is made up of connective tissue and acts as a protective outer covering? a. mucosa b. sub-mucosa c. muscularis externa d. serosa e. viscera 9. Which layer of the gastrointestinal tract contains the blood vessels, lymphatic vessels, nerves, and lymphoid tissue? a. mucosa b. sub-mucosa c. muscularis externa d. serosa e. viscera 10. What are Peyer’s patches? a. a group of cells in the esophagus that initiates peristalsis b. areas of diagonal muscles in the stomach c. skin rashes due to food allergies d. aggregates of lymphoid tissue with immune-protective function in some regions of the digestive tract e. areas of the gastric mucosa that produce acid 11. Which of the following contains endocrine cells in the pancreas? a. pancreatic duct b. islets of Langerhans c. sphincter of Oddi d. acinar cells e. duct cells 12. Where is pepsinogen produced? a. hepatocytes b. pancreatic exocrine cells

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Chapter 02:The Digestive System: Mechanism for Nourishing The Body c. salivary glands d. gastric chief cells e. small intestine 13. Where is collagenase produced? a. liver b. pancreas c. salivary glands d. stomach e. small intestine 14. Where is trypsinogen produced? a. liver b. pancreatic exocrine cells c. salivary glands d. stomach e. small intestine 15. Which cells produce amylase? a. hepatocytes b. pancreatic exocrine cells only c. salivary glands and pancreatic exocrine cells d. salivary glands only e. gastric chief cells 16. Where is cholic acid produced? a. liver b. pancreas c. mouth d. stomach e. small intestine 17. Which of the following describes the action of somatostatin? a. stimulates insulin secretion b. stimulates secretion of pancreatic juice c. stimulates pepsinogen secretion d. inhibits gallbladder contraction e. decreases gastric emptying 18. Which of the following describes the action of secretin? a. stimulates insulin secretion b. stimulates secretion of pancreatic juice

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Chapter 02:The Digestive System: Mechanism for Nourishing The Body c. stimulates pepsinogen secretion d. inhibits gallbladder contraction e. decreases gastric emptying 19. Which of the following describes the action of gastrin? a. stimulates insulin secretion b. stimulates secretion of pancreatic juice c. stimulates pepsinogen secretion d. inhibits gallbladder contraction e. decreases gastric emptying 20. Which of the following substances stimulates insulin secretion? a. somatostatin b. gastrin c. pancreatic polypeptide d. glucagon-like peptide e. secretin 21. Which of the following substances decreases gastric emptying? a. secretin b. glucagon-like peptide c. insulin d. pancreatic polypeptide e. somatostatin 22. Delayed gastric emptying is known as a. cholecystitis b. cholelithiasis c. gastritis d. gastroparesis e. emesis

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23. What product produced by neck cells in the oxyntic gland of the stomach protects the epithelium from mechanical and chemical damage? a. amylase b. pepsin c. gastrin d. mucus e. bile 24. Which cells, found both in the oxyntic glands and pyloric glands of the stomach, secrete hydrochloric acid and intrinsic factor?

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Chapter 02:The Digestive System: Mechanism for Nourishing The Body a. neck cells b. parietal cells c. chief cells d. enteroendocrine cells e. acinar cells 25. Which specialized cell of the gastric epithelium secretes a hormone? a. neck b. parietal c. chief d. G-cell e. mucosal 26. What do the chief cells secrete? a. gastrin b. mucus c. zymogens d. hydrochloric acid e. lipase 27. What do the parietal cells secrete? a. hydrochloric acid and intrinsic factor b. intrinsic factor and gastrin c. gastrin and zymogens d. zymogens and hydrochloric acid e. gastrin and lipase 28. When the pH of the stomach is increased to manage GERD, over time, the stomach may not be acidic enough. What is the most likely outcome of this strategy? a. lack of carbohydrate digestion b. decreased protein digestion c. destruction of bacteria in the stomach d. gastric ulcer e. decreased lipid digestion 29. Which glycoproteins bind water and are gel-forming? a. mucins b. proteoglycans c. prostaglandins d. zymogens e. cubilins

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Chapter 02:The Digestive System: Mechanism for Nourishing The Body 30. What are the products of the action of hydrochloric acid in the stomach? a. simple sugars b. amylose c. short-chain fatty acids d. denatured proteins e. lipids 31. Which of the following describes the action of Pepcid, a drug that is classified as an H2 receptor blocker? a. inhibits the secretion of hydrogen ions by the parietal cells b. inhibits the release of acetylcholine by the vagus nerve c. inhibits the binding of gastrin to the parietal cells d. inhibits the binding of histamine to the parietal cells e. stimulates gastrin secretion 32. Which medication inhibits hydrogen release into the gastric juice, which reduces GI mucosal irritation? a. Pepcid b. Nexium c. Tums d. Tagamet e. Milk of Magnesia 33. Which process allows gastric expansion with food intake with minimal impact on intragastric pressure? a. peristalsis b. receptive relaxation c. segmentation d. pendular movement e. gastroparesis 34. Where are the pyloric glands predominantly located? a. at the juncture of the esophagus and the stomach b. in the fundus and the body of the stomach c. in the antrum of the stomach d. in the cardiac portion of the stomach e. between the stomach and duodenum 35. Which phrase best describes the function of the crypts of Lieberkühn? a. mucus secretion b. glucose oxidation c. cellular differentiation d. amylase secretion e. gastrin secretion

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Chapter 02:The Digestive System: Mechanism for Nourishing The Body 36. In addition to the ductless endocrine cells that secrete insulin and glucagon, what other type of active tissue is found in the pancreas? a. liver-like cells that produce bile b. ductless absorptive tissue that controls bicarbonate c. acinar exocrine cells that produce digestive enzymes d. erythropoietic cells that produce red blood cells e. mucosal cells that absorb glucose 37. Pancreatic juice that enters the duodenum through the sphincter of Oddi contains all of the following EXCEPT a. digestive enzymes b. intrinsic factor c. anions such as bicarbonate and chloride d. cations such as sodium, potassium, and calcium e. water 38. In which part of the brain is the swallowing center located? a. the hypothalamus b. the medulla oblongata c. the thalamus d. the pons e. the substantia nigra 39. Which of the following is a disorder that affects the esophagus? a. atrophic gastritis b. GERD c. peptic ulcer disease d. Zollinger-Ellison syndrome e. Dumping syndrome 40. Which hormone’s major action is to neutralize intestinal contents by stimulating secretion of bicarbonate from the pancreas and by inhibiting gastric acid secretion and gastric emptying? a. gastrin b. secretin c. cholecystokinin d. GRP e. glucagon-like peptide 41. Dumping syndrome may be caused by . a. bacterial infections b. viral infections c. partial removal of the stomach to treat obesity d. gallstones

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Chapter 02:The Digestive System: Mechanism for Nourishing The Body e. peptic ulcer disease 42. What is the hormone primarily responsible for contraction of the gallbladder and release of bile into the duodenum? a. gastrin b. secretin c. cholecystokinin d. GRP e. Peptide YY 43. Bile salts are synthesized from cholesterol in the a. heart b. stomach c. liver d. gallbladder

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e. pancreas 44. Which of the following describes the structure of many of the digestive enzymes produced by the enterocytes? a. glycoproteins b. glycolipids c. proteoglycans d. mucopolysaccharides e. glycosaminoglycans 45. What percentage of bile is reabsorbed in the distal ileum? a. 10 percent b. 30 percent c. 65 percent d. 90 percent e. 100 percent 46. Which of the following might be the result of large gallstone blocking the cystic duct. a. a reduction in the production of bile by the liver b. an increase in bile production by the liver c. enhancement of fat digestion d. interference with fat digestion e. enhanced protein digestion 47. Which substance is enterohepatically circulated? a. pancreatic enzymes b. bile c. glucose d. CCK

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Chapter 02:The Digestive System: Mechanism for Nourishing The Body e. intrinsic factor 48. In general, in which portion of the gastrointestinal tract does absorption of most of the vitamins and minerals occur? a. esophagus b. stomach c. small intestine d. colon e. liver 49. A common cause of peptic ulcer disease (PUD) is the bacterium a. Escherichia coli b. Helicobacter pylori c. Staphylococcus aureus d. Enterobacter aerogenes

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e. Clostridium botulinum 50. Which structure helps to prevent the migration of bacteria from the large intestine back into the small intestine? a. the cecum b. the appendix c. the ileocecal valve d. the ileum e. the pyloric sphincter 51. Which hormone(s) is/are responsible for decreasing sodium absorption in the colon? a. glucocorticoids b. mineralocorticoids c. vasopressin d. glucagon e. insulin 52. Which of the following is not usually an effect of bacterial overgrowth in the small intestine? a. vitamin deficiencies b. mineral deficiencies c. malabsorption of nutrients d. breakdown of bile e. celiac disease 53. Which division of the nervous system decreases digestive tract motility and secretions? a. parasympathetic b. somatic c. adrenergic d. sympathetic

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Chapter 02:The Digestive System: Mechanism for Nourishing The Body e. peripheral 54. Which of the following does not have paracrine-type local effects in the regulation of digestion? a. somatostatin b. histamine c. glucagon-like peptide d. secretin e. insulin-like growth factor 55. A deficiency in secretion of cholecystokinin might lead to which problem? a. a reduction in gastric acid production b. difficulty digesting fats c. difficulty digesting proteins d. a buildup of intestinal gas e. difficulty in digesting carbohydrates 56. When diagnosing lactose intolerance, what is measured in the breath following oral consumption of 50 g lactose? a. methane b. hydrogen c. carbon dioxide d. sulfur e. nitrous oxide 57. Lactose intolerance is least common in . a. European Americans b. African Americans c. Native Americans d. Asian Americans e. Ethnic heritage does not influence lactose intolerance 58. Taking antihistamines might lead to a(n) . a. increase in stomach acid production b. increase in bile release c. decrease in stomach acid secretion d. reduction in pancreatic enzyme production e. reduction in bile synthesis 59. Which hormone increases appetite? a. ghrelin b. motilin c. secretin d. leptin

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Chapter 02:The Digestive System: Mechanism for Nourishing The Body e. corticotropin-releasing hormone 60. Among the regulatory peptide molecules, some have endocrine effects and others have paracrine effects. Which substance has an endocrine rather than a paracrine effect? a. secretin b. somatostatin c. histamine d. glucagon-like peptide e. insulin-like growth factor 61. What is the location of the enteroendocrine S-cell that releases secretin? a. proximal small intestine b. gastric mucosa c. esophagus d. colon e. gallbladder 62. A decrease in the function of the parotid glands is most likely to result in a. a lack of triglyceride digestion b. bolus that is difficult to form c. saliva that is too thin; that is, a high water to mucus ratio d. diarrhea due to malabsorption e. lactose intolerance

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63. Which of the following is a benefit due to colonic bacteria that is not directly linked to the generation of short-chain fatty acids? a. providing energy b. acidifying the luminal environment c. enhancing fecal bulk d. improving colonic blood flow e. increasing water and sodium absorption 64. RYGB surgery involves . a. creating a pouch after the proximal and distal portions of the stomach are separated b. placing a band on the stomach and creating a pouch c. removing 85 percent of the stomach surgically d. connecting the esophagus directly to the duodenum e. connecting the jejunum directly to the colon 65. Which nutritional deficiency occurs frequently following RYGB? a. vitamin D b. protein

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Chapter 02:The Digestive System: Mechanism for Nourishing The Body c. fat d. vitamin C e. thiamin

Indicate whether the statement is true or false.

66. Secretin stimulates HCl release. a. True b. False 67. CCK stimulates the release of pepsinogen from gastric chief cells. a. True b. False 68. Leptin secretion diminishes the desire to eat. a. True b. False 69. CCK stimulates the release of bile. a. True b. False 70. Colonic bacteria produce short-chain fatty acids when they ferment carbohydrates. a. True b. False 71. Plasma levels of ghrelin are high after a meal. a. True b. False 72. Colonic bacteria can enhance the strength of the host immune system. a. True b. False 73. The presence of acid in the stomach inhibits the secretion of gastrin. a. True b. False 74. Peptide YY stimulates gastric acid secretion. a. True b. False 75. Secretin stimulates gastric emptying. a. True b. False

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Chapter 02:The Digestive System: Mechanism for Nourishing The Body 76. Short-chain fatty acids secreted by intestinal bacteria improve colonic and splanchnic blood flow. a. True b. False 77. The predominant component of saliva is amylase. a. True b. False 78. The fundus of the stomach lies below the gastroesophageal sphincter. a. True b. False 79. Villi are designed to increase the absorptive surface area of the small intestine. a. True b. False 80. Pancreatitis occurs when zymogens become activated within the pancreas. a. True b. False

81. Discuss the role of drug therapies such as Tagamet, Zantac, and Pepcid in the treatment of peptic ulcers.

82. Briefly describe the beneficial effects of colonic bacteria that are independent from the effects of short-chain fatty acids.

83. What happens to reabsorbed bile acids after transported back to the liver? What would be the consequences if this reabsorption was inhibited?

84. Describe the mechanisms by which resin-type drugs and functional foods containing phytostanols lower high blood cholesterol levels.

85. Broad-spectrum antibiotics are capable of killing many different bacteria, including many of those that naturally live in the intestines. Develop a hypothesis regarding the effects of broad-spectrum antibiotics on the beneficial effects of gut flora.

86. What are probiotics and prebiotics? Give examples of each.

87. Discuss two benefits of the regulatory peptides in digestion and absorption.

88. Briefly describe the processes involved in the absorption of nutrients in the small intestine 89. Bariatric surgery involves removal or bypass of a large portion of the stomach. Speculate on how the production of ghrelin following bariatric surgery might affect appetite and explain your reasoning.

90. Discuss the functions and significance of the folds of Kerckring, the villi, and the microvilli.

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Chapter 02:The Digestive System: Mechanism for Nourishing The Body

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Chapter 02:The Digestive System: Mechanism for Nourishing The Body Answer Key 1. b 2. c 3. a 4. c 5. b 6. c 7. d 8. d 9. b 10. d 11. b 12. d 13. e 14. c 15. c 16. a 17. d 18. b 19. c 20. d 21. d 22. d 23. d 24. b 25. d

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Chapter 02:The Digestive System: Mechanism for Nourishing The Body 26. c 27. a 28. b 29. a 30. d 31. d 32. b 33. b 34. c 35. c 36. c 37. b 38. b 39. b 40. b 41. c 42. c 43. c 44. a 45. d 46. d 47. b 48. c 49. b 50. c 51. c

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Chapter 02:The Digestive System: Mechanism for Nourishing The Body 52. e 53. d 54. d 55. b 56. b 57. a 58. c 59. a 60. a 61. a 62. b 63. c 64. a 65. b 66. False 67. False 68. True 69. True 70. True 71. False 72. True 73. True 74. False 75. False 76. True

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Chapter 02:The Digestive System: Mechanism for Nourishing The Body 77. False 78. False 79. True 80. True 81. The answer should include the following items: • • • •

These drugs are H2 receptor blockers.

They block the ability of histamine to bind to its H2 receptor.

Therefore, acid release from the parietal cell is decreased.

Less acid reduces irritation at the site of the peptic ulcer.

82. The answer should include the following items: • • • •

Enhance the host immune defense system Displacement or exclusion of pathogenic bacteria by competitive inhibition Scavenging, sequestering or transformation of carcinogenic molecules Enhancing fecal bulk and dilution of fecal contents

83. The answer should include the following items: • •

Reabsorbed bile acids are broken down; reconjugated to amino acids and secreted into bile along with the newly synthesized bile acids.

When the reabsorption is inhibited or interrupted, all new bile acids have to be synthesized de novo from cholesterol, conjugated and secreted into the gallbladder.

84. The answer should include the following items: • • • •

Resins bind bile acids in the intestinal tract and interfere with recirculation of bile.

Phytosterols and phytostanols bind both bile acids and cholesterol and enhance fecal excretion, limiting recirculation to the liver.

As fewer recirculated bile acids return to the liver, hepatocytes must synthesize more new bile acids, using cholesterol to do so.

This increased use of cholesterol decreases blood cholesterol.

85. The answer should include the following items: • • •

Broad-spectrum antibiotics kill most “friendly” gut bacteria along with the pathogenic bacteria they are taken to kill.

Therefore, the logical hypothesis is that many of the beneficial effects of gut flora are abrogated by antibiotics.

Some of these effects that might be diminished are vitamin K and biotin production and generation of beneficial short-chain fatty acids for use by colon cells and absorption into the body.

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Chapter 02:The Digestive System: Mechanism for Nourishing The Body 86. The answer should include the following items: Probiotics are live microorganisms (that is, active cultures of specific strains of bacteria) that when administered in adequate amounts confer health benefits to its hosts. Prebiotics (discussed in more detail in Chapter 4) are substances that are not digested by human digestive enzymes but confer health benefits to the host by acting as substrates for the growth and/or activity of one or more species of healthful bacteria in the colon.

The most common probiotic bacteria are lactic acid bacteria, usually strains of Lactobacillus and Bifidobacterium genera.

To be considered a probiotic, the product must contain 100 million live active bacteria per gram. At present, probiotics are mostly consumed as yogurt with live cultures and as fermented or cultured milk and milk products (such as buttermilk and kefir). In the United States, yogurt is often fermented by Lactobacillus bulgaricus and Streptococcus thermophilus, and milk is usually fermented by L. acidophilus and L. casei. Other bacteria used to manufacture dairy products include Leuconostoc esntheroides, L. mesenteroides, and Lactococcus lactis. Other food sources of probiotics include miso, tempeh, and some soy beverages/products.

87. The answer should include two of the following items: •

• • • •

Regulatory peptides and hormones co-ordinate the process of digestion. This means that movement from one section to the next is synchronized. This is brought about by the influence of regulatory molecules on muscle layers and motility.

The secretion of substances is coordinated with the movement through the regions of the digestive tract. As food enters the stomach, gastric juice prepares the stomach for gastric events.

Regulatory peptides and hormones relay signals to the brain so that food intake can be initiated and terminated based on content in the digestive tract. Hunger and satiety are important signals in this respect.

This type of coordination also ensures that once food leaves one section of the digestive tract the muscle and secretory activities diminish and energy and wastage can be minimized.

Feedback and control are two mechanisms that result from the overall actions of the regulatory peptides and hormones.

88. The answer should include the following items: • • • •

Simple diffusion – processes based on concentration gradients Facilitated diffusion – processes based on concentration gradients and a protein transporter that facilitates the process Active transport – processes that utilize membrane transporters and absorb nutrients with the net expenditure of energy Pinocytosis – specialized process that involves the engulfing of large nutrient complexes in vesicles and subsequent movement into the cells.

89. The answer should include the following items: • •

Ghrelin is secreted primarily from endocrine cells of the stomach and acts in the brain to stimulate appetite.

If fewer cells are present or active after removal or bypass of the stomach, less ghrelin is likely to be produced to stimulate appetite and food intake should decrease.

90. The answer should include the following items:

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Chapter 02:The Digestive System: Mechanism for Nourishing The Body • • •

The folds of Kerckring, villi, and microvilli dramatically increase the surface area of the intestinal lumen exposed to products of digestion.

Cells lining the villi also produce digestive enzymes and regulatory peptides.

This is important because the large surface area maximizes absorption of nutrients and release of regulatory peptides produced in the gut.

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Chapter 03: Carbohydrates

Indicate the answer choice that best completes the statement or answers the question.

1. The majority of food energy consumed around the world comes from . a. fat b. protein c. carbohydrate d. vitamins e. all macronutrients contribute equally to the energy content of the diet.

2. Which of the following best describes the structure of a ketopentose? a. five carbons and a ketone group b. six carbons and an aldehyde group c. three carbons and an aldehyde group d. seven carbons and a ketone group e. six carbons and a ketone group 3. In which metabolic pathway does phosphofructokinase play a key regulatory role? a. glycogenesis b. glycolysis c. gluconeogenesis d. glycogenolysis e. pentose phosphate pathway 4. In which metabolic pathway does pyruvate carboxylase play a role? a. glycogenesis b. glycolysis c. gluconeogenesis d. glycogenolysis e. pentose phosphate pathway 5. In which metabolic pathway does glycogen phosphorylase play a key role? a. glycogenesis b. glycolysis c. gluconeogenesis d. glycogenolysis e. pentose phosphate pathway 6. In which metabolic pathway does glucose-6-phosphate dehydrogenase play a key role? a. glycogenesis b. glycolysis c. gluconeogenesis d. glycogenolysis

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Chapter 03: Carbohydrates e. pentose phosphate pathway 7. In which metabolic pathway do branching enzymes play a key role? a. glycogenesis b. glycolysis c. gluconeogenesis d. glycogenolysis e. pentose phosphate pathway 8. Which of the following is the major site of expression for the monosaccharide transporter GLUT1? a. erythrocytes, CNS, blood brain barrier b. liver, pancreatic β-cells, small intestine c. neurons, testis, placenta d. skeletal muscle, adipose tissue e. small intestine, kidney, skeletal muscle, adipose tissue 9. Which of the following is the major site of expression for the monosaccharide transporter GLUT2? a. erythrocytes, CNS, blood brain barrier b. liver, pancreatic β-cells, small intestine c. neurons, testis, placenta d. skeletal muscle, adipose tissue e. small intestine, kidney, skeletal muscle, adipose tissue 10. Which of the following is the major site of expression for the monosaccharide transporter GLUT3? a. erythrocytes, CNS, blood brain barrier b. liver, pancreatic β-cells, small intestine c. neurons, testis, placenta d. skeletal muscle, adipose tissue e. small intestine, kidney, skeletal muscle, adipose tissue 11. Which of the following is the major site of expression for the monosaccharide transporter GLUT4? a. erythrocytes, CNS, blood brain barrier b. liver, pancreatic β-cells, small intestine c. neurons, testis, placenta d. skeletal muscle, adipose tissue e. small intestine, kidney, skeletal muscle, adipose tissue 12. Which of the following is the major site of expression for the monosaccharide transporter GLUT4? a. erythrocytes, CNS, blood brain barrier b. liver, pancreatic β-cells, small intestine c. neurons, testis, placenta d. skeletal muscle, adipose tissue

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Chapter 03: Carbohydrates e. small intestine, kidney, skeletal muscle, adipose tissue 13. What type of bond holds two monosaccharides together? a. ionic b. hydrogen c. glycosidic d. peptide e. electrostatic 14. When compounds having identical molecular formulas and containing one or more chiral carbon atoms exist as mirror images of each other, they are said to be . a. symmetrical b. enantiomers c. rotated d. linear e. anomers 15. Name the model that depicts cyclized monosaccharides as lying in a horizontal plane with the hydroxyl groups pointing down or up from the plane. a. Haworth b. Fischer projection c. cyclized Fischer projection d. stereoisomer e. enantiomer 16. What term describes carbohydrates that are composed of two simple sugars? a. disaccharides b. polysaccharides c. monosaccharides d. trioses 17. What property of cyclized sugars can be used to identify the ends of polysaccharides? a. reducing property b. oxidizing property c. acidifying property d. glycosidic bonding property e. branching property 18. What is the most common digestible homopolysaccharide existing as both amylose and amylopectin? a. glycogen b. cellulose c. hemicellulose

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Chapter 03: Carbohydrates d. starch e. lignin 19. Which of the following homopolysaccharides made of glucose contributes the most energy to the ordinary diet? a. amylose b. amylopectin c. glycogen d. cellulose e. resistant starch 20. A homopolysaccharide that is important in human diets is digestion of this homopolysaccharide is . a. cellulose; glucose b. lactose; galactose

and the end product formed from the complete

c. glycogen; glucose d. starch; glucose e. verbacose: glucose 21. Which disaccharide is commonly found in mushrooms? a. glucose b. fructose c. trehalose d. galactose e. raffinose 22. What is the key enzyme in digestion of polysaccharides? a. starch amylopectin b. β-amylase c. α-dextranase d. α-amylase e. lactase 23. Although cellulose is a polymer of glucose linked through β-linkages, humans cannot digest it because a. they only produce α-amylase b. they produce insufficient quantities of β-amylase c. cellulose is resistant to the human form of β-amylase d. the β-linkages are too strong to be hydrolyzed e. human cellulase does not digest it adequately.

24. What is characteristic of chiral carbon atoms? a. They have four hydrogens attached to them b. They have two methyl groups and two hydrogens attached to them

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Chapter 03: Carbohydrates c. They have three hydrogen atoms and one methyl group attached to them d. They have four different atoms or groups attached to them e. They have an amino group and three hydrogens attached to them 25. Which cells secrete the enzyme isomaltase? a. enterocyte b. pancreatic acinar cell c. hepatocyte d. gastric mucosal e. salivary gland 26. Which enzyme hydrolyzes the α (1,6) bond in amylopectin. a. amylase b. sucrose c. lactase d. isomaltase e. disaccharidase 27. Where are disaccharidases synthesized? a. pancreas b. liver c. enterocyte d. chief cell e. parietal cell 28. Where is sucrose digestion initiated? a. pylorus b. fundus c. duodenum d. mouth e. colon 29. What is the name of the protein that is used to form the initial glycogen primer? a. phosphoporin b. glucokinase c. glycoporin d. glycogenin e. pyrophorin 30. Which of the following is disrupted in the genetic abnormality called glucose-galactose malabsorption? a. isomaltase b. SGLT1

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Chapter 03: Carbohydrates c. α-amylase d. lactase e. GLUT2 31. Choose the best description of the main method of glucose absorption. a. passive diffusion down a concentration gradient b. active transport with fructose c. facilitated transport d. active transport with sodium e. endocytosis 32. Which sugar is not present in the systemic circulation due to efficient removal and metabolism by the liver? a. glucose b. fructose c. galactose d. sucrose e. maltose 33. Which glucose transporter is sensitive to insulin? a. GLUT1 b. GLUT2 c. GLUT4 d. SGLT1 e. GLUT3 34. Which hormonal changes occur in response to a fall in blood glucose concentration? a. increased insulin, decreased glucagon b. decreased insulin, increased glucagon c. decreased insulin, decreased glucocorticoids d. increased insulin, increased glucagon e. decreased insulin, decreased glucagon 35. Glycemic load considers the in food. a. protein and carbohydrate content b. fat and carbohydrate content c. fat to carbohydrate ratio d. quantity and quality of carbohydrate e. carbohydrate to water ratio 36. People with type 1 diabetes have . a. slow translocation of GLUT4 transporters from the Golgi body b. lack of mRNA synthesis for GLUT4 transporters in adipocytes or myocytes

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Chapter 03: Carbohydrates c. increased glycogenesis in myocytes after a meal d. below-normal glucokinase activity because of low insulin levels e. mutated GLUT4 synthesis 37. Insulin is an anabolic hormone. Which process does insulin stimulate? a. lipolysis b. gluconeogenesis c. glycogenesis d. ketogenesis e. glycogenolysis 38. Which of the following catalyzes phosphorylation of glucose in the liver? a. glucokinase b. hexokinase c. insulin d. glucagon e. phosphorylase 39. Due to a lack of the enzyme glucose-6-phosphatase, which tissue capable of glycogenesis cannot contribute to blood glucose levels between meals? a. liver b. muscle c. brain d. kidney e. red blood cells 40. What mechanism is most often utilized by ATP, ADP and AMP to regulate metabolism? a. alternate translocation of enzymes b. hormonal activation c. allosteric modulation d. causing directional shifts in reactions e. causing changes in gene expression 41. Conversion of phosphorylase b to the active phosphorylase a is carried out by a. ADP b. AMP c. ATP d. cAMP e. GTP 42. In what part of the cell does glycolysis occur? a. mitochondrion

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Chapter 03: Carbohydrates b. cytosol c. nucleus d. endoplasmic reticulum e. lysosome 43. In which cellular site is most of the energy released when carbohydrates are oxidized to carbon dioxide and water? a. cytoplast b. endothelium c. Golgi body d. mitochondrion e. lysosome 44. Two hormones that stimulate glycogenolysis in the muscle and liver, respectively, are a. cortisol and epinephrine

.

b. epinephrine and glucagon c. insulin and epinephrine d. glucagon and insulin e. insulin and glucagon 45. Where are the enzymes that catalyze the citric acid cycle located? a. cytoplasmic matrix b. endoplasmic reticulum c. mitochondrial matrix d. lysosome e. nucleolus 46. Which substance is converted into glycogen in the process of glycogenesis? a. 2-phosphoglycerate b. glucose-1-phosphate c. fructose-1-phosphate d. phosphoglyceraldehyde e. glyceraldehyde-3-phosphate 47. In the complete oxidation of 1 mol of glucose, how many ATPs are formed? a. 4-6 b. 8-12 c. 18-24 d. 30-32 e. 14-16 48. The poison, sodium cyanide, inhibits the enzyme cytochrome c oxidase. Why is ingestion of this poison usually fatal? a. It blocks the production of ATP in the cells.

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Chapter 03: Carbohydrates b. It causes cells to rupture. c. It changes membrane permeability allowing important molecules to leave the cell. d. It causes changes in the acetyl-coenzyme A molecule. e. It destroys the lysosomes.

49. The conversion of pyruvate to oxaloacetate in gluconeogenesis allows which molecules to enter the gluconeogenic pathway? a. alcohols b. amino acids c. monosaccharides d. polysaccharides e. fatty acids 50. Alcohol in beverages is degraded mainly in the liver cytosol with the production of one NADH for each ethanol molecule. Predict what effect consumption of alcohol would have on the activity of the liver malate-aspartate shuttle. a. no change b. increased c. decreased d. reversed e. at first there is no change followed by a rapid decrease 51. Which process produces glucose-6-phosphate from noncarbohydrate sources? a. glycolysis b. glycogenolysis c. glycogenesis d. gluconeogenesis e. hexose monophosphate shunt 52. During the end reaction of the electron transport chain, molecular oxygen becomes a. oxidized to carbon dioxide b. reduced to water c. NADH + H+ d. FADH2 e. NADPH 53. Which of the following foods has the lowest glycemic index? a. Corn Flakes b. kidney beans c. mashed potatoes d. white bread e. spaghetti

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Chapter 03: Carbohydrates 54. Which of the following is a strong regulator of liver phosphorylase? a. AMP b. ATP c. glucagon d. insulin e. glucose-6-phosphate 55. The enzyme ATP synthase is believed to catalyze the formation of ATP, as described by the a. leakage b. hydrogen pump c. protein channel d. chemiosmotic e. hyperosmotic 56. The purpose of the hexose monophosphate shunt is to produce a. pentose phosphates and NADPH b. DNA and RNA c. fatty acids d. reducing substrates e. ATP

.

57. Which tissue has the least activity of the pentose phosphate pathway? a. liver b. adrenal cortex c. mammary gland d. skeletal muscle e. red blood cells 58. Gluconeogenesis is essentially the reversal of which pathway? a. glycogenesis b. glycolysis c. TCA cycle d. glycogenolysis e. alanine synthesis 59. All of the following are substrates for gluconeogenesis EXCEPT a. fatty acids b. lactate c. glycerol d. glucogenic amino acids e. ATP

.

theory.

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Chapter 03: Carbohydrates 60. Which of the following describes an anaplerotic process? a. synthesis of fatty acids from glucose b. synthesis of glycogen from glucose c. conversion of pyruvate to oxaloacetate d. conversion of pyruvate to glucose e. substrate level phosphorylation 61. If an individual with no blood sugar abnormalities when eating regularly presented with severe hypoglycemia after 30 hours of fasting, which enzyme would you suspect might be malfunctioning? a. phosphofructokinase b. pyruvate kinase c. fructose-1,6-bisphosphatase d. glucose-6-phosphatase e. glycogen synthase 62. In skeletal muscle, hypercortisolism may lead to a. enlargement of muscle fibers b. reduction in the size of muscle fibers c. increased contractile strength of muscle fibers d. increased healing capability e. increased performance potential

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63. From the data analyzed by the USDA for the years 1970-2010, which of the following statements is false about the American diet? a. Between 1970 and 2010, the availability of fructose from all food sources has increased. b. Between 1970 and 2010, the availability of glucose from all food sources has increased. c. carbohydrates are the most abundant macronutrient in the food supply. d. The second highest category that provides carbohydrates in the diet is sugar and sweeteners. e. Between 1970 and 2010, the availability of carbohydrate from grain products has increased 24%.

64. According to the USDA data for the year 2010, most of the carbohydrates in the American diet came from a. disaccharides b. monosaccharides c. grain products d. soft drinks e. fruits

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65. In the determination of glycemic index, for what period of time after ingestion of the specific food, is the elevation of blood glucose measured? a. 30 minutes b. 1 hour c. 2 hours

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Chapter 03: Carbohydrates d. 4 hours e. 8 hours

Indicate whether the statement is true or false.

66. GLUT4 is targeted to vesicles called GSVs for destruction. a. True b. False 67. Hormonal mechanisms represent one type of regulation in the synthesis and breakdown of glycogen. a. True b. False 68. Most enzyme-catalyzed reactions are irreversible. a. True b. False 69. Glucose is transported from the lumen into the enterocyte by active transport using SGLT1 protein, which also requires Na as a co-transporter. a. True b. False 70. SGLT1 functions in glucose active transport on the basolateral membrane of the enterocytes a. True b. False 71. The muscle is an important tissue in gluconeogenesis because it can use amino acids from protein breakdown and convert them to glucose, which it then secretes into the circulation for other tissues. a. True b. False 72. Glycogenolysis in muscle cells provides glucose that can be transported through the bloodstream. a. True b. False 73. Glucose phosphorylation is the first step in glycolysis and it is catalyzed by glucokinase in all cell types. a. True b. False 74. The Cori cycle would be active under anaerobic conditions, such as excessive muscle exertion. a. True b. False 75. Maintenance of normal blood glucose concentration is coordinated between tissues such as the small intestine, the liver, the kidneys, skeletal muscle, and adipose tissue and hormonal influences like glucagon and insulin.

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Chapter 03: Carbohydrates a. True b. False 76. Because they do not have mitochondria, red blood cells generate a lot of lactate from glycolysis, which they in turn convert into glucose to meet their energy needs. a. True b. False 77. All cells have mitochondria, which act as the main site for ATP production. a. True b. False 78. Active transport requires energy for the Na-K pump to transport Na out of the cell, thereby driving the transport of another substance (e.g., glucose) when the Na re-enters the cell down its concentration gradient. a. True b. False 79. Fructose transport into the enterocyte relies on the facilitative transporter GLUT5. a. True b. False 80. After hydrolysis of triacylglycerols stored in adipose tissue, free glycerol in the blood is converted in the liver to glucose via glycogenolysis. a. True b. False

81. Compare and contrast the glucose transporters and their role in glucose uptake.

82. A number of metabolic pathways have a problem in that certain components required for them to function are found in either the cytosol or the mitochondria, and some intermediates cannot cross the membrane. This requires that certain compounds be shuttled from one compartment to the other. Explain this shuttling process for either: (a) glycolysis/TCA cycle OR (b) gluconeogenesis. Your answer should include what needs to be shuttled, why it needs to be shuttled, and how this is accomplished.

83. Glycogenesis, glycogenolysis, gluconeogenesis, and glycolysis are tissue-specific—that is, either the pathway or certain aspects of the pathway are different for different tissues. Pick ONE metabolic process and describe what occurs, including what tissues are involved and any tissue-specific differences. Make sure to indicate any and all signals involved in this process.

84. Enzymes are regulated by induction, covalent regulation (a form of posttranslational modification), and allosteric modification. Pick out any THREE (3) enzymes from the enzymes involved in glycolysis, the TCA cycle, gluconeogenesis, glycogenesis, or glycogenolysis. Then, indicate: the reaction that the enzyme catalyzes; what tissue(s) this occurs in; how it is regulated (via one of the mechanisms listed above); and what signals are involved in its regulation. NOTE: Long answers are unnecessary—this can be done in a relatively short single sentence.

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Chapter 03: Carbohydrates 85. Discuss why lactose, ordinarily an easily digested carbohydrate, might present problems of flatulence and diarrhea in individuals with lactose intolerance.

86. What is the role of glycogen phosphorylase in metabolism? Discuss its action, location and regulation.

87. In anaerobic conditions the NADH produced in glycolysis is not reoxidized by oxygen in the mitochondria but is oxidized to NAD in the cytoplasm by an enzyme. What is the enzyme and what is the importance of this reaction for conditions of low oxygen level?

88. Discuss the chemiosmotic hypothesis of the mechanism by which the energy from electron transport is used to synthesize ATP. 89. Describe the process by which high levels of muscle lactate, produced by oxygen debt from exercise, are controlled/diminished by gluconeogenic action of the liver.

90. Does SGLT1 require energy for transport? Describe the active transport of glucose in the intestine?

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Chapter 03: Carbohydrates Answer Key 1. c 2. a 3. b 4. c 5. d 6. e 7. a 8. a 9. b 10. c 11. d 12. e 13. c 14. b 15. a 16. a 17. a 18. d 19. b 20. d 21. c 22. d 23. a 24. d 25. a

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Chapter 03: Carbohydrates 26. d 27. c 28. c 29. d 30. b 31. d 32. b 33. b 34. b 35. d 36. d 37. c 38. a 39. b 40. c 41. b 42. b 43. d 44. b 45. c 46. b 47. d 48. a 49. b 50. b 51. d

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Chapter 03: Carbohydrates 52. b 53. b 54. c 55. d 56. a 57. d 58. b 59. a 60. c 61. c 62. b 63. a 64. c 65. c 66. False 67. True 68. False 69. True 70. False 71. False 72. False 73. False 74. True 75. True 76. False

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Chapter 03: Carbohydrates 77. False 78. True 79. True 80. False 81. Answer should include the following: • • •

• •

All tissues can take up glucose through transporters (even when there isn’t any insulin).

Transporters have different properties such as specificity (e.g. GLUT5 transports fructose) Transporters vary in their characteristics such as Km (GLUT 2 has higher Km than GLUT 1). Differences in Km allow the transporters to determine the conditions under which maximal transport activity occurs such differences between fed and fasted states) Transporters vary in how they are regulated. GLUT4 is the only insulin responsive glucose transporter.

Transporters vary in their location. GLUT4 is found in muscle and adipose tissue. GLUT 2 is found in intestine, liver and pancreatic beta cells.

The different features of the transporters enable variation in control over the transporters giving the different tissues their own identity and place in coordination of the use of glucose for metabolism.

82. a) Glycolysis/TCA Cycle: The NADH generated by glycolysis needs to get in the mitochondrion for the electron transport chain (NADH from TCA cycle is already there). The malate-aspartate shuttle is used. Electrons (H+) from NADH are used to generate malate (from oxaloacetate), which crosses the membrane and gives them back to NAD to generate NADH (and oxaloacetate). Oxaloacetate is converted into aspartate, which crosses back to the cytosol and is metabolized to oxaloacetate to begin the process all over again. [Students may get this confused or mixed with the malate-oxaloacetate shuttle involved in gluconeogenesis.] (b) Gluconeogenesis: The problem is the need to get oxaloacetate out of the mitochondrion into the cytosol where the final conversion to glucose (via PEP) occurs. The amino acid alanine as well as glycerol and lactate enter gluconeogenesis as pyruvate, whereas other AAs feed into the TCA cycle at points dependent on the length of their carbon skeleton. In any case, we convert pyruvate to oxaloacetate (via pyruvate carboxylase) or any other TCA cycle keto acid to oxaloacetate. Oxaloacetate can’t cross the membrane, so it is converted into malate (or aspartate); malate (or aspartate) crosses the membrane, and it is converted back to oxaloacetate. Now, oxaloacetate can be converted into PEP by PEPCK and continue to be metabolized to glucose.

83. Glycogenesis occurs in muscle and the liver [the student should choose one tissue]. For either tissue, the signal is high blood glucose, which results in the release of insulin. For liver tissue, insulin induces glucokinase to increase glucose uptake by the liver. Insulin also stimulates (NOT induces) the dephosphorylation of glycogen synthase, resulting in its activation and the synthesis of glycogen. Note that insulin stimulates the enzyme (glycogen synthase phosphatase, which carries out the dephosphorylation of glycogen synthase, an example of covalent modification). Glycogen synthase and glycogen synthase phosphatase (or glycogen synthase kinase for that matter) are separate enzymes. Except for hexokinase (not induced by insulin) instead of glucokinase, the same mechanism occurs in muscle.

Glycogenolysis obviously also occurs in muscle and the liver. The signal is low blood glucose, resulting in the release of glucagon and epinephrine. For the liver, glucagon stimulates glycogen phosphatase b to a (same enzyme, a is just the phosphorylated form); it does this by stimulating the activity of a different enzyme, glycogen phosphatase kinase. In muscle, the signal is epinephrine, rather than glucagon. The result in both tissues is the breakdown of glycogen ultimately to glucose-6-phosphate. In liver tissue, glucagon also induces glucose-6-phosphatase, the enzyme that converts glucose-6-phosphate to glucose, which is then released into the blood. For muscle, there is no induction of

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Chapter 03: Carbohydrates glucose-6-phosphatase; thus, it simply proceeds through glycolysis/TCA to generate energy. So, liver glycogen results in glucose for the entire body; muscle glycogen only supplies energy for the muscle.

Gluconeogenesis occurs primarily in the liver and to some extent in the kidney. It involves the conversion of non-CHO precursors (AAs, lactate, glycerol) into glucose, which is then released by the liver into the bloodstream. This pathway is stimulated in response to low blood glucose and the subsequent action of glucagon, released by the pancreas due to low blood glucose. Glucagon induces many of the key enzymes (pyruvate carboxylase, PEPCK, fructose bisphosphatase, and glucose-6-phosphatase). Amino acids are converted into their corresponding keto acid and ultimately oxaloacetate, which must leave the mitochondria and be converted to PEP, etc.

Glycolysis is the oxidation of glucose to pyruvate, is cytosolic, and is anaerobic. Glycolysis occurs in all tissues/cells and is stimulated under fed conditions. High blood glucose leads to insulin secretion by the pancreas, which in turn induces glucokinase, PFK, and pyruvate kinase. Glucokinase is for liver tissue only—other tissues have hexokinase, which is not induced by insulin (but they still have PFK, etc.).

84. [There are many examples, so just a few are listed below, but they are probably the most common.]

Allosteric – all of the ones associated with ATP, ADP, NAD, and NADH are allosteric; ADP positively regulating PFK and ATP inhibiting it is an example. There are also isocitrate dehydrogenase, α-ketoglutarate dehydrogenase, and pyruvate dehydrogenase.

Covalent regulation – insulin stimulating the enzyme phosphatase, which dephosphorylates glycogen synthase (that’s the covalent regulation part), thereby promoting glycogen synthesis. The opposite reaction is glucagon (or epinephrine) stimulating the kinase that phosphorylates the enzyme phosphorylase b to generate phosphorylase a, the active form that breaks down glycogen to glucose-1-phosphate. Note – the hormones do not directly carry out covalent regulation; they stimulate (note the word stimulate, not induce) the enzyme that post-translationally modifies a second enzyme by phosphorylation or dephosphorylation to make it active or inactive.

Induction – many, many examples. Most common: insulin induces glucokinase (not hexokinase); PFK. Glucagon induces glucose-6-phosphatase; PEPCK. 85. Grading rubric – answer should include the following items: Lactose is digested by the disaccharidase lactase in the brush border of the small intestine. In lactose intolerance, the mucosal cells do not produce sufficient lactase; thus, undigested molecules of lactose travel to the large intestine where it draws water by osmosis, causing diarrhea. Gut bacteria ferment lactose with production of acids and gases (flatulence). This increases the abdominal discomfort due to malabsorption.

86. Grading rubric – answer should include the following items: • • • •

Glycogen phosphorylase is the main enzyme in the process of glycogenolysis which yield glucose.

Glycogen phosphorylase is found in muscle and liver and function as two different isozymes in these tissues.

In muscle, glycogen is broken down to yield glucose which can serve as energy to fuel activities in muscle. This results in glucose phosphate that can feed directly into the glycolytic cascade. Hence glycogen phosphorylase in muscle is regulated by energy (AMP).

In liver, glycogen is broken down to yield free glucose to maintain blood glucose concentrations. Hence, the enzyme is not regulated by energy but rather by glucose itself which determines if more glycogen needs to be broken down

87. Grading rubric – answer should include the following items: The enzyme is lactate dehydrogenase, which, under anaerobic conditions, catalyzes the transfer of two H+ from NADH +

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Chapter 03: Carbohydrates H to pyruvate to create lactate. This is important to regenerate NAD so that it can be used again in glycolysis. Glycolysis needs to be ongoing in conditions of low oxygen in order to generate ATP because oxidative production of ATP is compromised in conditions of low oxygen.

88. Grading rubric – answer should include the following items: Electron transport and ATP synthesis are said to be coupled because the energy used to pump protons from the mitochondrial matrix into the intermembrane space (called translocation of the protons) creates potential energy that can be harnessed by the enzyme complex ATP synthase to make ATP from ADP. As electrons pass through Complexes I, III, and IV of electron transport, sufficient energy is released to pump protons into the intermembrane space. This creates both a proton gradient and an electrical gradient across the inner mitochondrial membrane. When these gradients are sufficiently large, protons enter the channels provided by the ATP synthase molecule embedded in the mitochondrial membrane, the F0 portion. As the protons travel through the F1 portion of ATP synthase, which extends into the matrix and rotates as the protons pass through back into the matrix, the energy that causes the rotational movement drives the phosphorylation of ADP to create ATP. 89. Grading rubric – answer should include the following items: Lactate from muscles is released into the blood, from which it is removed by the liver. In the liver, lactate is converted to pyruvate, which then enters the gluconeogenic pathway to be converted to glucose and returned to the blood for use by other tissues. This process is called the Cori cycle.

90. Grading rubric – answer should include the following items: • • • • •

•

SGLT1 itself does not utilize energy for its function. It is a symporter that is located on the enterocyte luminal surface (apical side of the enterocyte).

SGLT1 simultaneously transports sodium and glucose (or galactose) into the enterocyte.

The sugar can only bind the transporter if sodium is already bound, thus exposing the sugar-binding site.

Sodium moves down a concentration gradient and is released inside the cell, which then releases glucose inside the cell.

In order to maintain the electrolyte concentrations in the compartments, sodium is pumped out against a concentration gradient into the extracellular fluid via the Na+/K+-ATPase pump on the basolateral membrane of the enterocyte. The sodium is exchanged for potassium pumped into the cell The net requirement of energy for the two processes is why this is an active transport mechanism. Use of ATP to make the exchange of sodium for potassium is a major energy demand of a body at rest (basal metabolic rate).

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Chapter 04: Fiber

Indicate the answer choice that best completes the statement or answers the question.

1. Dietary fiber is currently defined as . a. carbohydrates and lignin that are nondigestible by human enzymes and are intact and intrinsic in plants b. carbohydrates that are nondigestible by human enzymes; have been isolated, extracted, or manufactured and have been shown to have beneficial physiological effects in humans c. crude fiber d. the same as functional fiber e. carbohydrates from plant and animal sources that are nondigestible by human enzymes 2. Functional fiber is currently defined as . a. carbohydrates and lignin that are nondigestible by human enzymes and are intact and intrinsic in plants b. carbohydrates that are nondigestible by human enzymes; have been isolated, extracted, or manufactured and have been shown to have beneficial physiological effects in humans c. all dietary fiber d. the same as crude fiber e. carbohydrates from plant and animal sources that have been isolated and extracted; have been shown to have physiological benefits and that are nondigestible by human enzymes 3. Which of the following is considered a functional fiber? a. hemicellulose b. fructans c. psyllium d. lignin e. chitin 4. Dietary fibers are mainly provided by which of the following? a. proteins that have been heated with sugars b. plant cell walls c. chitin and chitosan d. plant gums e. plant polyols 5. Which of the following describes complex, hydrophobic hydrocarbon compounds that coat a plant’s external surfaces but do not contribute to the fiber content? a. bran b. endosperm c. waxes d. husk e. cutin 6. Which of the following describes a compound made up of polymeric esters of fatty acids that are secreted onto the plant surface but do not contribute to the fiber content?

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Chapter 04: Fiber a. bran b. endosperm c. waxes d. husk e. cutin 7. Which of the following is usually not found in the endosperm of the plant? a. starch b. cellulose c. hemicellulose d. resistant starch e. lignin 8. The germ layer of the kernel contains all of the following EXCEPT a. starch b. vitamins c. minerals d. essential fatty acids e. small amounts of fiber

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9. Which type of bond imparts a three-dimensional structure to cellulose? a. covalent b. ionic c. hydrogen d. glycosidic e. ester linkages 10. Which component of cereals contains the most fiber? a. germ layer b. endosperm c. husk d. bran e. all components contain similar amounts of fiber 11. Which type of food does not contain cellulose purified from wood? a. canned green beans b. cake mixes c. sandwich spreads d. fruit juice mixes e. frozen meat products 12. Which component of the cell wall contributes to the fiber content of foods?

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Chapter 04: Fiber a. waxes b. cutin c. bran layer d. suberin e. polyols 13. Which group of foods contains the greatest quantities of hemicellulose? a. legumes b. whole-grain cereals and bran c. fruits d. vegetables e. nuts 14. Which cereals contain more fiber than other grains? a. rye and barley b. wheat and corn c. rye and wheat d. oats and wheat e. rice and wheat 15. Which of the following statements is true about cellulose? a. Cellulose is a linear polymer of glucose units. b. Citrus fruits are a good source of cellulose. c. Naturally occurring cellulose is degraded by colonic bacteria. d. There is very little use for modified cellulose as a food additive. e. Cellulose is a charged molecule soluble in water.

16. Which of the following best describes lignin? a. The main noncarbohydrate component of fiber and a three-dimensional polymer of phenol. Found in carrots, berries, and wheat, and insoluble in water. b. A hydrocolloid composed of sugar and sugar derivatives commonly used as a food additive that is secreted from plant injuries or can also be found in oats, barley, and legumes. c. A long linear polymer that provides structure to the cell wall. Found in bran, legumes, root vegetables, and apples. d. Contains a number of sugars in its backbone and side chains. Some are water soluble and some are insoluble; found in bran and whole grains. e. A group of polysaccharides with galacturonic acid as a primary constituent. It is soluble and gel forming; plentiful in many fruits.

17. Which of the following best describes hemicelluloses? a. The main noncarbohydrate component of fiber and a three-dimensional polymer of phenol. Found in carrots, berries, and wheat, and insoluble in water. b. A hydrocolloid composed of sugar and sugar derivatives commonly used as a food additive that is secreted

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Chapter 04: Fiber from plant injuries or can also be found in oats, barley, and legumes. c. A long linear polymer that provides structure to the cell wall. Found in bran, legumes, root vegetables, and apples. d. Contains a number of sugars in its backbone and side chains. Some are water soluble and some are insoluble; found in bran and whole grains. e. A group of polysaccharides with galacturonic acid as a primary constituent. It is soluble and gel forming; plentiful in many fruits.

18. Which of the following best describes cellulose? a. The main noncarbohydrate component of fiber and a three-dimensional polymer of phenol. Found in carrots, berries, and wheat, and insoluble in water. b. A hydrocolloid composed of sugar and sugar derivatives commonly used as a food additive that is secreted from plant injuries or can also be found in oats, barley, and legumes. c. A long linear polymer that provides structure to the cell wall. Found in bran, legumes, root vegetables, and apples. d. Contains a number of sugars in its backbone and side chains. Some are water soluble and some are insoluble; found in bran and whole grains. e. A group of polysaccharides with galacturonic acid as a primary constituent. It is soluble and gel forming; plentiful in many fruits.

19. Which of the following best describes pectin? a. The main noncarbohydrate component of fiber and a three-dimensional polymer of phenol. Found in carrots, berries, and wheat, and insoluble in water. b. A hydrocolloid composed of sugar and sugar derivatives commonly used as a food additive that is secreted from plant injuries or can also be found in oats, barley, and legumes. c. A long linear polymer that provides structure to the cell wall. Found in bran, legumes, root vegetables, and apples. d. Contains a number of sugars in its backbone and side chains. Some are water soluble and some are insoluble; found in bran and whole grains. e. A group of polysaccharides with galacturonic acid as a primary constituent. It is soluble and gel forming; plentiful in many fruits.

20. Which of the following best describes gums? a. The main noncarbohydrate component of fiber and a three-dimensional polymer of phenol. Found in carrots, berries, and wheat, and insoluble in water. b. A hydrocolloid composed of sugar and sugar derivatives commonly used as a food additive that is secreted from plant injuries or can also be found in oats, barley, and legumes. c. A long linear polymer that provides structure to the cell wall. Found in bran, legumes, root vegetables, and apples. d. Contains a number of sugars in its backbone and side chains. Some are water soluble and some are insoluble; found in bran and whole grains e. A group of polysaccharides with galacturonic acid as a primary constituent. It is soluble and gel forming; plentiful in many fruits.

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Chapter 04: Fiber 21. Which of the following benefits provided by fiber is linked with cardiovascular disease? a. viscous, gel-forming fibers improve glycemic control b. non or less fermentable fibers increase fecal bulk c. fiber-rich foods and hormones such as ghrelin, peptide YY and cholecystokinin modulate appetite d. viscous, gel-forming fibers lower total and LDL cholesterol e. fiber reduces bile concentration, dilutes intestinal contents, and reduces colonic transit time 22. Which of the following benefits provided by fiber is linked with diabetes mellitus? a. viscous, gel-forming fibers improve glycemic control b. non- or less-fermentable fibers increase fecal bulk c. fiber-rich foods and hormones such as ghrelin, peptide YY and cholecystokinin modulate appetite d. viscous, gel-forming fibers lower total and LDL cholesterol e. fiber reduces bile concentration, dilutes intestinal contents, and reduces colonic transit time 23. Which of the following benefits provided by fiber is linked with satiety? a. viscous, gel-forming fibers improve glycemic control b. non- or less-fermentable fibers increase fecal bulk c. fiber-rich foods and hormones such as ghrelin, peptide YY and cholecystokinin modulate appetite d. viscous, gel-forming fibers lower total and LDL cholesterol e. fiber reduces bile concentration, dilutes intestinal contents, and reduces colonic transit time 24. Which of the following benefits provided by fiber is linked with constipation? a. viscous, gel-forming fibers improve glycemic control b. non- or less-fermentable fibers increase fecal bulk c. fiber-rich foods and hormones such as ghrelin, peptide YY and cholecystokinin modulate appetite d. viscous, gel-forming fibers lower total and LDL cholesterol e. fiber reduces bile concentration, dilutes intestinal contents, and reduces colonic transit time 25. Which of the following benefits provided by fiber is linked with colon cancer? a. viscous, gel-forming fibers improve glycemic control b. non- or less-fermentable fibers increase fecal bulk c. fiber-rich foods and hormones such as ghrelin, peptide YY and cholecystokinin modulate appetite d. viscous, gel-forming fibers lower total and LDL cholesterol e. fiber reduces bile concentration, dilutes intestinal contents, and reduces colonic transit time 26. Which of the following statements is not true about pectins? a. They are water soluble. b. They are gel-forming. c. They are stable at acidic pHs. d. They are stable at basic pHs. e. They are found in fruits.

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Chapter 04: Fiber 27. Which fiber is often added to foods as a thickening or texturing agent? a. lignin b. gums c. cellulose d. hemicellulose e. chitin 28. What is a water-soluble, gel-forming fiber that functions in the plant as intracellular cement and that is used commercially to make jellies and to provide fiber in enteral formulas? a. lignin b. gum c. pectin d. cellulose e. hemicellulose 29. What are the hydrocolloids that are secreted at a site of injury on a plant or surround the endosperm of some seeds and that are used as thickening agents? a. lignin b. cellulose c. pectins d. gums e. hemicellulose 30. What are plant polysaccharides found in flax and psyllium that are effective in reducing serum LDL cholesterol? a. beta-glucans b. fructans c. mucilages d. chitin e. resistant starches 31. Common food sources of fructans are . a. strawberries, apples, and citrus fruits b. whole grains c. chicory, onions, and Jerusalem artichokes d. legumes e. nuts 32. Which of the following fibers stimulates the growth of bifidobacteria and thus are considered prebiotics? a. lignins b. fructans c. β-glucans d. cellulose

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Chapter 04: Fiber e. hemicellulose 33. Which substance is used to replace fat in fillings, dairy products, and dressings? a. fructooligosaccharides b. mucilages c. inulin d. β-glucans e. cellulose 34. Which of the following is an example of an RS1 starch? a. unripe bananas b. whole grains and seeds c. avocados d. corn-based products e. berries 35. Which of the following is a predominant source of chitin? a. shells of crab, lobster, and shrimp b. bran c. vegetables d. fruits e. nuts 36. Which of the following are good sources of β-glucans in the diet? a. oat products and barley b. citrus fruits, strawberries, and apples c. chicory, asparagus, and onions d. bran, nuts, and legumes e. starchy vegetables 37. Which of the following are predominant sources of gums in the diet? a. nuts, peas, and root vegetables b. shells of crabs, shrimp, and lobster c. oatmeal, barley, and legumes d. citrus fruits, strawberries, and raspberries e. flaxseed and fruits with edible seeds 38. How is the glycemic response affected by foods rich in fiber or fiber supplements? a. It remains unchanged. b. It is improved. c. It is reduced. d. The effect is not known.

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Chapter 04: Fiber e. The response is biphasic.

39. Which of the following foods are most effective in lowering serum cholesterol? a. corn and wheat b. chitosan and chitin c. rice bran and wheat bran d. oat bran e. berries and citrus fruits 40. Where does fermentation of fiber mostly occur? a. ileum b. transverse colon c. descending colon d. rectum e. proximal colon 41. Which volatile short-chain fatty acid is believed to lower serum cholesterol by acting as an inhibitor of cholesterol biosynthesis? a. acetic b. butyric c. propionic d. palmitic e. lauric 42. Which of the following does fiber help to protect against because fibers absorb primary bile acids to promote their excretion? a. colon cancer b. diarrhea c. prostate cancer d. melanoma e. celiac disease 43. Which scenario is NOT a typical gastrointestinal response to ingestion of dietary fiber? a. increased glucose absorption b. delayed gastric emptying c. increased bile acid excretion d. increased fecal bulk e. feeling of satiety 44. By what mechanism do soluble fibers decrease the absorption of lipids? a. by increasing growth of bacteria that use the lipids b. by lowering blood cholesterol

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Chapter 04: Fiber c. by adsorbing/interacting with lipids d. by reducing mineral absorption e. by increasing bile acid absorption 45. Which of the following statements is true about galactans? a. Examples are raffinose, stachyose and verbacose. b. They are made up of 2-10 units of glucose and one unit of galactose. c. They are found in fruits. d. They can be broken down to some extent by human digestive enzymes. e. They are an insoluble fiber.

46. A manufacturer can claim that its product is an “excellent” source of fiber if the product contains at least what percentage of the recommendations for fiber? a. 5 b. 10 c. 15 d. 20 e. 25 47. Which of the following statements is true about resistant starches? a. They are composed of glucose units with glycosidic bonds similar to starch. b. They are categorized into ten sub-classes based on their characteristics. c. There are no health benefits to consuming this type of fiber. d. They can be broken down to some extent by human digestive enzymes. e. They cannot be fermented by colonic bacteria.

48. Which of the following types of foods contributes the most fiber in a usual serving? a. whole-grain breads b. legumes, beans c. meat, dairy d. leafy vegetables e. crabs and shellfish 49. What would a person who consumed a diet high in cellulose most likely suffer from? a. diarrhea b. constipation c. high blood pressure d. hyperglycemia e. nausea 50. Which of the following is a characteristic of viscous, gel-forming fibers? a. They can absorb several times their weight in water.

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Chapter 04: Fiber b. They can increase the reabsorption of bile in the ileum. c. They increase micelle formation. d. They increase interaction of food with digestive enzymes. e. They are found in green leafy vegetables.

51. What will be the effect of added gums on ice cream? a. It will be sweeter b. It will be thinner c. It will be creamier d. It will be lighter e. It will be sticky 52. Which of the following is not targeted for restriction in the low-FODMAP diet? a. maltose b. fructose c. polyols d. galactooligosaccharides e. lactose 53. What term best describes gums? a. fructooligosaccharides b. gacalactooligosaccharides c. hydrocolloids d. β-glucans e. corticoids 54. Which plant polysaccharides have a structure similar to gums? a. mucilages b. fructans c. β-glucans d. pectins e. celluloses 55. The health benefits of fiber are currently based on which two characteristics? a. viscosity and solubility b. viscosity and fermentability c. fermentability and solubility d. solubility and stability e. fermentability and absorbability 56. Which chemical characteristic describes most fibers? a. hydrophobic

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Chapter 04: Fiber b. allosteric c. hydromorphic d. hydrophilic e. non-polar 57. Which source of fiber would be the best to add to one’s diet in order to lower serum lipid concentrations? a. barley β-glucan and methylcellulose b. wheat dextrin c. pectin d. guar gum e. fructans 58. Fiber-induced shifts in bile acid production from cholic acid toward chenodeoxycholic acid will act to a. reduce blood glucose levels

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b. inhibit cholesterol synthesis c. lower blood pressure d. reduce the production of stomach acid e. stimulate overall synthesis of bile 59. Fiber fermentation in the colon may change glycogen catabolism due to the production of a. long-chain fatty acids

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b. chitosan c. oligosaccharides d. short-chain fatty acids e. lactic acid 60. Viscous gel-forming fibers may contribute to satiety by a. elevating serum glucose levels b. elevating glucagon levels c. slowing gastric emptying d. reducing hydrochloric acid in the stomach e. elevating levels of bile

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61. Diets low in fat and rich in high-fiber foods may reduce the risk of a. certain cancers b. heart disease c. gastric ulcers d. duodenal ulcers e. celiac disease

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62. good choice of a food to add to one’s diet in an effort to increase fiber intake while not consuming large portions is .

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Chapter 04: Fiber a. watermelon b. almonds c. grapes d. white rice e. oranges 63. Which are the two main compounds in the flavonol subclass of phytochemicals? a. quercetin and kaempferol b. apigenin and luteolin c. hesperetin and naringenin d. genistein and equol e. cyanidin and delphinidin 64. Current studies of the effects of flavonoids in humans most support protection against which disease? a. cancer b. diabetes c. osteoporosis d. cardiovascular e. osteoarthritis 65. Where are phenolic acids found? a. grapes, grape juice, red wine, and strawberries b. cruciferous vegetables c. coffee, blueberries, apples, pears, and cherries d. tomatoes, pumpkins, squash, and carrots e. fresh green herbs

Indicate whether the statement is true or false.

66. The ability of fiber to bind or hold water is called viscosity. a. True b. False 67. The germ is the most fiber-rich component of the kernel. a. True b. False 68. Ripe bananas are rich in resistant starch. a. True b. False 69. Hemicelluloses with acids in their side chains are fat soluble. a. True

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Chapter 04: Fiber b. False 70. β-glucans are effective in reducing serum cholesterol. a. True b. False 71. Galactooligosaccharides and fructooligosaccharides are broken down human digestive enzymes. a. True b. False 72. The repeating monosaccharide in stachyose and verbascose is fructose. a. True b. False 73. Pectins, gums, inulin, and resistant starches are structurally longer-chain, water-soluble fibers. a. True b. False 74. Fibers that are not fermented will help reverse constipation. a. True b. False 75. Low-fiber diets will lower blood glucose levels. a. True b. False 76. An individual whose diet is lacking in pectins and β-glucans will suffer from hypercholesterolemia. a. True b. False 77. An individual who consumes large amounts of strawberries and carrots might develop diarrhea. a. True b. False 78. Ingesting large amounts of fiber in excess of recommended levels may help to enhance absorption of iron and magnesium. a. True b. False 79. Foods may be considered a “good” source of fiber if they contain at least 5% of the recommendations for fiber. a. True b. False 80. No Tolerable Upper Intake Level for dietary fiber or functional fiber has been established. a. True

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Chapter 04: Fiber b. False

81. Discuss the three significant characteristics of dietary fiber that affect its physiological and metabolic roles.

82. Discuss how fibers protect against cardiovascular disease.

83. What are the components that make up fermentable dietary fiber and in what foods are each found?

84. Discuss the benefits of fibers and the risk of diabetes.

85. Discuss the benefits of fermentable fibers in terms of the production of short-chain fatty acids.

86. What are the components that make up non-fermentable dietary fiber and in what foods are each found?

87. What is the low FODMAP diet? Describe its characteristics and benefits 88. Discuss three health claims relating to fiber that have been approved by the U.S. Food and Drug Administration.

89. Dr. Smith has prescribed a high-fiber diet (35-40 g/day) with special emphasis on the water-insoluble fibers for Mr. Brown. How would this diet protect against colorectal cancer? Give examples of foods that contain water-insoluble 90. Make an argument defending the statement: To remain healthy, it is best to eat foods containing a variety of fiber types each day.

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Chapter 04: Fiber Answer Key 1. a 2. b 3. c 4. b 5. c 6. e 7. e 8. a 9. c 10. d 11. a 12. c 13. b 14. a 15. a 16. a 17. d 18. c 19. e 20. b 21. d 22. a 23. c 24. b 25. e

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Chapter 04: Fiber 26. d 27. c 28. c 29. d 30. a 31. c 32. b 33. c 34. b 35. a 36. a 37. c 38. b 39. d 40. e 41. c 42. a 43. a 44. c 45. a 46. d 47. a 48. b 49. a 50. a 51. a

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Chapter 04: Fiber 52. a 53. c 54. a 55. b 56. d 57. a 58. b 59. d 60. c 61. b 62. b 63. a 64. d 65. a 66. True 67. False 68. False 69. False 70. True 71. False 72. False 73. True 74. True 75. False 76. False

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Chapter 04: Fiber 77. True 78. False 79. False 80. True 81. Grading rubric – answer should include the following items: •

•

•

Solubility/insolubility in water. Pectins, gums, beta-glucans, fructans, psyllium, some resistant starches, and some hemicelluloses are soluble. Cellulose, lignin, some hemicelluloses and pectins, some resistant starches, chitosan, and chitin are insoluble. In general, soluble fibers delay gastric emptying and slow down transit time through the GI tract and slow glucose entry into the blood. Insoluble fibers increase fecal bulk and speed up transit time, which may expose the colon to fewer toxins.

Viscosity and gel formation. Soluble fibers have greater water-holding capacity, which traps nutrients and slows absorption, than insoluble fibers. Characteristics other than solubility that affect water-holding capacity are pH of the GI tract and particle size of the fiber (coarsely ground has more holding capacity). The more coarsely ground whole grains hold more water, slow gastric emptying, and reduce enzyme functions by separating enzymes from substrates. This gel-forming ability decreases nutrient diffusion rate and digestion of the nutrients.

Degradability/fermentability. Fiber always reaches the colon undigested because it cannot be digested by human enzymes. Gut bacteria can digest (i.e., ferment) some fibers. This helps gut bacteria grow and prebiotic fibers in particular support the growth of nonpathogenic, acid-producing bacteria that improve gut health. Some products of fermentation of fibers are the short-chain fatty acids that can improve health of colon cells and may inhibit synthesis of cholesterol to lower blood cholesterol levels. Short-chain fatty acids may also enhance gut immune function. Poorly fermentable fibers such as cellulose and lignin increase fecal bulk and speed transit time to promote more frequent defecation and quicker removal of toxins that might harm colon cells.

82. Grading rubric – answer should include the following items: • • • • •

Consumption of high-fiber foods, such as fruits and vegetables, has been associated with reduced systolic and diastolic blood pressure among those who suffer from hypertension. Hypertension is a risk factor for CVD. The viscosity and gel-forming property of fiber can interfere with interactions of nutrients such as lipids with enzymes and other components like bile which is necessary for adequate digestion. Micelle formation is inhibited and this reduces the rate of absorption of lipids.

Bile acids can adhere to the soluble fibers and be removed as waste. Bile acids are prevented from being recirculated to the liver. This forces the liver to make new bile acids from cholesterol, which could cause an increase in uptake of LDL cholesterol from the blood, and thereby could lower blood cholesterol.

Fermentation of fermentable soluble fibers by colonic bacteria produces short-chain fatty acids. Propionic acid has been shown to inhibit the rate-limiting enzyme in the synthesis of cholesterol (HMG-CoA reductase) by the liver. This could reduce circulating LDL levels.

For reasons unknown, the shift by fiber-inhibition of recirculation of bile acids that creates a different profile of bile acids by promoting increased chenodeoxycholic acid formation. This bile acid also inhibits HMG-CoA reductase and could lower synthesis of cholesterol.

83. Grading rubric – answer should include the following items (see Table 4.2):

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Chapter 04: Fiber Fermentable fibers must be able to be digested (fermented) by gut bacteria. Examples of fermentable fibers and foods that contain them include: • • • • • • •

fructans (chicory, asparagus, onions, tomatoes, bananas; also added to yogurts, cereals) pectins (fruits, legumes, nuts) gums (guar gum, gum Arabic; added as food additives that thicken) beta-glucans (oats, barley, mushrooms) polydextrose (created from glucose; used as a food additive for bulk; a functional fiber) resistant dextrins (extracted from cooked and cooled wheat to be added to foods; considered a functional fiber rather than a natural fiber) resistant starch 3 (cooked and cooled rice, potatoes, pasta)

84. Grading rubric – answer should include the following items: •

Some fibers are viscous and gel-forming. These types of fibers have effects on the digestive functions. o Gel-forming fibers interfere with movement through the digestive tract. Delayed gastric emptying gives a feeling of fullness and satiety. This reduced the food intake contributing lesser calories to the diet.

Overall, this can contribute to reduced weight gain. Weight gain and obesity is an independent risk factor for diabetes. o Reduced diffusion rates of nutrients would help minimize spikes in blood glucose thereby reduce glycemic effects of foods and insulin spikes that could result from it. o Fiber alters the gastrointestinal hormones and peptides involved in regulation of appetite such as ghrelin. This represents an added mechanism that helps in the satiety and satiation processes maintaining weight control and reduced risk of diabetes thereof. o Short chain fatty acids generated by fermentable fibers have shown to have beneficial effects on carbohydrate metabolism.

85. Grading rubric – answer should include the following items: • •

• • •

Fermentable fibers are used by gut bacteria to produce lactic acid and short-chain fatty acids that have several benefits.

All these acids decrease the pH to a more acidic environment, reducing the solubility of bile acids and allowing calcium to bind them and make them less toxic to colon cells. The acidity also decreases growth of pathogenic bacteria.

Short-chain fatty acids can be absorbed and used for energy.

Butyric acid is a preferred food for colonic mucosal cells (supplying 67% of their energy) and likely keeps them healthy, perhaps preventing colon cancer.

Propionic acid, when absorbed, can inhibit cholesterol synthesis, lowering blood cholesterol and risk for heart disease.

86. Grading rubric – answer should include the following items: Non-fermentable fibers cannot readily be digested (fermented) by gut bacteria. Examples and the foods that contain this type of fiber include: • •

Cellulose (cereal brans, legumes, nuts, root vegetables) Lignin (whole grains, especially wheat; mature root vegetables; seeds of berries; stalks of broccoli and

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Chapter 04: Fiber •

asparagus) Waxes (suberin and cutin, which coat the external surfaces of apples, potatoes, and similar fruits and vegetables)

87. Grading rubric – answer should include the following items: •

• •

The term FODMAP stands for “fermentable, oligo-, di-, monosaccharides and polyols.” These stand for some of the common triggers of gastrointestinal disorders such as irritable bowel syndrome. The low FODMAP diet is a diet with a list of foods to avoid to minimize the symptoms associated with these gastrointestinal disturbances such as bloating, flatulence, and abdominal cramping. In addition, fructose and lactose should also be restricted.

Variable symptom improvements have been reported from the FODMAP diet.

Foods to avoid include those with fructose, gums containing polyols, lactose from dairy, galactooligosaccharides from legumes and peas, and fructans.

88. Grading rubric – answer should include the following items: • • •

Diets low in fat and rich in high-fiber foods (or rich in fruits and vegetables) may reduce the risk of certain cancers.

Diets low in saturated fat (or low in fat) and rich in soluble fiber (or rich in whole oats and psyllium seed husk) may reduce the risk of heart disease.

Diets low in total fat, saturated fat, and cholesterol and rich in whole grains and other plant foods may help reduce the risk of heart disease.

89. Grading rubric – answer should include the following items: • •

•

Water-insoluble fiber will add fecal bulk and speed transit time of food through the GI tract.

Limited evidence suggests that fiber may reduce risk of cancer by several mechanisms including these: by adsorbing bile acids to promote their fecal excretion; by helping acidify the lumen of the colon, which keeps bile acids from being converted into more toxic secondary bile acids; by increasing fecal bulk to dilute concentrations of carcinogens from the diet; by shortening time undigested foods and toxins remain in the gut and so lessen exposure to toxins; by releasing calcium through fermentation to allow normal cells to grow as fast as cancer cells; and by producing butyric acid through fermentation to maintain health of colon cells.

Whole grains and vegetables have substantial amounts of insoluble cellulose and lignin.

90. Grading rubric – answer should include the following items: Different fibers have different helpful characteristics. Examples include: • • •

Cellulose, which increases fecal bulk and speeds transit time to remove toxins and carcinogens more quickly from the gut, likely reducing the risk of cancer.

Pectins and beta-glucans, which can keep bile acid and cholesterol from being absorbed into the blood, thereby reducing blood cholesterol and risk of heart disease.

Fermentable fibers such as fructans and gums can produce beneficial short-chain fatty acids to reduce risk of both cancer and heart disease.

To gain all these benefits, a variety of foods containing different fiber types need to be included in the diet daily.

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Chapter 05: Lipids

Indicate the answer choice that best completes the statement or answers the question.

1. Which of the following enzymes creates a double bond in a fatty acid? a. lipoprotein lipase b. hormone-sensitive lipase c. HMG-CoA reductase d. desaturase e. cyclooxygenase 2. Which of the following enzymes removes triacylglycerol from plasma? a. lipoprotein lipase b. hormone-sensitive lipase c. HMG-CoA reductase d. desaturase e. cyclooxygenase 3. Which of the following enzymes mobilizes stored triacylglycerols from adipocytes? a. lipoprotein lipase b. hormone-sensitive lipase c. HMG-CoA reductase d. desaturase e. cyclooxygenase 4. Which of the following is the rate-limiting enzyme in cholesterol synthesis? a. lipoprotein lipase b. hormone-sensitive lipase c. HMG-CoA reductase d. desaturase e. cyclooxygenase 5. Which of the following enzymes plays a role in the synthesis of prostaglandins? a. lipoprotein lipase b. hormone-sensitive lipase c. HMG-CoA reductase d. desaturase e. cyclooxygenase 6. Which of the following risks for cardiovascular disease is associated with trans fatty acids? a. atherogenic fatty plaque b. hypercholesterolemia c. raises LDL-C/lowers HDL-C d. shares structural homology with plasminogen; increases risk of CVD e. increases LDL’s affinity for macrophage receptors causing plaque

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Chapter 05: Lipids 7. Which of the following risks for cardiovascular disease is associated with lipoprotein (a)? a. atherogenic fatty plaque b. hypercholesterolemia c. raises LDL-C/lowers HDL-C d. shares structural homology with plasminogen; increases risk of CVD e. increases LDL’s affinity for macrophage receptors causing plaque 8. Which of the following risks for cardiovascular disease is associated with saturated and unsaturated fatty acids? a. atherogenic fatty plaque b. hypercholesterolemia c. raises LDL-C/lowers HDL-C d. shares structural homology with plasminogen; increases risk of CVD e. increases LDL’s affinity for macrophage receptors causing plaque 9. Which of the following risks for cardiovascular disease is associated with apolipoprotein E? a. atherogenic fatty plaque b. hypercholesterolemia c. raises LDL-C/lowers HDL-C d. shares structural homology with plasminogen; increases risk of CVD e. increases LDL’s affinity for macrophage receptors causing plaque 10. Which of the following risks for cardiovascular disease is associated with cholesterol levels in blood? a. atherogenic fatty plaque b. hypercholesterolemia c. raises LDL-C/lowers HDL-C d. shares structural homology with plasminogen; increases risk of CVD e. increases LDL’s affinity for macrophage receptors causing plaque 11. What is the range of carbon atoms in fatty acid chains found in foods and body tissues? a. 1 to 3 b. 2 to 6 c. 3 to 12 d. 4 to 24 e. 6 to 20 12. Which of the following is true of carbon-carbon double bond in the trans configuration in fatty acids? a. It results in a kinking of the fatty acid into a U-shape b. It extends the fatty acid into a linear shape c. It is required to create saturated fatty acids d. It is the hallmark of essential fatty acids e. It is most commonly found in foods we eat 13. Which fatty acid is considered essential and must be supplied by the diet? a. arachidonic acid

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Chapter 05: Lipids b. omega-9 fatty acid c. linoleic acid d. oleic acid e. stearic acid 14. Which unsaturated fatty acid is found in fish oil? a. alpha-linolenic b. eicosapentaenoic c. arachidonic d. oleic e. linoleic 15. How are lipids are different from other major nutrients? a. They contain carbon, hydrogen, and oxygen b. They are soluble in organic solvents c. They provide energy d. They are digestible e. They are metabolized in the body 16. How is most body fat stored? a. fatty acids b. triacylglycerols c. cholesterol d. phospholipids e. hormones 17. Ceramide is an example of what category of lipids? a. triacylglycerols b. sterols c. fatty acids d. sphingolipids e. phospholipids 18. What is the common lipid found in animal products that is characterized by a four-ring core structure? a. prostaglandins b. leukotrienes c. cholesterol d. glycolipids e. sphingolipids 19. In which cells would we find the highest concentration of sphingolipids? a. cardiovascular system b. digestive system c. reproductive system

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Chapter 05: Lipids d. central nervous system e. immune system 20. Which of the following statements is true about cholesterol? a. It is an important constituent of plasma membranes b. It is used to synthesize fatty acids c. Diet is our only source of cholesterol d. Most of the cholesterol in the body functions in blood with very little in the brain e. Digestive enzymes are made from cholesterol 21. Which of the following statements is true about phospholipids? a. They are amphipathic in nature b. They are found in high concentrations in muscle cells c. Diet is our only source of phospholipids d. Phospholipids do not participate in cell signaling reactions e. Phospholipids are built as a fatty acid to which three head groups are attached 22. An individual whose diet includes foods fried in vegetable oil, flaxseed oil supplements, and very little fish will have an abundance of which category of fatty acids? a. n-3 b. n-6 c. n-7 d. n-9 e. n-12 23. In processed foods, what are mono- and diacylglycerols used for? a. thickening agents b. emulsifying agents c. antioxidants d. food preservatives e. coloring agents 24. Which of the following statements is true about phosphatidylinositol? a. It can stabilize the cytoskeletal elements in the cell. b. It can form a monolayer around lipoproteins. c. It contains inositol groups that can be phosphorylated in response to stimuli and can then attract regulatory proteins to the membrane surface. d. It can act as an anchor protein for viruses to infect the cell. e. It can act as a communication channel to the outside of the cell.

25. Which combination of fatty acids together makes up more than 90% of the fatty acids in the average U.S. diet? a. Palmitic (16:0), Stearic (18:0), Oleic (18:1) b. Palmitic (16:0), Stearic (18:0), Oleic (18:1), Linoleic (18:2) c. Oleic (18:1), Linoleic (18:2), Alpha-Linolenic (18:3)

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Chapter 05: Lipids d. Myristic (14:0), Palmitic (16:0), Stearic (18:0), Oleic (18:1) e. Lauric (12:0), Myristic (14:0), Palmitic (16:0), Stearic (18:0), Oleic (18:1) 26. Which cells produce gastric lipase? a. neck cells b. parietal cells c. chief cells d. G cells e. S cells 27. What is the best description of the action of bile? a. Bile hydrolyzes ester bonds of the triacylglycerols. b. Bile anchors pancreatic lipase on to the surface of the dietary lipid. c. Bile emulsifies dietary lipid to increase its surface area. d. Bile digests the ester bond of the dietary cholesteryl ester. e. Bile activates pancreatic lipase.

28. How does undigested lipid in the stomach create satiety? a. It speeds the rate of emptying of the stomach b. It delays the rate of emptying of stomach contents c. It enhances gastric motility d. It suppresses GIP and secretin e. It increases the muscular action in the stomach 29. All of the following are required for digestion of fat EXCEPT: a. pancreatic lipase b. colipase c. bile d. leucine e. bicarbonate to elevate pH 30. How does orlistat reduce absorption of dietary fat? a. by replacing dietary fat with a synthetic, indigestible substitute b. by inhibiting the activity of pancreatic lipase c. by binding free fatty acids and causing their excretion d. by inhibiting HMG-CoA reductase e. by binding to bile and preventing emulsification 31. Where does pancreatic lipase begin to work? a. the duodenum b. the stomach c. the large intestine d. the last portion of the small intestine e. the colon

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Chapter 05: Lipids 32. What are some products of the reaction catalyzed by pancreatic lipase? a. 2-monoacylglycerols, free fatty acids b. free fatty acids, glycerol, cholesterol c. 2-monoacylglycerols, free fatty acids, phospholipids d. free fatty acids, glycerol, cholesteryl esters e. free fatty acids, cholesterol, phospholipids 33. In the small intestine, which enzyme hydrolytically activates a pancreatic zymogen so that lipid digestion can occur? a. pepsin b. trypsin c. colipase d. maltase e. enterokinase 34. Choose the list of molecules that would be found in a micelle. a. fat-soluble vitamins, glycerol, 2-monoacylglycerols, linolenic acid b. glycerol, butyric acid, cholesterol, 2-monoacylglycerols c. linolenic acid, 2-monoacylglycerols, cholesterol, fat-soluble vitamins d. fructose, glucose, glycerol, fat-soluble vitamins e. glycerol, 2-monoglycerols, butyric acid 35. Choose the correct sequential order for participants in lipid digestion. a. colipase, pancreatic lipase, bile, micelles b. bile, colipase, pancreatic lipase, micelles c. bile, enterokinase, colipase, micelles d. micelles, bile, pancreatic lipase, colipase e. co-lipase, micelles, bile, pancreatic lipase 36. Which of the following statements is true about micelles? a. They enter the enterocytes. b. They can stabilize circulating lipoproteins in the blood. c. They can enter the intramicrovillus spaces to interact with the brush border. d. They confer specificity for recognition by receptors on cells for the end products of digestion. e. They help pack the lipids into lipoproteins.

37. What describes the process by which bile salts are absorbed in the small intestine and returned to the liver to be recycled? a. micelle induction b. resecretion c. conjugation d. enterohepatic circulation e. extra-hepatic bile exchange

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Chapter 05: Lipids 38. What is the carrier for medium-chain fatty acids in portal circulation? a. triacylglycerides b. cholesterol c. chylomicrons d. albumin e. calcium 39. Which organ provides the major site for lipoprotein formation from exogenously derived lipids? a. pancreas b. adipose tissue c. intestine d. liver e. gallbladder 40. What are apolipoproteins unable to do? a. stimulate enzymatic reactions b. stabilize circulating lipoproteins in the blood c. decrease the density of the lipoprotein d. confer specificity for recognition by receptors on cells e. play a role in the structural stability of the lipoproteins 41. What does the liver synthesize to transport endogenous triacylglycerol? a. chylomicrons b. VLDLs c. LDLs d. HDLs e. IDLs 42. Which apolipoprotein is key to the delivery of triacylglycerol to tissues? a. apoC-2 b. apoA-1 c. apoE d. apoB-100 e. apoA-4 43. Which one of the following events will occur in the signaling pathway mediated by natriuretic peptides? a. increased intracellular cAMP activates protein kinase G b. ANP and BNP bind to type-B natriuretic peptide receptors c. activated receptors interact with guanylyl cyclase d. activated guanylyl cyclase converts intracellular AMP to cAMP e. hormone-sensitive lipase gets de-phosphorylated 44. What contributes the majority of saturated fatty acid in the average U.S. diet? a. dairy alone

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Chapter 05: Lipids b. red meats alone c. cooking oils alone d. red meats and dairy e. cooking oils, red meats, and dairy 45. Why are trans fatty acids considered to be dangerous to human health? a. They elevate serum glucose levels b. They raise LDL-C c. They lower HDL-C d. They raise LDL-C and lower HDL-C at the same time e. They raise LDL-C and lower HDL-C at the same time 46. Which of the following lipoproteins is normally NOT present in blood in the fasting state? a. VLDL b. chylomicrons c. LDL d. HDL e. IDL 47. Which of the following lipoproteins is the major carrier of cholesterol to tissues for use in construction of membranes or for synthesis of steroid hormones? a. VLDL b. HDL c. LDL d. chylomicrons e. IDL 48. The interaction between the receptors and which of the following components is key to the cell’s internalization of LDL? a. cholesterol acyltransferase b. HMG-CoA reductase c. apolipoprotein B-100 d. apolipoprotein C-100 e. apolipoprotein B-48 49. What is the result when abnormal LDL receptors fail to remove cholesterol from the bloodstream? a. suppression of acyl-CoA cholesteryl acyl transferase (ACAT) b. suppression of 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase c. hypertriglyceridemia d. familial hypercholesterolemia e. hyperglycemia 50. Which of the following carries out reverse cholesterol transport that removes cholesterol from peripheral cells and returns it to the liver?

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Chapter 05: Lipids a. LDL b. HDL c. VLDL d. lipoprotein lipase e. chylomicrons 51. Cooking oils contribute nearly all of which of the following components in the average U.S. diet? a. PUFA b. MUFA c. SFA d. cholesterol e. SFA and PUFA 52. Which drug therapy is associated with reduced cholesterol synthesis in the liver? a. insulin b. niacin c. gene therapy d. HMG-CoA reductase inhibitors e. glucagon inhibitors 53. What is the carrier molecule needed for mitochondrial membrane transport of long-chain fatty acids and their CoA derivatives? a. carnitine b. creatine c. creatinine d. cysteine e. glutathione 54. What is the end product of beta-oxidation? a. glycerol b. pyruvate c. acetyl-CoA d. triacylglycerol e. cholesterol 55. What are the end products when fatty acids are completely oxidized? a. fatty acid and glycerol b. carbon dioxide, energy, and water c. urea and acetate d. carbon, hydrogen, and phosphate e. urea and ATP 56. Ketones are produced from a. cholesterol

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Chapter 05: Lipids b. hormones c. amino groups d. acetyl-CoA e. glucose 57. When would ketogenesis be the HIGHEST? a. after a high-CHO meal b. after a high-protein meal c. after a high-fat meal d. during prolonged starvation e. after prolonged low-intensity exercise 58. What is the normal product of the fatty acid synthase system? a. triacylglycerol b. myristate c. palmitate d. butyrate e. oleate 59. What is the most important unsaturated fatty acid in membrane phospholipids that serves as a precursor for eicosanoid synthesis? a. arachidonic acid b. palmitoleic acid c. oleic acid d. linoleic acid e. stearic acid 60. Widespread use of cooking oils contributes to what percent of overall saturated fatty acid consumption in the average U.S. diet? a. 0 b. 5 c. 10 d. 20 e. 50 61. Identify a nonspecific response to injury involving phagocytic cells, neutrophils, and macrophages. a. inflammation b. atherosclerotic plaque formation c. blood clotting d. thermogenesis e. wound healing 62. How does hypertension increase the risk for CVD? a. It damages white blood cells.

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Chapter 05: Lipids b. It damages red blood cells. c. It leads to a disturbed repair process in arteries leading to aneurysms. d. It increases the risk of thromboses in veins. e. It increases white blood cell production.

63. The oxidation of ethanol increases the concentration of NADH. What effect does this have on tissues that metabolize ethanol? a. Increased lipolysis b. Increased triglyceride synthesis c. Increased bile acid synthesis d. Increased protein synthesis 64. Which integral membrane protein is uniquely found in the mitochondria of brown fat? a. fatty acid synthase b. catalase c. ATP Synthase d. UCP1 e. FATP 65. When foam cells, additional monocytes, mast cells, and T-cells build up in the media and intima of an artery, which structure is formed? a. atheroma b. hamartoma c. neuroma d. arterioma e. aneurhythmia

Indicate whether the statement is true or false.

66. Cooking oils, shortening, and red meats contribute the majority of monounsaturated fatty acids in the average U.S. diet. a. True b. False 67. Brown fat is metabolically the same as white fat except for the difference in color. a. True b. False 68. Ketogenesis occurs under conditions of excess glucose, such as in the fed state. a. True b. False 69. The gallbladder is the key organ responsible for maintaining cholesterol homeostasis in the body. a. True b. False

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Chapter 05: Lipids 70. Once a micelle, containing lipids and lipid-soluble compounds, enters the enterocyte, it is referred to as a chylomicron. a. True b. False 71. The key organ in clearing (i.e., breaking down) lipoproteins is the liver. a. True b. False 72. One of the primary functions of a phospholipid is possible because of its structure, which allows it to be both hydrophobic and hydrophilic. a. True b. False 73. Phytosterols are absorbed and transported in chylomicrons as efficiently as cholesterol itself. a. True b. False 74. Adipocytes’ primary function is to store fat as triacylglycerol; thus, they do not support the metabolic pathways of glycolysis and the TCA cycle for a supply of energy. a. True b. False 75. Unlike long-chain fatty acids, short-chain fatty acids from the diet leave the enterocyte via the portal vein and go directly to the liver. a. True b. False 76. Fatty acids are converted into glucose by gluconeogenesis and used for energy during starvation. a. True b. False 77. Bile is the GI enzyme that hydrolyzes dietary triacylglycerol into free fatty acids and glycerol. a. True b. False 78. The regulation of fatty acid synthesis and oxidation is closely linked to carbohydrate status. a. True b. False 79. Brown fat contains more mitochondria than white fat and is involved in thermogenesis. a. True b. False 80. Moderate alcohol intake is associated with an increased risk of coronary heart disease. a. True

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Chapter 05: Lipids b. False

81. Discuss the role of any three lipid/lipoprotein risk factors in relation to CVD. 82. Briefly explain the role of carbohydrates in the regulation of lipids.

83. Discuss three things that cannot be correct in the notation 18:2Δ8,9,19 when using the delta system of designating fatty acids.* *Source: Brody T, Nutritional Biochemistry, 2nd ed. Academic Press, San Diego, CA, 1999. page 643.

84. Describe fat metabolism in the adipose cell following a meal.

85. Describe the transport system that allows for fatty acid synthesis and the molecules involved in transferring acetylCoA into cytoplasm.

86. Briefly explain the role of the liver in cholesterol homeostasis.

87. Briefly describe the mechanism by which increased uncoupling protein opposes storage of energy as fat.

88. Which factors contribute to the color of brown fat and why does it generate heat?

89. Briefly explain the three systems that metabolize ethanol.

90. Describe three detrimental physiological effects of excess alcohol consumption and three beneficial effects of moderate alcohol consumption.

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Chapter 05: Lipids Answer Key 1. d 2. a 3. b 4. c 5. e 6. c 7. d 8. b 9. e 10. a 11. d 12. b 13. c 14. b 15. b 16. b 17. d 18. c 19. d 20. a 21. a 22. b 23. b 24. c 25. b

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Chapter 05: Lipids 26. c 27. c 28. b 29. d 30. b 31. a 32. a 33. b 34. c 35. b 36. c 37. d 38. d 39. c 40. c 41. b 42. a 43. c 44. e 45. d 46. b 47. c 48. c 49. d 50. b 51. a

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Chapter 05: Lipids 52. d 53. a 54. c 55. b 56. d 57. d 58. c 59. a 60. d 61. a 62. c 63. b 64. d 65. a 66. True 67. False 68. False 69. False 70. False 71. True 72. True 73. False 74. False 75. True 76. False

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Chapter 05: Lipids 77. False 78. True 79. True 80. False 81. Answers should include any three: • • • • •

Lipoprotein(a) – is a modified LDL particle with an apolipoprotein(a) glycoprotein which resembles plasminogen.

The presence of this modification varies due to genetic diversity and there are various isoforms that vary in pathogenicity and increase risk of heart disease.

Apolipoprotein E – is the isoform closely linked to heart disease and neurological dysfunction. It is based on genetic diversity. Its presence on LDL increases the affinity for macrophage receptors and this increase risk for heart disease.

Dietary cholesterol – is a controversial factor due to the tight regulation of overall body cholesterol homeostatic mechanisms. Other lipid components of the diet play a larger role in determining risk of heart disease than dietary cholesterol. There is little evidence to suggest that it is a strong risk factor.

Saturated and unsaturated fatty acids – have a strong influence on LDL cholesterol levels. The degree of unsaturation influences the strength of this risk. In general, saturated fats may have a hypercholesterolemic effect, but the evidence varies. MUFA and PUFA have better effects on lipid profile Trans fatty acids- represent a more unfavorable risk than any other type of fatty acids. They have the potential to raise LDL and lower HDL cholesterol.

82. The answer should include the following; • • •

Fed state – High levels of glucose will stimulate lipogenesis; High citrate levels will lead to high malonyl CoA and subsequently the synthesis of fatty acids. Beta oxidation will be inhibited by malonylCoA. Insulin also stimulates lipogenesis and inhibits lipolysis.

Fasted state – Low glucose levels suppress lipogenesis and stimulate lipolysis. Insulin levels drop and the inhibition on lipolysis is eased.

With starvation and low carbohydrate conditions, lipolysis continues under the depletion of oxaloacetate which increases ketogenesis. Now lipids are converted to an alternate fuel source.

83. Grading rubric – answer should include the following items: • • •

There are only two double bonds, but three locations for double bonds One location is at carbon 19, which does not exist in an 18-carbon chain Two double-bonds cannot be on two adjacent carbons (e.g., 8 and 9)

84. Grading rubric – answer should include the following items: • •

Following a meal, insulin increases the activity of lipoprotein lipase (LPL) in the blood vessels traversing the adipose tissue.

LPL hydrolyzes triglycerides in the chylomicrons delivered in the blood and fatty acids and monoacylglycerol are taken up into the adipocytes.

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Chapter 05: Lipids • •

Insulin also increases the entry of glucose into the adipocytes and stimulates glycolysis.

Acetyl-CoA from glycolysis not needed for energy production is used to create fatty acids through fatty acid synthase, also stimulated by insulin.

85. Grading rubric – answer should include the following items: • • • •

Because acetyl-CoA is formed in the mitochondria and fatty acids are synthesized in the cytoplasm, a carrier system is required to transfer acetyl-CoA to the cytoplasm.

Citrate from the combination of acetyl-CoA and oxaloacetate (first step of the TCA cycle) is able to pass through the mitochondrial membrane into the cytoplasm.

In the cytoplasm, citrate is cleaved by citrate lyase to reform acetyl-CoA and oxaloacetate in the cytoplasm.

The acetyl-CoA is then ready to be processed by acetyl-CoA carboxylase so that fatty acid synthesis can occur.

86. Grading rubric – answer should include the following items: • •

•

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The liver is central in cholesterol homeostasis as it regulates the synthesis of cholesterol to match the available cholesterol from the diet. Although many tissues have the ability to synthesize cholesterol, the liver does the greatest proportion of cholesterol synthesis.

HMG-CoA reductase catalyzes the reduction of 3-hydroxy-3-methylglutaryl-CoA to mevalonate, which is the rate-limiting step in the synthesis of cholesterol. This enzyme is inhibited by cholesterol to slow the in vivo production when dietary cholesterol is high or in vivo production has increased concentration of cholesterol sufficiently.

Chylomicron remnants and other lipoproteins such as LDLs and HDLs are cleared out by the liver. In this process, the components of the lipoproteins and disassembled and the cholesterol is added to the pools in the hepatocyte. The size of this pool determines the regulation of cholesterol synthesis through HMG-CoA reductase.

Bile acids are synthesized by the liver from cholesterol. When bile leaves the liver through the gall bladder, cholesterol and bile get into the lumen of the digestive tract and if there is any disruption in the reabsorption of bile salts they are excreted in the feces. This call for new bile salt synthesis using pool cholesterol from the liver cell.

In addition, liver cells store cholesterol as cholesterol esters for later use. Cholesterol from the pool can be packaged into VLDLs to distribute cholesterol to extra hepatic tissues.

87. Grading rubric – answer should include the following items: • •

• •

•

Energy is trapped as ATP because of the coupling of electron transport and oxidative phosphorylation.

The coupling occurs because hydrogen ions are pumped through the inner mitochondrial membrane into the intermembrane space during electron transport, and the tremendous gradient that builds up as a result has sufficient energy to create ATP when hydrogen ions flow back down the gradient into the mitochondrial matrix through the ATP synthase structures F0 and F1.

The energy released in electron transport that is not trapped by ATP is released as heat.

Uncoupling protein is an integral protein in the inner mitochondrial membrane that functions as a hydrogen ion channel, allowing hydrogen ions to seep back into the mitochondrial matrix without passing through ATP synthase structures. This “uncouples” electron transport from oxidative phosphorylation. Electron transport still creates metabolic water, but much of the energy released becomes heat and is not trapped as ATP. This uncoupling “wastes” food energy because less is trapped as ATP and more is released as heat. Such an

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Chapter 05: Lipids inefficient production of ATP from food energy would result in greater energy expenditure and less energy available for storage of energy as fat.

88. Grading rubric: answer should include the following items: • • • •

Brown fat is highly vascularized Brown fat contains in its adipocytes many mitochondria that contain cytochrome (a pigment) Other oxidative pigments associated with electron transport also have color Brown fat mitochondria contain uncoupling protein 1 (UCP1) that promotes thermogenesis at the expense of producing ATP

89. Grading rubric – answer should include the following items: •

•

•

The alcohol dehydrogenase system which metabolizes the majority of alcohol. In a two-step reaction, ethanol is first converted to acetaldehyde in the cytosol and in the next step yields acetate in the mitochondria through the action of acetaldehyde dehydrogenase. NADH and acetate can be used to get energy or acetate in excess is stored as fat.

When more ethanol than can be metabolized by the alcohol dehydrogenase pathway is present, the excess is metabolized through the cytochrome P-450 enzymes of the MEOS system. The enzymes and cytochromes of the MEOS system are inducible and increase over time with excess ingestion of alcohol. The more enzyme activity present in the system, the quicker that ethanol can be metabolized, and thus the more ethanol that can be ingested before intoxication begins.

The catalase system is present in peroxisomes and serves as a minor pathway to oxidize ethanol. It metabolizes ethanol in the presence of hydrogen peroxide.

90. Grading rubric – answer should include the following items: • • • • • •

Detrimental effects include induced metabolic tolerance, which allows heavy consumption of alcohol.

Alcohol dehydrogenase is the same enzyme that is called retinol dehydrogenase and that metabolizes vitamin A (retinol). As cytochrome P-450 is induced, a vitamin A deficiency can be developed unless extra vitamin A is eaten.

A high NADH:NAD ratio can result from metabolism of excess alcohol. This promotes use of acetyl-CoA from alcohol metabolism to synthesize fatty acids and can result in fatty liver.

Lactic academia is also a result of the high NADH:NAD ratio.

Impaired TCA cycle function and gluconeogenesis can also result from the NADH:NAD ratio because the reversible reaction catalyzed by isocitrate dehydrogenase favors the formation of glutamate in the presence of excess NADH. Beneficial effects of moderate alcohol consumption include the inverse relationship with heart disease in epidemiological studies; elevation of HDL, which may protect against atherosclerosis; and a beneficial relationship of moderate alcohol consumption with risk of dementia. In addition, polyphenols found in red wine may dampen reactive oxygen species and thus protect against excess inflammation that may exacerbate atherosclerosis.

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Chapter 06: Protein

Indicate the answer choice that best completes the statement or answers the question.

1. Which of the following describes chemical messengers secreted by endocrine tissue and transported to target organs where they regulate metabolic processes? a. enzymes b. hormones c. structural proteins d. immunoproteins e. transport proteins 2. Which of the following binds to nutrients and regulates their circulation and their flow into and out of cells? a. enzymes b. hormones c. structural proteins d. immunoproteins e. transport proteins 3. Which of the following binds to antigens and inactivates them or causes them to be destroyed? a. enzymes b. hormones c. structural proteins d. immunoproteins e. transport proteins 4. Which of the following are catalysts that change the rate of reactions occurring in the body? a. enzymes b. hormones c. structural proteins d. immunoproteins e. transport proteins 5. Which of the following are fibrous and contractile proteins found in bone, teeth, skin, muscles, blood vessels, and hair? a. enzymes b. hormones c. structural proteins d. immunoproteins e. transport proteins 6. Which of the following is/are the precursor(s) for the amino acid tyrosine? a. glutamate, ammonia b. glutamate c. phenylalanine d. methionine, serine e. glutamine, or glutamate, aspartate

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Chapter 06: Protein 7. Which of the following is/are the precursor(s) for the amino acid cysteine? a. glutamate, ammonia b. glutamate c. phenylalanine d. methionine, serine e. glutamine, or glutamate, aspartate 8. Which of the following is/are the precursor(s) for the amino acid proline? a. glutamate, ammonia b. glutamate c. phenylalanine d. methionine, serine e. glutamine, or glutamate, aspartate 9. Which of the following is/are the precursor(s) for the amino acid arginine? a. glutamate, ammonia b. glutamate c. phenylalanine d. methionine, serine e. glutamine, or glutamate, aspartate 10. Which of the following is/are the precursor(s) for the amino acid glutamine? a. glutamate, ammonia b. glutamate c. phenylalanine d. methionine, serine e. glutamine, or glutamate, aspartate 11. Why do zwitterionic amino acids have no net electrical charge? a. Because their side chains are not charged. b. Because they migrate to a neutral place in an electrical field. c. Because they are essential/indispensable. d. Because they have an amino group in their side chain. e. Because they are hydrophobic.

12. What happens when the diet is lacking in the amino acids lysine and threonine? a. Proteins will be made without lysine or threonine. b. The body will synthesize them. c. Protein synthesis will be limited. d. Another amino acid will be substituted so that synthesis is uninterrupted. e. Available amino acids will be modified for use as lysine or threonine.

13. What is a function of hydrochloric acid in gastric juice during protein digestion?

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Chapter 06: Protein a. To neutralize the acidity of the stomach b. To inactivate pepsinogen by suppressing pepsin formation c. To denature the quaternary, tertiary, and secondary structures of protein d. To cleave peptide bonds e. To make the carboxy terminal amino acids available for protease digestion 14. Choose the correct order of enzyme activities in protein digestion. a. tripeptidases, carboxypeptidases, pepsin, free amino acids b. trypsin, pepsin, collagenase, dipeptidases c. pepsin, trypsin, chymotrypsin, carboxypeptidase d. trypsinogen, enteropeptidase, dipeptidase, chymotrypsin e. pepsin, chymotrypsin, dipeptidase, trypsin 15. A mutation in which gene results in phenylketonuria (PKU)? a. phenylalanine dehydrogenase b. tyrosine dehydrogenase c. alkaline phosphatase d. phenylalanine hydroxylase e. tyrosine hydroxylase 16. Which of the following activation processes is not true? a. HCl activates pepsinogen b. Chymotrypsin activates trypsinogen c. Trypsin activates procarboxypeptidases d. Enteropeptidase activates trypsinogen e. Trypsin activates chymotrypsinogen 17. In general, where does most amino acid absorption occur? a. stomach b. duodenum and jejunum c. ileum d. colon e. mouth 18. Which of the following statements is true about the absorption of protein? a. One single type of transporter helps transport all amino acids across the enterocyte membrane. b. Basic or acidic amino acids are absorbed at higher rates than neutral amino acids. c. It is useful to consume large concentrations of single amino acids for better absorption. d. Majority of amino acids are absorbed as peptides. e. All amino acids are absorbed at the same rate.

19. Following ingestion of a protein-containing meal, which organ is the primary site of uptake of amino acids? a. liver b. muscle

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Chapter 06: Protein c. brain d. kidney e. red blood cells 20. Which organ derives 50% of its energy from oxidation of amino acids? a. kidney b. muscles c. liver d. intestine e. brain 21. Which three amino acids cannot undergo transamination to an appreciable extent, making provision of their alpha-keto acids ineffective in lowering blood nitrogen concentrations in kidney disease patients? a. leucine, isoleucine, valine b. lysine, threonine, histidine c. valine, tryptophan, phenylalanine d. methionine, cysteine, phenylalanine e. glutamate, methionine, lysine 22. Three important enzymes function in the removal of ammonia from cells in the body. One is carbamoyl phosphate synthetase I. What are the other two? a. branched-chain alpha-keto acid dehydrogenase and phenylalanine hydroxylase b. alanine aminotransferase and aspartate aminotransferase c. glutaminase and threonine dehydratase d. glutamate dehydrogenase and glutamine synthetase e. alkaline phosphatase and lactate dehydrogenase 23. Urea synthesis occurs partly in the mitochondria and partly in the cytosol of the a. glomeruli b. tubules c. enterocytes d. hepatocytes e. neurons

.

24. Using two high-energy bonds, arginosuccinate synthetase joins aspartate and citrulline to produce argininosuccinate in the cytosol. This is the rate-limiting step in synthesis. a. pyrimidine b. purine c. urea d. creatine e. ATP 25. When the amino group has been removed from an amino acid, the carbon skeleton or α-keto acid may be used in many different ways. Which of the following is NOT a possible fate for the carbon skeleton? a. conversion to glucose

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Chapter 06: Protein b. oxidation for energy c. synthesis of fat d. synthesis of creatine e. synthesis of ketones 26. Which of the following amino acids is ketogenic? a. glycine b. alanine c. leucine d. aspartate e. glutamine 27. What is the genetic disorder associated with a defective homogentisate dioxygenase enzyme that affects tyrosine degradation? a. maple syrup urine disease b. alkaptonuria c. homocystinuria d. phenylketonuria e. Hartnup’s disease 28. Which of the following is a non-protein compound that can be synthesized in the body and functions as a component of phospholipids and sphingomyelin? a. pyrimidine b. carnitine c. choline d. glutathione e. creatine 29. Serotonin is made from which amino acid? a. tyrosine b. niacin c. threonine d. tryptophan e. phenylalanine 30. Which of the following is a non-protein compound that is synthesized in the kidney and liver from arginine and glycine and is found primarily in muscle and acts as a storehouse for high energy phosphate? a. pyrimidine b. carnitine c. choline d. glutathione e. creatine 31. The branched-chain amino acids found in the systemic circulation include

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Chapter 06: Protein a. glycine, alanine, threonine b. phenylalanine, tyrosine, tryptophan c. valine, leucine, isoleucine d. arginine, lysine, histidine e. lysine, leucine, tyrosine 32. Which amino acids are mostly metabolized in skeletal muscles? a. Amino acids with side chains containing aromatic rings b. Amino acids with side chains that are branched c. Amino acids with side chains containing basic groups d. Amino acids with side chains containing sulfur atoms e. Amino acids with side chains containing acidic groups 33. Which level of organization determines the final form of a protein molecule consisting of several polypeptide chains? a. primary b. secondary c. tertiary d. quaternary e. ternary 34. Which of the following is a nitrogen-containing, nonprotein compound that is synthesized from glycine, cystine, and glutamate and functions as a major antioxidant in cells and plasma? a. glutathione b. carnitine c. pepsin d. actin e. choline 35. All of the following are effects of insulin on protein synthesis except: a. insulin stimulates oxidation of amino acids. b. insulin stimulates movement of amino acid transporters to the cell membrane. c. insulin promotes uptake of amino acids d. insulin inhibits enzymes responsible for degradation of amino acids. e. insulin works with leucine in stimulating protein synthesis.

36. Purine degradation results in the formation of xanthine and creation of a. polyamines b. gout c. citric acid d. uric acid e. urea

by xanthine oxidase.

37. Which amino acid is so important for several metabolic pathways in enterocytes that it is often added to nutritional mixtures used for hospitalized patients?

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Chapter 06: Protein a. tryptophan b. glutamine c. glycine d. asparagine e. glutamate 38. Which genetic defect is the result of diminishing branched-chain alpha-keto acid dehydrogenase (BCKAD) complex activity? a. phenylketonuria b. homocystinuria c. cystathioninuria d. maple syrup urine disease e. alkaptonuria 39. Which amino acid, when oxidized in muscle, spares the essential gluconeogenic precursors pyruvate and lactate? a. cysteine b. alanine c. leucine d. glutamine e. glutamate 40. What percentage of resting energy expenditure is attributed to protein synthesis and degradation? a. 9% b. 10-25% c. 30-40% d. 45-55% e. over 65% 41. What two major systems are used for protein degradation in most cells? a. mitochondrial and cytosolic pathways b. u-calpain and m-calpain pathways c. GTP-requiring and GTP-independent pathways d. lysosomal and ubiquitin-proteasomal pathways e. apoptosis and oncosis pathways 42. Legumes are limited in sulfur-containing amino acids, methionine, and cysteine. What food group is considered complementary because it supplies these amino acids? a. fruits b. nuts c. grains d. starchy vegetables e. dairy 43. What is one of the more common ways to evaluate protein quality in a food that does not involve nitrogen balance

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Chapter 06: Protein studies? a. chemical score b. net dietary protein calories percentage c. biological value d. net protein utilization e. net protein application 44. When evaluating protein quality, which of the following measures represents the gain in body weight on a test protein divided by the grams of protein consumed? a. chemical score b. BV (biological value) c. PER (protein efficiency ratio) d. NPU (net protein utilization) e. PDCAAS 45. What is the current Tolerable Upper Intake Level established for protein and amino acids? a. ingestion of a diet supplying > 30% energy from protein b. two times the RDA c. 42 mg/kg/day d. no Tolerable Upper Intake Level has been established e. five times the RDA 46. Which of the following describes a measure of how much nitrogen is retained in the body for maintenance and growth rather than absorbed? a. protein efficiency ratio b. biological value c. net protein utilization d. Tolerable Upper Intake Level e. PDCAAS 47. Where does the DIAAS assess the digestibility of the amino acids? a. ileum versus the colon b. ileum versus the jejunum c. ileum versus the duodenum d. duodenum versus the colon e. stomach versus the colon 48. The amino acid reference pattern established for all people (except infants) is the amino acid requirements of a. high school students aged 15-18 b. middle school children aged 11-13 c. preschool children aged 1-3 d. adolescents aged 13-16 e. children aged 6-10

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Chapter 06: Protein 49. The measurement of food nitrogen consumed rather than retention of food nitrogen absorbed is called the a. protein efficiency ratio b. biological value c. chemical score d. net protein utilization e. PDCAAS

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50. Which protein does the FDA specify as a standard for comparison of protein quality? a. casein b. albumin c. globulin d. gluten e. soy 51. What is assessment of nitrogen intake based on? a. amino acid intake b. protein intake c. carbohydrate intake d. lipid intake e. overall energy 52. What is the Estimated Average Requirement for protein for adults (men and women aged 19 years and older)? a. 5 g of protein per kg of body weight b. 2 g of tyrosine protein per kg of body weight c. 0.66 g of protein per kg of body weight d. 0.5 g of protein per kg of body weight e. 0.8 g of protein per kg of body weight 53. What percent loss of lean body mass is associated with decreased immunity, increased infection risk, increased muscle weakness, decreased wound healing, and 30% mortality risk? a. 5% b. 10% c. 20% d. 30% e. 40% 54. The indispensable amino acid with the lowest Recommended Daily Allowance is a. leucine b. valine c. histidine d. tryptophan e. threonine 55. What are the products from the action of pepsin?

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Chapter 06: Protein a. disaccharides b. amylose c. short-chain fatty acids d. large polypeptides, some oligopeptides and free amino acids e. glycerol and fatty acids 56. The oxidation of which amino acid results in the formation of succinyl-CoA as a by-product? a. leucine b. isoleucine c. methionine d. valine e. glutamine 57. Which of the following is not a condition associated with protein malnutrition? a. chronic reduced access to food or marasmus b. edematous malnutrition or kwashiorkor c. disease-related malnutrition d. intermittent fasting e. sepsis and trauma-related inflammation 58. Which process is NOT a source of ammonia in the body? a. urea formation in the liver b. deamination of amide groups from glutamine c. degradation of pyrimidines d. bacterial lysis of urea and amino acids in the GI tract e. complete oxidation of amino acids 59. Which two substances promote amino acid degradation? a. acetyl-CoA and dihydroxy acetone phosphate b. insulin and glucagon c. glucocorticoids and glucagon d. acetoacetate and acetaldehyde e. insulin and GLP-1 60. Which of the following statements is not true about protein turnover? a. Rate of protein turnover is equal in all tissues. b. Protein synthesis is high during growth. c. Protein degradation is high during illness and injury. d. Protein turnover accounts for 10-25% of resting energy expenditure. e. 1-2% of body protein is turned over each day.

61. In cases of stress and/or an inflammatory response, which functions are prioritized by the body? a. digestion and absorption b. wound repair and host defense

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Chapter 06: Protein c. respiration and excretion d. circulation and reproduction e. temperature regulation and excretion 62. Which regulatory peptides in the intestinal phase of digestion activate the release of pancreatic pro-enzymes? a. trypsinogen and trypsin b. cholecystokinin and secretin c. carboxypeptidase A and B d. elastin and chymotrypsin e. gastrin and lysozyme 63. Which organ serves as the primary site of amino acid metabolism? a. kidney b. muscles c. liver d. brain e. blood 64. Damage-associated molecular patterns (DAMPs) are released in response to which process? a. dehydration b. increased urinary output c. reduced intestinal motility d. inflammation e. starvation 65. Which of the following function to stimulate phagocytosis and activation of complement proteins? a. C-reactive protein b. orosomucoid c. serum amyloid A d. fibrinogen e. secretin

Indicate whether the statement is true or false.

66. The liver is the site for transamination of all amino acids. a. True b. False 67. Urea synthesis occurs in the liver and kidneys. a. True b. False 68. Under fasting conditions, one would expect to find large amounts of free ammonia in the bloodstream due to the breakdown of amino acids for energy. a. True

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Chapter 06: Protein b. False 69. Plant sources of protein in the diet include grains and grain products. a. True b. False 70. Desquamated mucosal cells present an endogenous source of amino acids to be digested and absorbed in the intestine. a. True b. False 71. The majority of amino acid absorption occurs in the distal ileum. a. True b. False 72. When BCAAs are catabolized to their corresponding keto acid in muscle, the nitrogen is transported directly to the kidney as glutamine. a. True b. False 73. Use of glutamine in cells increases significantly under hypercatabolic conditions like infection. a. True b. False 74. In addition to protein synthesis, the brain uses amino acids for the synthesis of other N-containing compounds such as neurotransmitters. a. True b. False 75. It is estimated that the intestine uses 30-40% of some of the essential amino acids absorbed from the diet. a. True b. False 76. Decrease in total body water is greater in males than females with age. a. True b. False 77. A mutation in the genetic code (i.e., DNA) could result in the wrong amino acid inserted into a given protein during synthesis, thereby potentially affecting the ability of the protein to function properly due to changes in its conformation. a. True b. False 78. Lysosomes are found in all mammalian cells. a. True b. False 79. Gender is the only factor that affects body composition.

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Chapter 06: Protein a. True b. False 80. Incomplete proteins are derived from foods of animal origin such as eggs, milk, cheese, meat, and fish. a. True b. False

81. Transamination and Deamination: What are these two reactions in amino acid metabolism (draw a diagram if that is helpful)? Why are they important? (Hint—transamination is important for two reasons; deamination, essentially one.)

How do different tissues factor into these reactions?

82. What is the role of the liver in amino acid metabolism? Discuss three actions that occur in the liver as amino acids from the portal vein enter the liver. Your answer should include the types of compounds that are synthesized and the metabolic reactions involved.

83. During fasting conditions, the circulating levels of glutamine and alanine are elevated—why is this? Hint: this question is focused primarily on the muscle, but also includes other tissues.

84. What is meant by protein turnover? What general types of protein compounds are made in cells via protein synthesis? How do amino acid catabolism and dietary amino acids factor into protein turnover?

85. Several companies are now enriching enteral and parenteral nutrition products with glutamine. What is the rationale for this procedure?

86. Explain why serum levels of ALT and AST are good indicators for trauma or disease, and specify which tissues relate to which aminotransferase.

87. Discuss three nitrogen containing non-protein compounds. Mention the location and function in the body.

88. Discuss the quality of proteins and the concept of mutual supplementation in meal planning.

89. Explain the fate of the carbon skeleton of amino acids if the nitrogen is removed. Address the conditions under which each set of reactions can occur.

90. Discuss inherited disorders in the context of how mutations in proteins affect metabolism. Use two examples from protein metabolism to illustrate the impact of this type of genetic disorder.

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Chapter 06: Protein Answer Key 1. b 2. e 3. d 4. a 5. c 6. c 7. d 8. b 9. e 10. a 11. a 12. c 13. c 14. c 15. d 16. b 17. b 18. d 19. a 20. c 21. b 22. d 23. d 24. c 25. d

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Chapter 06: Protein 26. c 27. b 28. c 29. d 30. e 31. c 32. b 33. d 34. a 35. a 36. d 37. b 38. d 39. c 40. b 41. d 42. c 43. a 44. c 45. d 46. b 47. a 48. c 49. d 50. a 51. b

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Chapter 06: Protein 52. c 53. a 54. d 55. d 56. c 57. d 58. a 59. c 60. a 61. b 62. b 63. c 64. d 65. a 66. False 67. False 68. False 69. True 70. True 71. False 72. False 73. True 74. True 75. True 76. False

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Chapter 06: Protein 77. True 78. False 79. False 80. False 81. Transamination: amino acid1 + ketoacid2 ⇔ ketoacid1 + amino acid2 e.g., alanine + α-ketoglutarate ⇔ pyruvate + glutamate This reaction is important for (1) providing a carbon skeleton from amino acids for energy (like pyruvate), and (2) synthesizing nonessential amino acids (like glu). You can view this reaction in the opposite direction as well, generating energy as α-ketoglutarate and a non-essential amino acid (ala).

Deamination: amino acid ==> α-ketoacid + NH3 e.g.,

glutamate ==> α-ketoglutarate + NH3

This reaction is important to get any NH3 generated from transamination into a form in which it can be used to synthesize urea and then be excreted by the kidney.

Most transamination occurs in the liver (gluconeogenesis) and some occurs in the kidney (gluconeogenesis), except for BCAAs, which undergo transamination in the muscle. Urea synthesis occurs in the liver. That said, remember that transamination and deamination can occur in many cell types, but the subsequent steps of gluconeogenesis (i.e., PEPCK, etc.) and urea synthesis are only in the liver/kidney and liver, respectively.

82. Synthesize proteins: This includes making the enzymes required by the liver and other hepatic proteins, as well as proteins that will be secreted into the circulation, like albumin and lipoproteins. Also included here is the synthesis of Ncontaining compounds (although these are not proteins per se, they are made from amino acids), such as glutathione, carnitine, and creatine.

•

• •

Catabolize amino acids: this involves transamination to produce carbon skeletons and glutamate. The carbon skeletons can be used for energy directly or to synthesize glucose (gluconeogenesis). Transamination also can be used to synthesize non-essential amino acids (from essential AAs or other NEAAs). The glutamate can be used as is, for other reactions, or simply as an intermediate to donate the amine group towards urea synthesis.

Some amino acids (BCAAs) are not metabolized by the liver and are simply left in the circulation unchanged.

Synthesize urea for disposal of ammonia.

83.

•

•

Generation of alanine from pyruvate – muscle sends the alanine to the liver where via gluconeogenesis it is converted to glucose. The liver in turn sends the glucose back to the muscle for more energy. In addition to providing glucose, alanine (like glutamine below) can be used as a means to transport nitrogen to the liver for its disposal as urea (muscle does not have the ability to synthesize urea). This is important, especially during fasting, when a lot of protein is used for energy and thus a lot of nitrogen is generated.

Following the generation of glutamate (via transamination), an additional amine group is added to glutamate to form glutamine, which can then be sent to the liver to dispose of the amine groups as urea. Urea is secreted by the liver into the circulation, where it goes to the kidney and is excreted in the urine.

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Chapter 06: Protein 84. Protein turnover means that our bodies are continuously breaking down proteins and making new ones in order to adapt to our ever-changing conditions and the fact that all proteins have a given life span. Amino acids from breakdown join dietary amino acids in the body pool and can be used to synthesize proteins or other nitrogen-containing compounds.

Enrichment: One way we favor synthesis over degradation is that the enzymes involved in synthesis have a lower Km compared to the enzymes involved in catabolism. So, when there are amino acids “lying around,” such as after protein degradation, the enzymes required to make new proteins out of them “win out” over the enzymes involved in catabolizing them. However, when there is an overabundance of amino acids (high concentration), then the synthesizing enzymes are saturated, and now the catabolizing enzymes can take over.

85. Glutamine is necessary for cells such as the gut mucosa and immune cells to support their rapid cell proliferation.

During times of trauma or infection, these cells need more glutamine than can be released by the muscle. Provision of glutamine in formula aids recovery.

86. ALT and AST are very active aminotransferases in liver and heart, respectively. Normal serum levels of these two enzymes are low because they act intracellularly. If liver cells have been damaged, ALT and other liver enzymes will be found in the blood in higher than normal concentrations. Similarly, if AST is elevated in blood, heart damage is indicated.

87. The answer can be any three: • • • • • •

Purine and Pyrimidines – Function in DNA and RNA as nucleotide bases Choline – Used to synthesize phospholipids and sphingomyelin Carnosine – Found in skeletal muscle and cardiac muscle; acts as buffer and antioxidant Creatine – Found in muscle as a storehouse of energy phosphate Carnitine – Found primarily in muscle; used in transport of fatty acids into mitochondria for oxidation Glutathione – Found in all cells and in plasma; acts as a major antioxidant

88. The answer should include: • • • • •

The quality of proteins is based on the content of indispensable amino acids available. In addition it also depends on the digestibility of the food.

Plant and animal foods differ in their quality and their digestibility. Limiting the quality of the protein consumed will result in protein inadequacy and effects thereof on growth and other functions.

There are complete and incomplete proteins.

Completeness does not have to be determined by a single food. Foods can be combined in such a way that they supply adequate amounts of all indispensable amino acids.

In mutual supplementation, foods that constitute a meal are picked in such a way that their amino acid patterns are complementary and thus the supply of indispensable amino acids is equivalent to a food that is complete.

89. The answer should include: • • • •

Deamination to remove the amino group.

The carbon skeleton can be used for different purposes depending on the status of the body. In some cells, such as muscle and in liver, amino acids are routinely catabolized to yield energy through oxidation.

Under conditions of starvation, the carbon skeleton can be used to yield acetyl CoA and from thereon to ketone bodies to serve as an alternate fuel.

Under starvation or low carbohydrate conditions, the carbon skeleton can be used for gluconeogenesis to

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Chapter 06: Protein •

provide a source of glucose for cells that depend on it.

Under conditions of excess energy, the carbon skeletons are utilized to synthesize fat for storage reserves.

90. The answer should include: • • • •

Protein synthesis begins with information contained in DNA. Gene corresponds to protein sequence.

Transcription and translation If there is a mutation in the gene sequence, it could result in an abnormality in the sequence of amino acids which could affect the structure of the protein. If the structure is affected, it could have an effect on the function of the protein. Loss or reduced functionality would have an impact on metabolism.

Many examples are discussed in the text. Any of them can be used here – PKU (error in Phenylalanine hydroxylase); Hartnup disease (affecting the Trp transporter); Blue Diaper Syndrome (t transporter); Orotic Aciduria (orotate phosphoribosyl transferase mutation)

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Chapter 07: Integration and Regulation of Metabolism and the Impact of Exercise

Indicate the answer choice that best completes the statement or answers the question.

1. Which of the following relies solely on glucose for energy? a. muscle b. liver c. red blood cells d. adipose tissue e. intestinal cells 2. Which of the following relies on fatty acids/glucose as the major fuel? a. muscle b. kidneys c. red blood cells d. brain e. intestinal cells 3. Which of the following stores large amounts of triacylglycerols? a. muscle b. liver c. red blood cells d. adipose tissue e. intestinal cells 4. Which of the following uses little glucose-6-phosphate and stores much glycogen? a. muscle b. liver c. red blood cells d. adipose tissue e. intestinal cells 5. Which of the following can adapt to using ketone bodies during prolonged energy deficit? a. muscle b. liver c. red blood cells d. adipose tissue e. brain 6. Which of the following regulatory hormones stimulates liver glycogenolysis and gluconeogenesis? a. growth hormone b. insulin c. norepinephrine d. leptin e. glucagon

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Chapter 07: Integration and Regulation of Metabolism and the Impact of Exercise 7. Which of the following regulatory hormones stimulates lipolysis and increases triacylglycerol uptake from VLDL specifically in muscle? a. growth hormone b. insulin c. norepinephrine d. cortisol e. glucagon 8. Which of the following regulatory hormones stimulates gluconeogenesis and glycogenolysis in the liver similar to glucagon? a. growth hormone b. insulin c. norepinephrine d. cortisol e. leptin 9. Which of the following regulatory hormones stimulates removal of glucose from the blood and anabolic reactions? a. growth hormone b. insulin c. norepinephrine d. cortisol e. leptin 10. Which of the following regulatory hormones produced from phenylalanine and tyrosine functions as a neurotransmitter and stress hormone? a. growth hormone b. insulin c. epinephrine d. glucagon e. leptin 11. What are the two compounds that connect the metabolism of carbohydrates, lipids, and proteins? a. citrate and oxaloacetate b. succinyl-CoA and malate c. pyruvate and acetyl-CoA d. CO2 and NADPH e. pyruvate and citrate 12. What is pyruvate converted into when the cellular energy status favors anabolic reactions? a. fructose b. glucose c. succinyl-CoA d. NADPH e. ATP

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Chapter 07: Integration and Regulation of Metabolism and the Impact of Exercise 13. Which of the following is a regulated enzyme in glycolysis? a. isocitrate dehydrogenase b. pyruvate dehydrogenase c. fructose-1,6-bisphosphatase d. phosphofructokinase e. phosphorylase kinase 14. Where does most of the fatty acid synthesis occur in humans? a. adipose tissue b. heart c. liver d. brain e. red blood cells 15. Which of the following amino acids is glucogenic in the postabsorptive state? a. taurine b. leucine c. alanine d. lysine e. isoleucine 16. The lack of which muscle enzyme causes glucose to be trapped when phosphorylated in the muscle? a. glucose-6-phosphatase b. glycerol-3-phosphatase c. 6-phosphoglycerate dehydrogenase d. glucokinase e. aldolase B 17. How long does it take for the postabsorptive state to evolve into the fasting state? a. 12-18 hours b. 18-48 hours c. 24-36 hours d. 36-72 hours e. over 72 hours 18. Amino acids from muscle breakdown provide the chief substrate for which metabolic process? a. glycolysis b. gluconeogenesis c. glycogenesis d. pentose phosphate pathway e. glycogenolysis 19. Which amino acid is considered purely ketogenic? a. methionine

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Chapter 07: Integration and Regulation of Metabolism and the Impact of Exercise b. histidine c. tryptophan d. leucine e. alanine 20. In which state does a protein-sparing shift in metabolism from gluconeogenesis to lipolysis occur? a. early fasting state b. fasting state c. starvation state d. fed state e. postabsorptive state 21. Why is the brain unable to use fatty acids for energy? a. It lacks enzymes for oxidation of fats. b. It lacks mitochondria. c. Glycerol cannot cross the blood-brain barrier. d. Fatty acids cannot cross the blood-brain barrier. e. It lacks carnitine for fatty acid transport into mitochondria.

22. Which of the following amino acids are used primarily by muscle during protein turnover? a. branched-chain amino acids b. aromatic amino acids c. basic amino acids d. acidic amino acids e. hydrophobic amino acids 23. Skeletal muscle accounts for what percentage of protein turnover? a. 10-15% b. 15-20% c. 20-25% d. 25-35% e. 40-50% 24. In which organ does urea synthesis occur? a. kidney b. spleen c. liver d. pancreas e. gallbladder 25. What amino acid plays an important role in controlling toxicity from ammonia released during amino acid catabolism by the glutamate dehydrogenase reaction? a. glutamine b. glycine

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Chapter 07: Integration and Regulation of Metabolism and the Impact of Exercise c. serine d. valine e. alanine 26. Which of the following describes a system involving messenger molecules that bind to target tissues, triggering a series of intracellular reactions leading to a metabolic response? a. endocrine system b. nervous system c. vascular system d. respiratory system e. circulatory system 27. An individual who has not eaten in five days will most likely have an elevated level of which hormone? a. insulin b. norepinephrine c. glucagon d. ACTH e. parathyroid hormone 28. Which hormone has the primary responsibility for directing energy metabolism in the fed state? a. growth hormone b. cortisol c. glucagon d. insulin e. glucagon 29. Under the influence of insulin, which of the following is stimulated? a. glycogenesis b. glycogenolysis c. phosphorylation of glycogen synthase d. phosphorylation of glycogen phosphorylase e. lipolysis 30. The excess of which of the following molecules are precursors for insulin’s stimulation of fatty acid synthesis? a. sucrose and maltose b. glucose and sucrose c. fructose and sucrose d. glucose and fructose e. galactose and lactose 31. Which cells synthesize the protein hormone adiponectin? a. muscle cells b. cells of adrenal medulla c. adipose cells

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Chapter 07: Integration and Regulation of Metabolism and the Impact of Exercise d. liver cells e. pancreatic acinar cells 32. After several weeks of starvation, what proportion of the energy needs of the brain is supplied by β-hydroxybutyrate and acetoacetate? a. one-fourth b. one-third c. one-half d. two-thirds e. almost all of the energy needs 33. What is the preferred source of energy used by muscles to spare protein during prolonged starvation? a. ketones b. glucose c. fatty acids d. amino acids e. glycogen 34. What is the term used to represent maximum oxygen consumption relating to exercise capacity? a. respiratory quotient b. VO2 max c. ATP-CP d. lactic acid system e. oxidative quotient 35. Which of the following describes the lactic acid system? a. aerobic metabolism b. anaerobic metabolism c. aerobic glycolysis d. anaerobic glycolysis e. anaerobic lipolysis 36. Which substances become the main fuel for high-intensity exercise lasting more than one hour? a. plasma fatty acids b. glucose and fructose c. glycogen and glucose d. ketone bodies e. pyruvate and lactic acid 37. How does training enhance the utilization of fat as the primary energy substrate during submaximal exercise? a. It enhances the activity of glycolytic enzymes. b. It enhances fatty acid oxidation inhibiting glucose uptake and glycolysis. c. It enhances glucose uptake. d. It decreases the activity carnitine acyltransferase.

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Chapter 07: Integration and Regulation of Metabolism and the Impact of Exercise e. It increases lipogenesis.

38. Which of the following conditions is attributed to a primary failure of the β-cells of the pancreas to secrete insulin? a. hyperinsulinism b. hyperglycemia c. hyperlipidemia d. hyperphosphatemia e. hypercalcemia 39. Carbohydrate loading is a dietary and exercise strategy used to maximize a. glycogenolysis b. glycolysis c. lipolysis d. glycogen storage in muscle and liver e. gluconeogenesis

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40. What is the precursor for synthesis of the glycerol moiety of triacylglycerol in adipose tissue? a. fatty acid b. pyruvate c. glucose d. phospholipid e. cholesterol 41. What proportion of the glucose-6-phosphate used to synthesize liver glycogen is obtained from intestinally absorbed glucose? a. 1/6 b. 1/4 c. 1/3 d. 2/3 e. 1/2 42. Malonyl-CoA plays a regulatory role in which two processes? a. glycogenesis and gluconeogenesis b. fatty acid synthesis and β-oxidation c. glycolysis and protein degradation d. gluconeogenesis and glycolysis e. glycogenesis and glycogenolysis 43. A deficiency in carnitine acyltransferase I (CAT I) could lead to interference with which of the following processes? a. glycolysis b. gluconeogenesis c. ATP production d. CO2 production e. lipogenesis

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Chapter 07: Integration and Regulation of Metabolism and the Impact of Exercise 44. Which 3-carbon intermediate of glycolysis is used as the substrate to synthesize glycerol for TAG formation in adipose tissue? a. dihydroxyacetone phosphate b. pyruvate c. glyceraldehyde-3-phosphate d. phosphoenolpyruvate e. 2-phosphoglycerate 45. Which component of the diet provides the majority of energy for ATP production? a. protein b. protein and lipid c. carbohydrate and protein d. carbohydrate and lipid e. lipid only 46. In humans, fatty acids cannot be used to synthesize glucose because we lack the enzymes needed to convert a. acetyl-CoA to lactate b. glycogen to acyl-CoA c. acetyl-CoA to pyruvate d. acyl-CoA to acetyl-CoA e. lactate to acetyl-CoA

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47. Which of the following TCA cycle compounds cannot be used as a gluconeogenic precursor? a. acetyl CoA b. alpha ketoglutarate c. succinate d. fumarate e. oxaloacetate 48. As an “amphibolic” pathway, what is the TCA cycle capable of in addition to participating in oxidative catabolism? a. It provides precursors for biosynthetic pathways. b. It functions in both hydrophilic and hydrophobic environments. c. It participates in digestive processes. d. It functions both inside and outside the mitochondria. e. It functions in muscle growth processes.

49. Following a carbohydrate-rich meal, skeletal and cardiac muscles express which protein on their cell surfaces? a. GLUT1 b. GLUT2 c. GLUT3 d. GLUT4 e. GLUT5

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Chapter 07: Integration and Regulation of Metabolism and the Impact of Exercise 50. Which GLUT protein is the only one whose function is dependent on insulin? a. GLUT1 b. GLUT2 c. GLUT3 d. GLUT4 e. GLUT5 51. Which of the following would the adipocytes of an individual with hypoglycemia have most difficulty producing? a. glycerol-3-phosphate b. acetyl-CoA c. acyl-CoA d. glucose-6-phosphate dehydrogenase e. glycogen 52. How can muscle and adipose tissue obtain glycerol-3-phosphate? a. gluconeogenesis b. glycolysis c. glycogenolysis d. glycogenesis e. lipogenesis 53. Only the glycerol portion of triacylglycerols can be converted into a. fatty acids b. alcohols c. protein d. glucose e. acetyl CoA

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54. The synthesis of which of the following would be disrupted in an individual with a deficiency of glycerol-3phosphate? a. fatty acids b. triacylglycerols c. acetyl-CoA d. glucose e. carnitine 55. Fatty acids with an even number of carbons are degraded exclusively into a. glucose b. fructose c. acetyl-CoA d. triacylglycerols e. pyruvate

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56. Which of the following strongly influences the timeframes assigned to each of the phases of an individual’s fed-fast

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Chapter 07: Integration and Regulation of Metabolism and the Impact of Exercise cycle? a. metabolic rate b. age c. gender d. ethnic background e. most recent meal 57. When glucose exceeds the glycogen storage capacity of the liver, what is the excess glucose converted to? a. pentose phosphates b. fructose c. glucose-6-phosphate dehydrogenase d. fatty acids and triacylglycerols e. lactate 58. What provides the majority of blood glucose during the postabsorptive state? a. hepatic glycolysis b. hepatic glycogenolysis c. renal gluconeogenesis d. hepatic gluconeogenesis e. hepatic glycogenesis 59. At rest, the brain uses what percentage of available energy? a. 5-10% b. 15-20% c. 20-25% d. 30-40% e. 50-65% 60. The metabolic fuel shifts associated with the starvation state are designed to spare which of the following substrates? a. protein b. carbohydrates c. lipids d. glycogen e. vitamins and minerals 61. What is one of the problems associated with the use of dietary supplements used to enhance athletic performance? a. They are difficult to obtain. b. There is little scientific evidence to prove that they are effective. c. There are many supplements that are considered to be performance enhancing. d. Advertising for these products is often based on research that the layperson has difficulty understanding. e. It is difficult to pick the one most suited to each individual.

62. In the postabsorptive and fasting states, what is the primary source of energy for the resting skeletal muscle? a. fatty acids

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Chapter 07: Integration and Regulation of Metabolism and the Impact of Exercise b. blood glucose c. cholesterol d. glycogen e. ketones 63. In an exercise such as an 800 m sprint, what proportion of energy is supplied by the anaerobic lactic acid system? a. 10% b. 25% c. 50% d. 75% e. 100% 64. How does creatine enhance muscle performance? a. It reduces the muscle’s oxygen requirement. b. It speeds up ATP utilization. c. It improves contractile performance and brings about hypertrophy. d. It helps to add more muscle fibers to the muscle. e. It increases VO2 max.

65. What is the aim of supplementation with proteins and amino acids in conjunction with resistance training? a. increasing muscle mass b. speeding up muscle contraction c. adding more muscle fibers to the muscle d. reducing reliance on oxygen e. increasing oxidative capacity

Indicate whether the statement is true or false.

66. Glycogenolysis occurs exclusively in the liver. a. True b. False 67. Most of adiponectin’s effects are targeted toward adipose tissue. a. True b. False 68. A fasted state is characterized by a marked increase in protein synthesis. a. True b. False 69. Acetyl-CoA is a significant metabolic junction for several pathways, including metabolism of carbohydrate, lipid, and cholesterol. a. True b. False

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Chapter 07: Integration and Regulation of Metabolism and the Impact of Exercise 70. Most regulatory enzymes act in a bidirectional manner. a. True b. False 71. Glucagon and insulin control metabolic pathways that reflect a fasting and fed state, respectively; the primary signal to initiate this hormonal control is the glucose concentration in the bloodstream. a. True b. False 72. During very prolonged starvation nearing death, the body shifts from using protein for energy to using fat stores. a. True b. False 73. Muscle supplies its own glucose for energy needs by first using glycogen stores, and then converting amino acids to glucose. a. True b. False 74. The Cori cycle would be active under anaerobic conditions, such as excessive muscle exertion. a. True b. False 75. All tissues prefer glucose first, and then fatty acids, to meet their energy needs. a. True b. False 76. Glutamine transport is increased during the fasting state. a. True b. False 77. The postabsorptive state evolves into the fasting state after 36-72 hours of no food intake. a. True b. False 78. Skeletal muscle has a greater ability to store glycogen than cardiac muscle. a. True b. False 79. Brain and red blood cells adapt to using ketones during starvation. a. True b. False 80. Carbohydrate loading is a dietary and exercise strategy aimed at maximizing glycogenolysis in muscle and liver. a. True b. False

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Chapter 07: Integration and Regulation of Metabolism and the Impact of Exercise

81. Compare the fuel sources and needs of cardiac and skeletal muscle. Also explore the differences between the two types of muscle.

82. Name the three systems that play a role in supplying energy during movement/exercise. Describe briefly how they supply energy and discuss the temporal relationship between them during prolonged exercise. Any figures should be completely labeled and explained.

83. Metabolic pathways are regulated to maintain homeostasis in the face of changing environmental conditions, such as nutrient supply. Describe how this is accomplished during the fed-fast cycle, that is, the progression from a fed state, to a postabsorptive/fasting state, to starvation, to prolonged starvation. Your answer should include specific processes/ metabolic pathways that are favored under each condition—make sure to cover pathways that are important to all three macronutrients (CHOs, lipids, protein). Also indicate the signal(s) involved in modulating these pathways. An example is provided in the table.

Fed ↑ glycolysis

Postabsorptive

Fasting

Prolonged Starvation

84. Pick two (2) of the examples from question 83 and indicate specifically how the signal you indicated in your answer is altering the pathway listed. For each example, write a one-sentence answer that includes the condition, the signals, the mechanism, the protein/enzyme, the tissue, and the result (all underlined in the example below).

Example: Under fed conditions, high blood glucose leads to insulin secretion by the pancreas, which in turn induces expression of the key glycolytic enzyme phosphofructokinase in all cells, thereby increasing glycolysis.

85. Discuss the brain’s sources of energy and adaptation to starvation.

86. In general, describe how opposing pathways are regulated during fasting versus fed conditions. What are the primary signals involved? What would be an example of two opposing pathways? How is one pathway favored over the other (you don’t need to name specific proteins/ enzymes here)?

87. Describe the four phases of the fed-fast cycle and include the time frames associated with each state.

88. The tricarboxylic acid cycle (TCA cycle) is used to produce ATP. It includes several intermediates that enter into anabolic pathways. List three of these intermediates and briefly describe their functions.

89. Describe the various functions of glucagon postabsorptive state that oppose the actions of insulin in the fed state.

90. What is the significant difference between energy metabolism in red blood cells and other cells of the body? How does the red blood cell overcome these differences?

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Chapter 07: Integration and Regulation of Metabolism and the Impact of Exercise Answer Key 1. c 2. a 3. d 4. b 5. e 6. e 7. a 8. d 9. b 10. b 11. c 12. b 13. d 14. c 15. c 16. a 17. b 18. b 19. d 20. c 21. d 22. a 23. d 24. c 25. a

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Chapter 07: Integration and Regulation of Metabolism and the Impact of Exercise 26. a 27. c 28. d 29. a 30. d 31. c 32. d 33. a 34. b 35. d 36. a 37. b 38. b 39. d 40. c 41. d 42. b 43. c 44. a 45. d 46. c 47. a 48. a 49. d 50. d 51. a

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Chapter 07: Integration and Regulation of Metabolism and the Impact of Exercise 52. b 53. d 54. b 55. c 56. a 57. d 58. b 59. c 60. a 61. b 62. a 63. c 64. c 65. a 66. True 67. True 68. False 69. True 70. False 71. True 72. False 73. False 74. True 75. False 76. True

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Chapter 07: Integration and Regulation of Metabolism and the Impact of Exercise 77. False 78. True 79. False 80. False 81. Answers should include • • • •

Both types of muscle can use glucose and fatty acids as a source of energy Both have GLUT4 as well as other GLUTs to take up glucose from blood during various states such as fed, or fasting Both types of muscle have access to fatty acids through the action of lipoprotein lipase on lipoproteins Differences between the two types of muscle include: o Cardiac muscle needs a fairly constant supply of energy; skeletal muscle needs are low at rest but increase during exercise o Skeletal muscle can cycle between anaerobic and aerobic energy systems for supply o Cardiac muscle has low glycogen capacity, but skeletal muscle has high capacity

82.

•

•

ATP-Phosphocreatine (PC) System – PC is a “storage” form of phosphate (in muscle) that can be used to generate ATP from ADP—quick energy for short bursts of exercise. Aerobic system – same as above, but now, in the presence of oxygen, we can take the pyruvate generated from glucose and/or glycogen and allow it to enter the TCA cycle to generate even more energy, rather than going to lactate. Also, this is ongoing along with other systems, but it becomes the major contributor later on. This system generates the most energy and also allows other sources of energy (e.g., fatty acids) to contribute more.

Lactic acid system – this is basically anaerobic glycolysis. We generate energy (ATP) from glucose or glycogen, but once we get to pyruvate, it goes to lactate rather than acetyl-CoA. [Students may imply that we get energy from lactate (which we can, if we use gluconeogenesis), but that is not what this is. It is simply glycolysis.] This system functions for a little longer than ATP-PC, but at the same time. The lactate system doesn’t merely take over when the ATP-PC is exhausted. Both operate simultaneously; it’s just that the contribution of one system is favored over the other as a function of time.

[If students redraw the graph in Figure 7.12 here to show the relationship between these systems and their contribution to meeting energy needs as a function of time, that is fine as long as it was appropriately drawn, labeled, and explained.]

83.

Fed ↑ glycolysis Signal: insulin (in response to high blood glucose) Increases in: Glycolysis

Postabsorptive Signal: glucagon (in response to low blood glucose) and epinephrine and cortisol Increases in: Glycogenolysis

Glucose uptake (via GLUT 4

Gluconeogenesis

Fasting Signal: glucagon (in response to low blood glucose) and epinephrine and cortisol Increases in: Lipolysis (glycogen stores are gone & need to spare body protein)

Prolonged Starvation Signal: glucagon (in response to low blood glucose) and epinephrine and cortisol Increases in: Gluconeogenesis Protein degradation (lipid

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Chapter 07: Integration and Regulation of Metabolism and the Impact of Exercise translocation) Urea synthesis Glycogenesis

Ketogenesis

stores are depleted; all that is left is body protein, including visceral sources)

Protein degradation Lipogenesis Lipolysis (a little) Protein synthesis 84. Many potential examples – Students should follow the format in the example and not leave out what cells or tissues in which the example was occurring or fail to mention the name of the enzyme.

One example: Under starvation conditions, low blood glucose levels lead to epinephrine secretion by the adrenal glands, which stimulates hormone-sensitive lipase in the adipocytes to increase lipolysis of stored triacylglycerols, thereby increasing the use of fatty acids to produce ATP. 85. Answer should include: • • • •

In the fed state, brain preferentially uses glucose from blood for its energy needs. Fatty acids cannot cross the blood-brain barrier and thus do not serve as a supply of energy.

During the postabsorptive state, liver’s supply of glucose to blood ensures that brain has the glucose it needs During fasting the brain still relies mostly on glucose in blood for energy.

In starvation, the increased rate of ketogenesis supplies the slowly adapting brain with an alternate supply of energy in the form of ketones that can cross the blood-brain barrier.

86. A fed state is characterized by high blood glucose, which results in the pancreas releasing insulin into the circulation.

Insulin promotes glucose uptake, glycolysis/TCA, glycogenesis, and lipogenesis by various mechanisms (including translocation, enzyme stimulation, enzyme induction, etc.). A fasted state is characterized by low blood glucose levels, resulting in the release of glucagon. Glucagon promotes gluconeogenesis, lipolysis, and glycogenolysis. Epinephrine also plays a role in this, but more so under exercise and stress conditions to promote glycogenolysis in muscle rather than fasting conditions.

For both fed and fasting, all of these pathways also regulate themselves in the sense that high concentrations of products (e.g., ATP, citrate, NADH) allosterically inhibit many enzymes involved in their production, whereas high concentrations of substrates (e.g., ADP, NAD) allosterically stimulate these same enzymes.

87.

• • • •

The fed phase begins after ingestion of a meal and is associated with secretion of insulin. This phase lasts about 3 hours.

The postabsorptive phase occurs between 3 and 18 hours following the meal and is associated with a rise in glucagon secretion.

The fasting phase occurs when no additional food is ingested after the initial meal and is associated with a continued rise in glucagon levels. This phase lasts from 18 hours to approximately 2 days.

The starvation phase, which is also called a long-term fast, occurs when the individual is deprived of food for longer than 2 days. At this point, the body is fully adapted and will survive for a variable length of time depending on factors such as body constitution, initial body weight (mass of stored fat), and other underlying factors relating to the individual’s health.

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Chapter 07: Integration and Regulation of Metabolism and the Impact of Exercise 88. Any three may be selected by the students. The following three examples may be used: • • •

Citrate: moves from mitochondria into the cytosol. There, it is acted upon by citrate lyase, which causes it to cleave into oxaloacetate and acetyl-CoA. The acetyl-CoA is used for fatty acid synthesis.

Malate: this is acted upon by NADP+-linked malic enzyme. This reaction may provide a portion of the NADPH required for reduction reactions in fatty acid synthesis.

Succinyl-CoA: this intermediate may combine with glycine in mitochondria to form ∆-aminolevulinic acid, which leads to heme synthesis.

89. Glucagon is a catabolic hormone and has an impact on blood glucose levels, and fatty acid synthesis. Insulin, on the other hand, is an anabolic hormone.

• • • • •

Glucagon inhibits glycogen synthesis in the liver and skeletal muscle. Insulin stimulates it.

Glucagon stimulates gluconeogenesis in the liver. Insulin inhibits it.

Glucagon inhibits fatty acid synthesis from glucose while insulin stimulates lipogenesis leading to increased triacylglycerol assembly for energy storage.

Glucagon stimulates lipolysis in adipose tissue while insulin inhibits it.

Glucagon promotes ketogenesis in liver while insulin inhibits it and promotes glucose uptake.

90.

• • •

Red blood cells have no mitochondria and hence rely exclusively on glucose as their energy source. Most other cells have mitochondria and are able to rely on glucose and fatty acids as a sources of energy.

Lack of mitochondria means that red blood cells must produce ATP via anaerobic glycolysis. This ensures that they are efficient in delivering the oxygen that they carry. Glycolysis is an inefficient means of producing ATP from glucose.

The red blood cell has no means to metabolize the lactate that is generated by anaerobic glycolysis and relies on the liver’s ability to use the lactate to synthesize glucose via gluconeogenesis.

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Chapter 08: Energy Expenditure, Body Composition, and Healthy Weight

Indicate the answer choice that best completes the statement or answers the question.

1. Body mass index (BMI) is one way to estimate a. appropriate weight for height b. actual body adiposity c. body fat distribution d. risk factors associated with obesity e. overall health

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2. Which of the following represents a BMI range considered to be healthy for most adult men and women? a. <18.5 b. 15–18 c. 18.5–24.9 d. >30 e. ranges are different based on gender 3. What is the BMI of a man who weighs 220 lbs. and is 6 feet tall? a. 54.9 b. 36.7 c. 29.9 d. 24.0 e. There is not enough information to calculate BMI 4. When using the reference man and woman figures for assessessment purposes, respectively, what percentage of body weight is fat? a. 10%, 20% b. 15%, 27% c. 30%, 40% d. 45%, 55% e. 17%, 47% 5. Which body component comprises more diverse tissues? a. lean body mass b. fat mass c. fat-free mass d. skinfold thickness e. adipose tissue 6. The ratio of carbon dioxide produced relative to oxygen consumed is known as what? a. respiratory quotient b. respiratory balance c. respiratory deficit d. respiratory ratio e. respiratory intake

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Chapter 08: Energy Expenditure, Body Composition, and Healthy Weight 7. Which of the following is TRUE regarding predictive equations? a. men and women use the same formulas b. RQ values are needed c. they tend to overestimate RMR in people with excess body fat d. is highly accurate e. Includes heat loss as well as heat of water vaporization in the calculation 8. Underwater weighing, a method used to determine body composition, is based on which principle? a. Lean body tissue is denser than adipose tissue. b. Adipose tissue is denser than lean body tissue. c. Adipose tissue is composed mostly of water. d. Body fluids are not being weighed using this method. e. Volume of the air in the lungs does not have to be accounted for using this method.

9. The generally accepted respiratory quotient (RQ) value for carbohydrate is a. 0.53 b. 0.70 c. 0.82 d. 1.0 e. 0.37

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10. Which of the following techniques for measuring body composition makes use of small exposures to radiation? a. MRI b. DEXA c. TOBEC d. BIA e. BMR 11. Bioelectrical impedance analysis, a method used to determine body composition, is based on which principle? a. Atomic nuclei behave like magnets when an external magnetic field is applied across the body. b. Adipose tissue is denser than lean body tissue. c. Electrical conductivity is greater in lean tissue than in adipose tissue. d. Fat-free mass is proportional to total body potassium. e. Oxygen consumption and carbon dioxide production can be easily measured.

12. Quantification of total energy expenditure may be calculated using a. neutron activation b. infrared light c. high-frequency ultrasonic energy d. the doubly labeled water method e. substrate oxidation

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13. Obesity is associated with increased risk for which of the following disorders?

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Chapter 08: Energy Expenditure, Body Composition, and Healthy Weight a. stunting, wasting b. stroke, sleep apnea c. osteoporosis, osteopenia d. hepatitis, tuberculosis e. anemia 14. Basal metabolic rate represents . a. the rate of energy expenditure that sustains basic life processes in all cells in the awake state b. the rate of energy expenditure when the body is at rest and no food has been eaten in 4 hours c. minimal energy expenditure over a period of 24 hours d. all energy expenditure except that is attributable to physical activity e. the metabolic response to food 15. The thermic effect of food represents the . a. BMR minus the energy used in physical activity b. decrease in food energy due to cooking c. increase in energy expenditure associated with the body’s processing of food d. body’s storage of food as fat for insulation e. A 35% increase in energy expenditure above BMR 16. Which of the following contributes the highest thermic effect of food? a. fats b. mixed diet with at least 50% carbohydrate c. carbohydrates d. proteins e. equal distribution of proteins, fats and carbohydrates 17. Thermogenesis is associated with . a. hydration status b. ingestion of food c. synthesis of fat d. metabolic response of food e. a large contribution of total energy expenditure 18. Thermoregulation refers to . a. alterations in metabolism to maintain body core temperature b. alterations in food energy due to cooking c. the increase in energy expenditure associated with the body’s processing of food d. the body’s storage of food as fat for insulation e. a metabolic response of food 19. When oxidized, which nutrient(s) provide(s) the lowest respiratory quotient? a. carbohydrate b. protein

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Chapter 08: Energy Expenditure, Body Composition, and Healthy Weight c. fat d. mixed diet e. carbohydrates and protein are equal 20. Which RQ would not be possible for an ordinary mixed diet of carbohydrate, protein, and fat? a. 0.85 b. 0.80 c. 0.75 d. 0.15 e. all would be possible 21. In a clinical setting, which RQ suggests that the patient is not using fat as a source of calories? a. <0.70 b. <0.80 c. <0.90 d. <0.60 e. 1.00 22. Which method of assessing energy expenditure requires the measurement of food intake? a. doubly labeled water method b. Harris-Benedict prediction equation c. Mifflin-St. Jeor equation d. estimated energy requirement equation e. IBW 23. Which of the following methods of estimating energy expenditure does NOT require knowledge of the individual’s age? a. doubly labeled water method b. Harris-Benedict prediction equation c. Mifflin-St. Jeor equation d. estimated energy requirement equation e. all require you know the age 24. Which of the following would best determine energy expenditure? a. basal metabolic rate b. resting metabolic rate c. urinary nitrogen excretion d. thermic effect of food e. thermoregulation 25. Which formula evolved directly from height-weight tables and provides guidance to determine overall mortality risks? a. BMI b. RQ c. Mifflin- St. Jeor

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Chapter 08: Energy Expenditure, Body Composition, and Healthy Weight d. Harris-Benedict e. IBW 26. Which is a recommended measurement to determine energy expenditure? a. basal metabolic rate b. resting metabolic rate c. urinary nitrogen excretion d. thermic effect of food e. IBW 27. The adjustments in metabolism necessary to maintain the body’s core temperature are referred to as a. thermoneutrality b. thermal effects c. thermal control d. thermoregulation e. BMR 28. A clustering of factors that occur together more often than expected on chance alone is a/an a. symptom b. syndrome c. disease d. condition e. incidence

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29. Central obesity, increased plasma fasting glucose, increased fasting plasma triglyceride, hypertension, and decreased plasma HDL cholesterol are associated with what disorder? a. diabetes b. insulin resistance c. metabolic syndrome d. Cushing’s disease e. hyperlipidemia 30. Which of the following hormones or molecules increases the urge to eat? a. leptin b. ghrelin c. adiponectin d. insulin e. obesogens 31. Which of the following may cause a persistent feeling of hunger in the presence of increased leptin levels? a. lack of leptin receptors b. ghrelin overproduction c. leptin resistance d. damage to the hypothalamus

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Chapter 08: Energy Expenditure, Body Composition, and Healthy Weight e. an increase in cholecystokinin 32. Which of the following is true regarding adiponectin? a. brief half-life in circulation b. suppresses appetite c. increases satiety d. increased ketones production e. adiponectin has no role in food intake 33. Why should a person with more than the average amount of body fat feel less hungry? a. increased body fat means increased leptin that suppresses hunger b. increased body fat means more stored calories c. increased body fat insulates causing increased body temperature d. increased body fat means more ketones are available for energy e. increased body fat means less ketones are available for energy 34. Where is insulin produced? a. stomach and duodenum b. β-cells of pancreas c. intestine d. white adipose tissue e. stomach 35. Where is leptin produced? a. white adipose tissue b. pancreas c. large intestine d. stomach and duodenum e. Small intestine 36. Which of the following is true regarding android and gynoid obesity? a. android can only happen in males, gynoid can only happen in females b. both represent fat accumulation around the mid section/stomach c. Android obesity is more strongly associated with disease risk d. Gynoid obesity is more strongly associated with disease risk e. Android is often referred to as pear-shaped 37. Difficulties in getting accurate calculations of RMR based on the various equations developed arise in which group of people? a. people with excess body fat b. people who are lean c. adolescents d. young adults e. elderly adults

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Chapter 08: Energy Expenditure, Body Composition, and Healthy Weight 38. In degrees Fahrenheit, how much of a change in body temperature both up and down is tolerable before death results? a. 10 up, 10 down b. 5 up, 10 down c. 10 up, 5 down d. 5 up, 5 down e. 10 up, 15 down 39. Diet-induced thermogenesis is also called a. basal metabolic rate b. resting metabolic rate c. thermal regulation d. thermic effect of food e. RMR

.

40. Heat stress is of the highest concern for which group of athletes? a. high school baseball players b. professional football players c. high school football players d. professional soccer players e. high school soccer players 41. Which of the following is NOT an ideal body weight formula? a. Hamwi b. Miller c. Broca d. Mifflin-St. Jeor e. Devine 42. The connection between body, weight, body fat, and health were recognized centuries ago by a. Hippocrates b. Socrates c. Galen d. Plato e. Hamwi 43. A person with a BMI of 31 would fall into what category? a. underweight b. healthy c. normal d. obese e. overweight 44. Which of the following would lower the metabolic rate?

.

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Chapter 08: Energy Expenditure, Body Composition, and Healthy Weight a. increasing physical activity b. increasing the rate of digestion c. cold environment d. reduction in sweating e. warm environment 45. What is the average PAL for a sedentary person? a. 1.0 b. 1.25 c. 1.75 d. 2.0 e. 2.5 46. Which of the following expends the greatest amount of energy? a. cross-country skiing at 8 mph b. vigorous, full-court basketball c. vigorous soccer d. running at 9 mph e. basketball 47. Which energy equation is used typically in clinical settings and can accurately predict RMR within 10% a. BMR b. Harris-Benedict c. Mifflin-St. Jeor d. Hamwi e. Weight-only 48. The 1846 height weight table published by John Hutchinson was based on what? a. 55-year-old men b. overweight men in England c. 30-year-old women d. 30-year-old men e. a mix of men and women 49. Which of the following is true regarding BMR and RMR? a. BMR is difficult to obtain in most people, whereas RMR is more easily measured b. BMR and RMR are virtually the exact same measurement c. RMR is more difficult to obtain than BMR d. RMR requires strictly controlled laboratory conditions e. BMR is measured when one is asleep 50. In what situation would leptin hormones increase? a. decreased adipose tissue b. starvation

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Chapter 08: Energy Expenditure, Body Composition, and Healthy Weight c. overfeeding d. between meals e. elevated blood glucose levels 51. Which of the following is true of BMR? a. represents the amount of energy needed to sustain basic life processes b. age and gender may affect it c. cold environments can increase BMR d. BMR increases during pregnancy e. all are true of BMR 52. Which of the following is NOT a strength of the Food Frequency Questionnaire? a. self-administered b. inexpensive c. is culturally sensitive d. machine readable e. Good for a large sample size 53. Which field method utilizes conductivity to measure fat vs. lean body mass? a. skin fold thickness b. underwater weighing c. BMR d. air displacement e. BIA 54. A twofold increase in risk for CVD, myocardial infarction, stroke, and CVD-related mortality is associated with what? a. an increase in leptin b. high LDL cholesterol levels c. metabolic syndrome d. lean body mass percentage e. Type 2 Diabetes

Indicate whether the statement is true or false.

55. Five sites commonly used for measuring skin fold thickness are the triceps, subscapula, suprailiac, abdomen, and thigh. a. True b. False 56. All individuals will experience a reduction in hunger if given leptin injections. a. True b. False 57. The doubly labeled water method enables the assessment of total body expenditure. a. True

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Chapter 08: Energy Expenditure, Body Composition, and Healthy Weight b. False 58. Heat released by metabolic oxidation can be measured by direct calorimetry. a. True b. False 59. Skinfold measurements should be repeated at least two-three times for the most accurate reading. a. True b. False

60. Discuss using growth charts in children, including what is needed to plot data.

Indicate whether the statement is true or false.

61. Because BMI has limitations, many health professionals also measure BMR. a. True b. False 62. The density of body fat is about 0.9g/mL, whereas the density of fat-free mass is about 1.1 g/mL. a. True b. False 63. Hormones that regulate appetite target the region of the hypothalamus known as the arcuate nucleus. a. True b. False 64. Adiponectin levels decrease with decreased fat mass and increase with increased fat mass. a. True b. False 65. Peptide YY is the only known orexigenic hormone. a. True b. False 66. Leptin decreases the urge to eat and increases physical activity to produce a negative energy balance. a. True b. False 67. Obesogens stimulate body fat accumulation by binding to hormone receptors and either stimulating or inhibiting the signaling pathway. a. True b. False 68. Type 2 diabetes is associated with very low or absent insulin. a. True

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Chapter 08: Energy Expenditure, Body Composition, and Healthy Weight b. False 69. Experts agree that moderate weight loss (5–10 kg) consisting of both fat mass and fat-free mass can be achieved by calorie restriction alone. a. True b. False 70. BMI can be used as an index to determine overall health. a. True b. False

71. Explain the difference between the different methods of determining what people eat, including pros and cons of each.

72. Explain the principles underlying the use of doubly labeled water to assess total energy expenditure. Include a discussion of the main source of error.

73. Define basal metabolic rate (BMR) and describe the percentage of energy used at rest by the liver, brain, kidneys, heart and skeletal muscle.

74. Explain the laboratory methods in determining body composition. Discuss the pros and cons of each one.

75. Which gland, and specifically, which region of that gland, controls appetite? Describe how hunger and satiety are achieved and which hormones are responsible for both.

76. Describe leptin’s association with white adipose tissue and explain why the body reacts to it as it does.

77. Describe metabolic syndrome and give the criteria for its clinical diagnosis.

78. What relationship does insulin resistance have to metabolic syndrome? What are the causes of these associations?

79. Explain why a high protein diet that includes a low carbohydrate intake and an average fat intake would lead to weight loss as long as the caloric intake did not exceed energy expenditure.

Indicate the answer choice that best completes the statement or answers the question.

80. Of the following statements, choose the one that is NOT true regarding anorexia. a. Of psychiatric disorders, anorexia has the highest mortality rate. b. People with anorexia simply restrict calories severely and never binge and purge. c. People with anorexia have a distorted body image and fear weight gain. d. People with anorexia often consume less than 800 kcal/day. e. People with anorexia often suffer from amenorrhea.

81. Which of the following is true regarding those with bulimia? a. is overly concerned with losing weight and being very thin b. seeks to eat without gaining weight c. is usually diagnosed with the female athlete triad

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Chapter 08: Energy Expenditure, Body Composition, and Healthy Weight d. characteristically experiences premature osteoporosis e. suffers from amenorrhea 82. Statistically, what percentage of individuals with anorexia nervosa recover completely? a. about 40-50% b. about 20-30% c. about 15-25% d. about 10-15% e. about 5-10% 83. Which psychiatric disorder is associated with the highest mortality rate? a. female athlete triad b. bulimia nervosa c. binge eating disorder d. anorexia nervosa e. eating disorders not otherwise specified 84. In order to determine disease risk, many health professionals use BMI and which other measurement? a. body temperature b. tibial length c. head diameter d. waist circumference e. scapular width 85. Physical activity typically accounts for what percentage of total energy expenditure? a. 10-20% b. 15-30% c. 20-35% d. 25-35% e. 45% or more 86. Historically, the gross anatomy and chemical composition of the human body were determined using what? a. athletes b. premenopausal women c. cadavers d. postmenopausal women e. neonates 87. Bioelectrical methods of determining the two-compartment model are based on a. capacitance b. resistance c. voltage d. impedance e. electrolytes

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Chapter 08: Energy Expenditure, Body Composition, and Healthy Weight 88. Respectively, the reference man and reference woman have what total percentage of body fat? a. 27%, 15% b. 18%, 28% c. 15%, 27% d. 12%, 28% e. 17%, 42% 89. The main target of hormones that regulate hunger and satiety is the a. medulla oblongata b. cerebellum c. hypothalamus d. thalamus e. cerebral cortex

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90. Receptors for which hormone are located in the hypothalamus, skeletal muscle, liver, and smooth muscle? a. adiponectin b. cholecystokinin c. pancreatic polypeptide d. GLP-1 e. leptin

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Chapter 08: Energy Expenditure, Body Composition, and Healthy Weight Answer Key 1. a 2. c 3. a 4. b 5. c 6. a 7. c 8. a 9. d 10. b 11. c 12. d 13. b 14. a 15. c 16. d 17. d 18. a 19. c 20. d 21. e 22. a 23. a 24. c 25. e

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Chapter 08: Energy Expenditure, Body Composition, and Healthy Weight 26. c 27. d 28. b 29. b 30. b 31. c 32. e 33. a 34. b 35. a 36. c 37. a 38. b 39. d 40. c 41. d 42. a 43. d 44. c 45. b 46. a 47. c 48. d 49. a 50. c 51. e

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Chapter 08: Energy Expenditure, Body Composition, and Healthy Weight 52. c 53. e 54. c 55. True 56. False 57. True 58. True 59. True 60. Growth charts for children were developed by the CDC to use in children from ages 2-20 years old. There are charts for both males and females and the height and weight, weight for age and height for age can all be plotted on growth curves to monitor the child’s growth. The BMI percentile can also be plotted, however they are different than the BMI numbers that adults use.

61. False 62. True 63. True 64. False 65. False 66. True 67. True 68. False 69. True 70. True 71.

The main ways to determine what people eat are food frequency questionnaire, 24- hour recall, food diary and diet history. Food frequency questionnaires are usable in large sample sizes, are inexpensive to collect and do not require prior training, some of the cons would be that it may not be culturally sensitive, it may offer incomplete lists of food or portion size choices and it relies on the ability of the person taking the survey. The 24-hour recall is useful because it is inexpensive, multiple days may be taken and it’s easy to administer, however, the limitations include that it relies on the participant’s memory, the participant may withhold information and data entry is cumbersome. The food diary is not dependent on memory and provides detailed food intake, however, it requires a high degree of cooperation from the participant, requires a literate participant and the act of recording may alter the intake. The diet history assesses food over

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Chapter 08: Energy Expenditure, Body Composition, and Healthy Weight a longer amount of time, assesses other lifestyle habits and can capture seasonal changes, however, it can be rather lengthy, requires highly trained interview staff and the data collection and analysis is expensive and time-consuming.

72. Doubly labeled water uses stable isotopes of both hydrogen and oxygen to assess the total energy expenditure over several days. The isotopes equilibrate with body water in about 5 hours. Labeled hydrogen leaves the body as labeled water in sweat, urine, and exhaled water vapor. Labeled oxygen leaves the body as labeled water or carbon dioxide. The disappearance of water with labeled oxygen and with labeled hydrogen is measured over time (usually 3 weeks). The disappearance of labeled hydrogen represents water turnover alone. Labeled oxygen, however, can leave as either water or carbon dioxide. Therefore, the difference in the disappearance of hydrogen-labeled water and oxygen-labeled water represents the oxygen leaving as carbon dioxide. The food quotient is measured by keeping a food record during the experimental period. Oxygen consumption can be calculated from the food quotient and the calculated carbon dioxide production. The main source of error is the inaccuracy associated with use of food records.

73. Basal metabolic rate (BMR) represents the amount of energy needed to sustain basic life processes such as respiration, heartbeat, renal function, brain and nerve function, blood circulation, active transport and synthesis of proteins and other molecules. Most of the energy used at rest is used by the liver (27%), brain (19%), kidneys (10%), heart (7%), and skeletal muscle (18%).

74.

The main ways to determine body composition by laboratory methods include densitometry which could be either underwater weighing or air displacement. Another method would be the DEXA also known as Dual-energy X-ray absorptiometry. The last method would be CT scans or MRI. Underwater weighing is considered a non-invasive and relatively accurate way to ensure body composition, however equipment cost is high and requires time and cooperation from the subject. Air displacement is suitable for populations that can not do the underwater weighing such as older adults or very young. A con would be that subjects must sit in a chamber ( which could be expensive) with a tight-fitting bathing suit and hair cap on for accurate computation. DEXA is considered the gold standard in diagnosing osteoporosis, is widely available, and entails low X-ray exposure. CT scans and MRI are more commonly available but require highly trained individuals to use them.

75. The gland that regulates appetite is the hypothalamus. The specific area of this gland is the arcuate nucleus, which contains specialized neurons. One population of neurons have hormone receptors that, when stimulated, release orexigenic peptides that stimulate appetite. These include neuropeptide Y (NPY) and agouti-related peptide (AgRP). The second population of neurons produces anorexigenic peptides that inhibit appetite. These belong to the pro-opiomelanocortin (POMC) family. These work in other areas of the hypothalamus as well as in other parts of the brain to curb appetite.

76. Leptin interacts with the hypothalamus to reduce hunger. It is produced by white adipose tissue. When leptin binds to its receptors, orexigenic neurons are inhibited and the production of NPY and AgRP is reduced. At the same time, anorexigenic neurons are stimulated to release POMC peptides. Studies have shown that when the amount of body fat increases, leptin levels increase as well. This suppresses hunger. Less body fat means less leptin resulting in a lower level of appetite suppression. This makes sense from a biochemical point of view as individuals with more body fat should eat less and those with lower levels of body fat should have the desire to eat more.

77. Metabolic syndrome is a group of risk factors that are associated with an increased risk of cardiovascular disease. The risk factors include central obesity, increased fasting plasma glucose, increased fasting plasma triglyceride, decreased plasma HDL cholesterol and hypertension. The criteria for the clinical diagnosis of metabolic syndrome will come from Table 8.7.

78. Insulin resistance is associated with excess body fat, elevated blood glucose levels, elevated triacylglycerols and high blood pressure. These conditions are the diagnostic criteria for metabolic syndrome. Insensitivity to insulin occurs primarily in muscle and adipose tissue. The muscle loses its ability to uptake glucose. Resistant adipose tissue is no longer inhibited from releasing free fatty acids. Liver and kidney do not exhibit insulin resistance. The liver is able to respond to

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Chapter 08: Energy Expenditure, Body Composition, and Healthy Weight the elevated insulin levels by synthesizing triacylglycerol from the excess free fatty acids, thus elevating fasting serum triacylglycerol levels. In addition, the elevated triacylglycerol levels in the liver lead to nonalcoholic fatty liver disease.

The kidney responds to elevated insulin levels by increasing renal sodium retention and decreasing uric acid clearance.

Essential hypertension develops due to a higher level of retained water.

79. The thermic effect of food plays an important role in this type of weight loss diet. Because protein in foods has the greatest thermic effect (20–30%), more energy will be expended in digesting these foods than would be expended digesting carbohydrates (5–10%) or fats (0–5%). Because the diet is low in carbohydrates, that portion of the energy Expenditure would be minimal. Also, since the energy expenditure for fats is so low, a normal fat intake would not use very much energy. All of these factors combined would lead to weight loss.

80. b 81. b 82. a 83. d 84. d 85. b 86. c 87. d 88. c 89. c 90. a

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Chapter 09: Water-Soluble Vitamins

Indicate the answer choice that best completes the statement or answers the question.

1. When vitamin C is consumed in excess of body needs, what happens to the excess? a. excreted in the feces b. stored in liver, bone, and adipose tissue c. excreted in the urine d. not absorbed e. stored in GI tract 2. What is a major function of B vitamins? a. antibodies b. a source of energy c. a part of a coenzyme d. electrolytes e. lipid storage 3. Most animals synthesize their own ascorbic acid from a. glucose b. glutamine c. glycogen d. alanine e. B vitamins

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4. How does ascorbic acid becomes dehydroascorbic acid? a. loses two electrons b. loses one electron c. gains two electrons d. gains one electron e. loses one electron, gains one electron 5. Vitamin C acts as a cofactor by maintaining iron in a reduced state in what? a. collagen synthesis b. methylation of homocysteine c. release of energy from nutrients d. red blood cell synthesis e. white blood cell synthesis 6. The organ that is most commonly used as a storage site for B vitamins is what? a. kidney b. heart c. brain d. liver e. lung

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Chapter 09: Water-Soluble Vitamins 7. Which water-soluble vitamin contributes to “intracellular cement” in the formation of scar tissue and wound healing? a. thiamin b. riboflavin c. vitamin C d. vitamin B12 e. biotin 8. Which B vitamin is involved in hematopoiesis (production of blood cells)? a. vitamin B12 b. vitamin B6 c. biotin d. vitamin B2 e. thiamin 9. Beriberi is a deficiency syndrome associated with what vitamin? a. vitamin B12 b. vitamin B1 c. vitamin B2 d. vitamin B6 e. vitamin c 10. Without enough vitamin C, what would happen to collagen? a. be too tightly coiled b. be overhydroxylated c. be underhydroxylated d. too strong and less flexible e. could not bond to each other 11. A primary function of vitamin C is to act as a/an what? a. antiviral agent b. antioxidant c. antirachitic agent d. acyltransferase e. transport molecule 12. Vitamin C’s actual participation in biochemical reactions usually involves its antioxidant ability. Choose the description of this activity. a. donates an electron or electrons to oxidize a mineral cofactor b. accepts an electron or electrons to reduce a mineral cofactor c. donates an electron or electrons to reduce a mineral cofactor d. accepts an electron from the quinone form of vitamin E e. donates an electron from the quinone form of vitamin E

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Chapter 09: Water-Soluble Vitamins 13. The necessity of ascorbic acid for its role in and are very tired. a. collagen synthesis b. creatine synthesis c. hormone activation d. carnitine synthesis e. electrolyte storage capabilities 14. The RDA for vitamin C for adult men is a. 75 mg; 500 mg b. 100 mg; 500 mg c. 90 mg; 2,000 mg d. 200 mg; 2,000 mg e. 1000 mg; 200 mg

is believed to be the reason that people with scurvy have no energy

and the UL is

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15. In what way are water-soluble vitamins absorbed? a. directly into the lymphatic system b. into the portal blood c. attached to proteins in the large intestine d. through the stomach wall into capillariess e. through the small intestine 16. What is a major role of thiamin? a. energy production b. blood coagulation c. collagen formation d. erythrocyte synthesis e. nutrient metabolism 17. Thiamin is important to fatty acid synthesis due to its requirement as a coenzyme for the pentose phosphate pathway enzyme called what? a. dopamine monooxygenase b. transketolase c. alpha-ketoglutarate dehydrogenase d. phenylalanine hydroxylase e. phosphorylation 18. Thiamin deficiency is known as what? a. pellagra b. megaloblastic anemia c. beriberi d. rickets e. scurvy

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Chapter 09: Water-Soluble Vitamins 19. Erythrocyte transketolase activity is an assay to assess the status of which vitamin? a. thiamin b. B6 c. riboflavin d. B12 e. Vitamin C 20. Riboflavin is found most often in what types of food? a. meats b. green leafy vegetables c. seafood d. milk and milk products e. citrus fruits 21. FMN and FAD act as prosthetic groups for enzymes called what? a. apoenzymes b. flavokinases c. bound enzymes d. flavoproteins e. tyrosine hydroxylase 22. Cheilosis is a symptom of a dietary deficiency of which vitamin? a. niacin b. ascorbic acid c. riboflavin d. biotin e. thiamin 23. When the diet is adequate in protein, the body can synthesize niacin from which amino acid? a. phenylalanine b. valine c. tyrosine d. tryptophan e. lysine 24. The best sources of niacin are a. fish and meats b. beans c. green leafy vegetables d. yellow vegetables e. citrus fruits

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25. Which classical vitamin deficiency is known for the four Ds: dermatitis, dementia, diarrhea, and death? a. thiamin

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Chapter 09: Water-Soluble Vitamins b. niacin c. biotin d. folic acid e. vitamin C 26. Which of the water-soluble vitamins is found widely distributed in all plant and animal foods, which makes a deficiency unlikely? a. riboflavin b. folic acid c. pantothenic acid d. pyridoxine e. biotin 27. Synthesis of coenzyme A starts with the phosphorylation of which vitamin? a. pyridoxal phosphate b. pantothenic acid c. vitamin E d. folic acid e. biotin 28. Hair loss associated with eating raw eggs may be reversed by treatment with what vitamin? a. niacin b. thiamin c. biotin d. ascorbic acid e. vitamin C 29. Decarboxylation of pyruvate is achieved by the interaction of pantothenic acid with thiamin, riboflavin, and which other vitamin? a. ascorbic acid b. vitamin B12 c. folate d. niacin e. biotin 30. A deficiency of which vitamin is associated with these symptoms: hallucinations, lethargy, skin rash, alopecia, and muscle pain? a. biotin b. thiamin c. vitamin C d. vitamin B12 e. riboflavin 31. Which vitamin deficiency results in megaloblastic anemia?

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Chapter 09: Water-Soluble Vitamins a. thiamin b. riboflavin c. vitamin c d. niacin e. folate 32. What foods would provide major sources of biotin? a. liver, soybean, eggs b. citrus fruits c. fish, meats, peanut butter d. green vegetables such as spinach and asparagus e. pork, sunflower seeds and legumes 33. Folate’s discovery resulted from the search to cure a. aplastic anemia b. hemolytic anemia c. Fanconi’s anemia d. megaloblastic anemia e. megaloblastic anemia

.

34. Which is folate absorbed? a. ileum b. duodenum, jejunum, colon c. proximal small intestine d. large intestine e. colon 35. Which agency establishes the DRIs? a. OSHA b. FDA c. Food and Nutrition Board d. USDA e. CDC 36. Methylation of DNA influences gene expression. Which vitamin is important in this process? a. niacin b. folate c. pantothenic acid d. riboflavin e. vitamin c 37. Folate and what other vitamin participate in the regeneration of methionine from homocysteine. a. niacin b. riboflavin

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Chapter 09: Water-Soluble Vitamins c. vitamin B6 d. vitamin B12 e. vitamin c 38. 5-methyl THF requires the action of which vitamin in order to form THF? a. B12 b. B2 c. niacin d. vitamin c e. folate 39. Burning foot syndrome may be caused by a deficiency of a. pantothenic acid b. ascorbic acid c. folate d. biotin e. vitamin C

.

40. Which of these statements is NOT true regarding water-soluble vitamins? a. absorbed into portal blood b. the excess is excreted in the urine c. not stored in large quantities in tissues d. deficiencies can occur e. must be taken as a supplement to get adequate amounts 41. Folate is vitally important for dividing cells during growth and cancer because of its essential role in the synthesis of . a. lipid bilayers b. mitochondria c. lysosomes and peroxisomes d. purines and pyrimidines e. collagen 42. Tetrahydrofolate is vitally important for dividing cells during growth and cancer and knowledge of this need is used in cancer treatment by giving the drug methotrexate to inhibit which enzyme? a. folylpolyglutamate synthetase b. dihydrofolate reductase c. formimino glutamate d. conjugase e. peroxisome 43. The last vitamin to be discovered was a. pantothenic acid

.

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Chapter 09: Water-Soluble Vitamins b. folate c. vitamin B6 d. vitamin B12 e. niacin 44. A cobalt deficiency may lead to . a. pellagra b. megaloblastic macrocytic anemia c. beriberi d. neurologic symptoms e. scurvy 45. Intrinsic factor is required for the majority of absorption of which vitamin? a. C b. B6 c. B12 d. B2 e. B7 46. Where is vitamin B12 absorbed? a. duodenum b. jejunum c. ileum d. colon e. large intestine 47. Which deficiency did sailors on sea voyages die of frequently? a. pellagra b. cheilosis c. megaloblastic anemia d. beriberi e. scurvy 48. Free pyridoxine is yielded by the action of a. acid phosphatase b. creatine phosphokinase c. lactate dehydrogenase d. alkaline phosphatase e. pyridoxamine

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49. Large amounts of folic acid can mask a vitamin B12 deficiency and prevent from resulting. Over time, the symptoms unique to a vitamin B12 deficiency will occur, and these are related to the . a. microcytic anemia; muscular system

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Chapter 09: Water-Soluble Vitamins b. DNA and RNA synthesis; vascular system c. one-carbon transfer; nervous system d. macrocytic anemia; nervous system e. collagen synthesis; vascular system 50. Which vitamin is most involved in amino acid metabolism? a. biotin b. vitamin E c. vitamin A d. vitamin B6 e. vitamin C

Indicate whether the statement is true or false.

51. Pellagra symptoms may appear during B6 deficiency because this vitamin is required in the process of obtaining niacin from tryptophan. a. True b. False 52. Unlike fat soluble vitamins, water-soluble vitamins are not stored, but readily excreted—the one exception is that we can store folate in the liver. a. True b. False 53. Pernicious anemia can be due to folate or B12 deficiency. a. True b. False 54. Fish are a major source of thiamin. a. True b. False 55. The primary role of vitamin C is as a reducing agent, particularly for the mineral component of a number of enzymes that becomes oxidized following catalysis of a reaction. a. True b. False 56. High circulating levels of homocysteine (i.e., hyperhomocysteinemia) have been implicated in a number of pathologies including cardiovascular disease. a. True b. False 57. Vitamin B6 deficiency is relatively rare in the United States. a. True b. False

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Chapter 09: Water-Soluble Vitamins 58. The water-soluble vitamins include a group of eight B-vitamins and vitamin C. a. True b. False 59. Impaired folding and secretion of proteins have been observed with riboflavin deficiency. a. True b. False 60. A deficiency of thiamin results in beriberi- which means “weakness”. a. True b. False 61. An example of a cleavage reaction requiring PLP is the degradation of thiamin in its pyrimidine and thiazole moieties. a. True b. False 62. Initial research on B6 was aimed at correcting dermatitis in rats. a. True b. False 63. Vitamin C’s antioxidant abilities may inhibit high-density lipoprotein (HDL) oxidation, which may diminish plaque formation associated with heart disease. a. True b. False

64. Although for micronutrients increasing the amount of a protein by directly inducing gene expression is certainly a common mechanism, we have encountered other mechanisms by which vitamins can regulate proteins. Give two examples of how posttranslational modification is involved in this—be as specific as possible.

65. What is the significance of vitamin C to carnitine and fat metabolism?

66. Discuss niacin equivalents and how they are calculated based on protein intake.

67. Explain the relationship of folate to vitamin B12 in the various anemias.

68. Describe the process by which vitamin B12 is digested and absorbed.

69. Describe how nutrients can be used to compensate for some gaps in our DNA.

Indicate the answer choice that best completes the statement or answers the question.

70. Which of the following is NOT true regarding DVs? a. The were last updated in January 2020. b. All vitamins and minerals have DVs.

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Chapter 09: Water-Soluble Vitamins c. Not all DVs are required to be listed on the nutrition label. d. Nutrition labels must include information about the vitamin D, C and B6. e. The DV is based on the highest of a nutrient’s RDA. 71. Which of the following foods offer the most Vitamin C in mg per serving? a. cabbage b. kiwi c. tomato juice (canned) d. banana e. grapefruit

72. Describe the difference between primary and secondary research.

Indicate the answer choice that best completes the statement or answers the question.

73. Which of the following is NOT true of observational research? a. can be descriptive or analytical b. can be cross-sectional c. can be case reports d. all descriptive research is observational e. are normally clinical trials 74. High concentrations of vitamin C are found in selected tissues including all EXCEPT which of the following? a. adrenal gland b. pituitary gland c. eyes d. brain e. red blood cells 75. What is the range of usual absorption of vitamin C from foods? a. 10-15% b. 15-25% c. 25-50% d. 60-70% e. 70-95% 76. Which enzyme helps vitamin C to maintain iron (Fe) in a reduced state? a. homogentisate dioxygenase b. tyrosine hydroxylase c. trimethyl lysine hydroxylase d. prolyl hydroxylase

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Chapter 09: Water-Soluble Vitamins e. peptidyl glycine 77. What happens to excess thiamin in the body? a. stored in liver b. toxicity occurs c. excreted through sweat d. excreted through urine e. stored in white blood cells 78. Individuals with alcohol dependency are more prone to developing which vitamin deficiency? a. thiamin b. niacin c. cobalamin d. riboflavin e. folate 79. Which form of beriberi occurs mostly in infants? a. chronic b. dry c. wet d. acute e. late onset 80. Brown Vialetto-Van Laere syndrome and Fazio-Londe syndrome are caused by what? a. niacin toxicity b. decreased intake of riboflavin in food c. excess excretion of hydrochloric acid d. mutations in the riboflavin transporter genes e. too much niacin 81. Which vitamin can be synthesized in the body from the amino acid tryptophan? a. vitamin C b. riboflavin c. thiamin d. cobalamin e. niacin 82. What of the following is NOT true of folic acid? a. most multivitamin preparations contain 400 ug of folic acid b. has only one glutamic acid attached to the PABA c. is very stable d. folic acid in supplements are absorbed at a lower rate than naturally occurring folate

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Chapter 09: Water-Soluble Vitamins e. s almost completely absorbed 83. Where is at least half of folate stored in the body? a. liver b. stomach c. white blood cells d. red blood cells e. large intestine 84. Why is folate and/or folic acid recommended to be taken periconception? a. to increase possibilities of multiple births b. to reduce risk of gestational diabetes c. to reduce risk of neural tube defects d. to reduce likelihood of miscarriage e. to increase fertility 85. How does the diuretic furosemide affect folate status? a. increases intestinal absorption b. decreases intestinal absorption c. no effect d. increases microvilli motility e. improves folate bioavailability

Indicate whether the statement is true or false.

86. Folate status is most often assessed by concentrations in the plasma, serum, or red blood cells. a. True b. False 87. Pernicious anemia is the lack of absorption of B12. a. True b. False

88. Indicate the active form of biotin, the general function of the vitamin and an example of the general function (specific reaction or pathway/process where it occurs).

89. Explain which nutrient was discovered based on the egg white injury, including symptoms and history of the vitamin.

90. Describe what (if any) role vitamin C has on the common cold.

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Chapter 09: Water-Soluble Vitamins Answer Key 1. c 2. c 3. a 4. a 5. a 6. d 7. c 8. a 9. b 10. c 11. b 12. c 13. d 14. c 15. b 16. a 17. b 18. c 19. a 20. d 21. d 22. c 23. d 24. a 25. b

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Chapter 09: Water-Soluble Vitamins 26. c 27. b 28. c 29. d 30. a 31. e 32. a 33. d 34. b 35. c 36. b 37. d 38. a 39. a 40. e 41. d 42. b 43. d 44. b 45. c 46. c 47. e 48. d 49. d 50. d 51. True

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Chapter 09: Water-Soluble Vitamins 52. False 53. False 54. False 55. True 56. True 57. True 58. True 59. True 60. True 61. False 62. True 63. False 64. With posttranslational modification (altering the function of an existing protein by forming a covalent bond without changing its abundance), pantothenic acid, as CoA, is involved in the acetylation of proteins. This means to “make a covalent bond” that consists of adding an acetate group (CH3COO-) to a protein to activate it.

Another PTM example is the role of vitamin C in collagen synthesis. Really, this should be called collagen modification—we are not increasing the synthesis of collagen, we are modifying its structure so that it can form crosslinks with other collagen molecules. Hydroxylation of the lysine or proline residues in collagen allows collagen to form cross-links (making it strong), and this process requires vitamin C. Vitamin C is not required directly in the hydroxylation step (which is why it is not considered a cofactor), but rather it is required to regenerate the enzyme that performs the actual hydroxylation. This enzyme contains Fe++ as a cofactor, which is oxidized to Fe+++ following the reaction; vitamin C functions to reduce the Fe+++ back to Fe++, thus allowing the enzyme to function again. Other vitamin C-dependent hydroxylation reactions are identical to this, with the exception that the substrate that is being hydroxylated is not a protein; thus, by definition it does not constitute posttranslational modification.

65. Grading rubric – answer should include the following items: Vitamin C functions as a reducing agent, specifically reducing the iron atom from the ferric state (Fe3+) back to the ferrous state (Fe2+) for the reactions catalyzed by trimethyllysine hydroxylase and 4-butyrobetaine hydroxylase in the synthesis of carnitine. The carnitine shuttle is required for fatty acid oxidation by allowing entry of long-chain fatty acids into the mitochondria for beta-oxidation.

66. Grading rubric – answer should include the following items: Assume that 1 g of complete, high-quality protein = 10 mg of tryptophan. This estimate means that an intake of 60 g of complete protein, for example, would provide 600 mg of tryptophan (10 mg tryptophan/1 g protein × 60 g protein = 600 mg tryptophan). Then, because it takes 60 mg of tryptophan to generate 1 mg of NE, 600 mg of tryptophan would generate 10 NEs (600 mg tryptophan × 1 mg NE/60 mg tryptophan = 10 NEs).

67. Grading rubric – answer should include the following items: Without vitamin B12, folate coenzymes are reduced to 5-

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Chapter 09: Water-Soluble Vitamins methyl folate (the methyl-folate trap) and cannot be converted to the coenzyme forms 10-formyl THF and 5,10-methylene THF, which are needed for synthesis of the purine ring and thymidylate, respectively. Consequently, DNA synthesis becomes deranged, along with cell differentiation and maturation, and this negatively impacts cells, especially those with rapid turnover such as blood cells. Megaloblastic, macrocytic anemia results.

68. Grading rubric – answer should include the following items: Ingested cobalamins are released from the proteins/polypeptides to which they are linked in foods through the actions of pepsin and hydrochloric acid in the stomach. Free vitamin B12 binds to an R protein that is found in saliva and gastric juice. Within the alkaline environment of the small intestine, the R protein is hydrolyzed by pancreatic proteases, and free vitamin B12 is released and binds to intrinsic factor (IF). The vitamin B12-IF complex travels from the duodenum to the ileum, where it interacts with a protein receptor (called cubilin, IF receptor, or cubam). Cubilin then interacts with another protein, amnionless, which facilitates cubilin’s attachment to the ileal cell’s plasma membrane. Binding of the vitamin B12-IF complex to the receptor triggers active endocytotic internalization. Vitamin B12 is absorbed throughout the ileum, especially the distal third. Within the enterocyte, the vitamin is released from the IF complex. Next, in or before it is transported across the ileum’s basolateral membrane, vitamin B12 binds to the protein transcobalamin II for transport in portal blood.

69. Individuals with a polymorphism that decreases activity of a folate-metabolizing enzyme, methylene tetrahydrofolate reductase, may have more elevated plasma homocysteine than those with a normal enzyme while more folate intake can normalize plasma homocysteine for those with this polymorphism.

70. d 71. c 72. Primary research produces original data by original investigators that design the study, collect and analyze the data then publish the results. Secondary research utilizes previously conducted information or data. In secondary research it is not the responsibility of the research to collect the data.

73. e 74. e 75. e 76. d 77. d 78. a 79. d 80. d 81. e 82. d

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Chapter 09: Water-Soluble Vitamins 83. a 84. c 85. b 86. True 87. True 88. Biotin is the active form of biotin, it is also known as vitamin B7. The general function of the vitamin is carboxylation.

The pathway for biotin is Acetyl-CoA carboxylase (FA synthesis), pyruvate carboxylase (gluconeogenesis), propionyl-CoA carboxylase (odd chain FA degradation/oxidation).

89. Biotin was discovered based on research investigating the egg white injury. Eating raw eggs was known to result in hair loss, dermatitis, and various neuromuscular problems. Biotin was found in the liver in 1931 and was found to cure the egg white injury. Biotin was once called vitamin H (the H refers to haut in Germain and means “skin.”

90. The common cold affects the average adult about two to six times each year and are caused most often by viruses.

Research has provided a theoretical framework for the use of vitamin C in the prevention and treatments of colds. Many studies have been conducted to examine the effectiveness of vitamin C and although studies have found no reduction in the incidence of colds while using vitamin C, there has been shown to be a reduction of colds by 50% by regular users of vitamin C among certain subsets of the population including athletes, and soldiers. Vitamin C supplementation has been shown to decrease the duration of cold symptoms in adults by 8% and children by 14%. Vitamin C supplementation has not been shown to be effective once cold symptoms are present.

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Chapter 10: Fat-Soluble Vitamins

Indicate the answer choice that best completes the statement or answers the question.

1. Which of the carotenoid pigments has the greatest provitamin A activity? a. alpha-carotene b. beta-carotene c. gamma-carotene d. delta-carotene e. beta-cryptoxanthin 2. Choose the food that is rich in vitamin A palmitate. a. spinach b. liver c. carrots d. pumpkin e. canned tomato juice 3.

Which molecule is this?

a. retinoic acid b. retinyl palmitate c. beta-carotene d. delta-carotene e. alpha-carotene 4.

Which is molecule is this?

a. alpha-carotene b. retinyl palmitate c. retinoic acid d. beta-carotene e. delta-carotene 5.

Which molecule is this?

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Chapter 10: Fat-Soluble Vitamins

a. alpha-carotene b. retinyle palmitate c. retinoic acid d. beta-carotene e. delta-carotene 6. The overall efficiency of the formation of retinal from beta-carotene is estimated at approximately what percentage? a. 20% b. 35% c. 50% d. 65% e. 75% 7. What happens to retinal in the enterocyte? a. It is esterified. b. It is reduced to retinol. c. It is transported into the portal blood. d. 15, 15' dioxygenase acts to form beta-carotene. e. It is stored as energy.

8. Choose the ONE correct statement. a. Beta-carotene is hydrolyzed in the jejunum before it is absorbed. b. Retinol does not need to form a micelle to cross the USW. c. Beta-carotene dioxygenase activity occurs in the lumen of the ileum. d. Retinol must be re-esterified to be carried in the chylomicron. e. Alpha-carotene is found in completely different foods than beta-carotene.

9. In order to be carried in the chylomicron, retinol (once in the enterocyte) is a. esterified by lecithin retinol acyl transferase b. converted to retinaldehyde by retinaldehyde reductase c. attached to a VLDL d. attached to an RXR receptor on the nucleus e. attached to pepsin

.

10. The majority of vitamin A is stored in the liver, while carotenoids are stored mainly in a. muscle b. eye c. adipose

what tissue.?

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Chapter 10: Fat-Soluble Vitamins d. skin e. muscle 11. In what cells will you find most of the retinol and vitamin A stored? a. stellate b. gallbladder c. fundus d. antrum e. white blood cells 12. How will retinol, once secreted from the liver, be found in the blood? a. attached to RBP and transthyretin b. attached to albumin c. attached to a chylomicron d. attached to RBP and stellate cells e. attached to WBC 13. A deficiency of vitamin A will lead to night blindness. This is due to what? a. damage to the retina b. inability to produce rhodopsin c. damage to the area of the brain that interprets incoming visual signals d. damage to the rods e. damage to the cornea 14. A deficiency of vitamin A, in addition to causing visual problems, might also lead to which of the following? a. muscular problems b. cardiovascular disease c. impaired height and improperly developed bones d. damage to the choroid layer of the eye e. type 2 diabetes 15. Vitamin A will work in conjunction with which vitamin to help protect cells from singlet oxygen? a. niacin b. thiamin c. pantothenic acid d. ascorbic acid e. biotin 16. Which diet has shown some promise in reducing the risk of progression to advanced macular degeneration? a. Paleo b. Mediterranean c. Atkins

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Chapter 10: Fat-Soluble Vitamins d. gluten free e. ketogenic 17. Within the nucleus, all trans-retinoic acid and/or 9-cis retinoic acid bind to a. nuclear retinoic acid receptors b. mannosylated glycoproteins c. cell aggregates d. transcription factors e. micelles

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18. Nausea, vomiting, double or blurred vision, headaches, vertigo, and muscle incoordination are symptoms of what? a. hypervitaminosis A b. hypervitaminosis D c. hypervitaminosis K d. hypovitaminosis A e. hypovitaminosis D 19. Which vitamin directs cellular differentiation of epithelial cells? a. riboflavin b. vitamin K c. vitamin E d. vitamin A e. vitamin D 20. Where would you find retinoid X receptors (RXR)? a. in cytosol b. in the nucleus c. in mitochondria d. in the Golgi apparatus e. in micelles 21. Which vitamin is said to be essential for growth and immune system function? a. K b. A c. D d. E e. niacin 22. Which is NOT related to the functions of vitamin A? a. neurological function b. growth c. immunity d. cell differentiation

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Chapter 10: Fat-Soluble Vitamins e. gene expression 23. Choose the correct statement about the quenching of singlet oxygen by carotenoids. a. Carotenoids donate an electron to the singlet oxygen to make it stable. b. Carotenoids covalently bond with the singlet oxygen to make it stable. c. Carotenoids donate energy so that the excited electron returns to its orbital. d. Carotenoids absorb the extra energy that is held by the singlet oxygen. e. Carotenoids absorb the singlet oxygen to give to the excited electron.

24. Which is the strongest antioxidant? a. beta-carotene b. alpha-tocopherol c. beta-cryptoxanthin d. lycopene e. alpha-carotene 25. Would you recommend β-carotene supplementation to a smoker to decrease the risk of lung cancer? a. Yes—β-carotene can quench singlet oxygen. b. Yes—smoking increases free radical formation; β-carotene can decrease free radicals. c. No—β-carotene supplements may be harmful to smokers and their use is not advised for the general public. d. No—β-carotene supplements can cause vitamin A toxicity and liver cirrhosis. e. No—β-carotene is not bioavailable in supplement form.

26. Imagine you are a nutritionist working in a country other than the United States. Which is an assumption about vitamin D status that is NOT true? a. The latitude makes a difference in regard to how much vitamin D can be self-synthesized. b. Customs of dress make a difference in regard to how much vitamin D can be self-synthesized. c. Cow’s milk is a reliable source of vitamin D in the food supply. d. Skin color makes a difference in regard to how much sun is needed to synthesize vitamin D. e. Rickets is still a problem one might encounter.

27. Which vitamin D molecule would you expect to see in fortified foods? a. ergocalciferol—vitamin D2 b. calcidiol—25-OH D3 c. calcitriol—1,25-OH2 D3 d. cholecalciferol—vitamin D3 e. 7-dehydrocholesterol 28. Calcitroic acid and vitamin D metabolites are excreted primarily through a. urine b. sweat c. urine and sweat combined d. feces

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Chapter 10: Fat-Soluble Vitamins e. they are stored indefinitely in cells 29. What percentage of vitamin D from the diet is absorbed? a. 20% b. 30% c. 40% d. 50% e. 75% 30. Dietary cholecalciferol must be further hydroxylated in order to be active vitamin D. The first hydroxylation occurs in the to produce . a. liver; 25-hydroxycholecalciferol b. kidney; 25-hydroxycholecalciferol c. skin; 7-dehydrocholesterol d. kidney; 1-hydrocholesterol e. kidney; 7-dehydrocholesterol 31. Vitamin D is derived from which structure? a. a steroid b. an amino acid c. a fatty acid d. calcium e. a lipid ring 32. Which vitamin is considered to be a secosteroid? a. choline b. vitamin A c. vitamin D d. vitamin E e. vitamin K 33. The best source of vitamin D per recommended serving is which of the following? a. liver b. tuna fish c. swordfish d. cod liver oil e. green leafy vegetables 34. The vitamin D response element (VDRE) is found a. on the enterocyte membrane b. on the renal tubule c. in the nucleus d. in the pancreatic duct cell

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Chapter 10: Fat-Soluble Vitamins e. in the lumen 35. Which vitamin has as its primary function the maintenance of calcium homeostasis? a. A b. D c. E d. K e. biotin 36. Where does the largest amount of absorption of vitamin D occur? a. jejunum b. ileum c. duodenum d. cecum e. colon 37. What vitamin is associated with diminished proliferation and enhanced differentiation of cells, which serves as a basis for its use as treatment of skin diseases such as psoriasis? a. A b. E c. K d. D e. niacin 38. The RDA for vitamin D for people over the age of 70 is how many times greater than that for adolescents? a. 2.0 b. 1.33 c. equal d. 0.75 e. 3.0 39. If asked about the relationship of vitamin D to autoimmune disease, the best information for a dietetic professional to provide is which of the following? a. that the evidence does not support a relationship at this time b. that the evidence is only in animals, not humans c. that some evidence suggests a protective effect of vitamin D d. to take a supplement containing 2000 IU vitamin D each day e. that supplemental vitamin D does not provide bioavailability 40. A deficiency of which vitamin is commonly associated with rickets? a. A b. D c. E

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Chapter 10: Fat-Soluble Vitamins d. K e. thiamin 41. Which tocopherol form of vitamin E has biologic activity? a. alpha b. beta c. gamma d. delta e. all forms have biologic activity 42. How does alpha-tocopherol differ from beta-tocopherol? a. saturation of side chain b. number and location of methyl groups c. source in the diet d. ionic versus covalent bonding e. absence of methyl groups 43. Who discovered vitamin E? a. Evans and Bishop b. McCollum and Davis c. Mellanby and Hopkins d. Simon and Garfunkel e. Jim Hutchinson 44. Most of the vitamin E in the blood is carried by what? a. water b. albumin c. hemoglobin d. LDLs and HDLs e. plasma 45. Immediately following a balanced meal that containsvitamin E (such as fortified milk), where would you most likely find most of the vitamin E in the body? a. in the portal blood as α-tocopherol b. inside cells as free α-tocopherol c. stored in adipose tissue d. in chylomicrons in the lymphatic vessels and general circulation e. stored in lean body tissue 46. For which vitamin is the Tolerable Upper Intake Level set because of increased tendency for bleeding? a. A b. D c. E

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Chapter 10: Fat-Soluble Vitamins d. K e. niacin 47. Vitamin D metabolites that are in excess of the body’s needs are primarily excreted how? a. excess is stored indefinitely b. through respiration c. through bile in the feces d. urine e. sweat 48. What deficiency is characterized by reductions in the mineralization of the bone’s growth plates? a. blood b. nyctalopia c. xerophthalmia d. beriberi e. rickets 49. Which of the following is true of calcitriol and the kidneys? a. inhibits the formation of the active form of vitamin K b. interferes with micelle formation such that vitamin K is not absorbed c. does not allow calcium to interact with Gla residues d. stimulates osteocalcin synthesis e. induces calcium reabsorption from the glomerular filtrate into the distal tubules of the kidneys 50. What is the primary function of calcitriol? a. promote osteoblast formation b. convert D2 into D3 c. convert sunlight into a usable source d. decrease serum calcium concentrations e. raise serum calcium concentrations

Indicate whether the statement is true or false.

51. Absorption of vitamins A, D, E, and K is closely associated with the absorption and transport of ingested proteins. a. True b. False 52. Because β-carotene can be converted into retinol, plant sources are referred to as preformed vitamin A. a. True b. False 53. Production of active vitamin D requires skin, sunlight, cholesterol, the liver, and the kidneys. a. True

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Chapter 10: Fat-Soluble Vitamins b. False 54. Calcium homeostasis in the blood depends on intestinal absorption, bone resorption, and kidney reabsorption. a. True b. False 55. Many anticoagulants inhibit the vitamin K cycle, thereby preventing activation of clotting proteins. a. True b. False 56. All three forms of vitamin A (retinol, retinal, and retinoic acid) are stored in the liver as retinyl esters. a. True b. False 57. Vitamin D increases the abundance of calbindin (Ca++ transporter) in enterocytes by increasing the transcription of the calbindin gene. a. True b. False 58. Rhodopsin is simply the opsin protein after it has been activated by 11-cis-retinal. a. True b. False 59. Many anticoagulants work by inhibiting the regeneration of active vitamin K (i.e., dihydrovitamin KH2) during the vitamin K cycle. a. True b. False 60. Vitamin A is metabolized as part of the visual cycle. a. True b. False 61. Cholecalciferol is also known as D3. a. True b. False 62. Vitamin D’s target tissues are very limited. a. True b. False 63. Most vitamin D supplements are providing the D3 form. a. True b. False

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Chapter 10: Fat-Soluble Vitamins 64. Vitamin A deficiency is less common in the US than in developing countries. a. True b. False 65. Excess vitamin A intake interferes with vitamin K absorption. a. True b. False

66. Indicate: (1) the active form of vitamin K, (2) the general function of vitamin K, and (3) an example of the general function (this could be a specific reaction or simply indicate a pathway/process where it occurs). Your answers do not need to be long!

67. Regulation of Proteins by Vitamins: Micronutrients, such as vitamins, typically regulate gene expression (i.e., induction) directly. Use either vitamin D or vitamin A to illustrate this concept—be complete and thorough in your answer. Do not simply draw a diagram; include some discussion and make sure everything is labeled and/or defined.

68. Although for micronutrients increasing the amount of a protein by directly inducing gene expression is certainly a common mechanism, we have encountered other mechanisms by which vitamins can regulate proteins. Provide one example of posttranslational modification, being as specific as possible.

69. Explain the process by which rhodopsin is formed.

70. Discuss the role of calcitonin in maintaining normal blood calcium concentration.

71. Why are vitamins A and E said to be antagonists of vitamin K? 72. In what populations would varying recommendations of Vitamin D be appropriate?

73. Explain the role that carotenoids have in heart health.

74. Describe the absorption and digestion issues associated with vitamin A. 75. List the fat-soluble vitamins and describe the best food sources for each one.

Indicate the answer choice that best completes the statement or answers the question.

76. What are the phases for reactions involving free radical reactions? a. initiation, propagation, termination b. initiation, termination c. initiation, propagation, regeneration d. propagation, regeneration, termination e. termination, propagation, regeneration 77. Which of the following is NOT true regarding fat-soluble vitamins? a. fat-soluble vitamins include A, D, E, K, and carotenoids

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Chapter 10: Fat-Soluble Vitamins b. fat-soluble vitamins are closely associated with the absorption and transport of ingested lipids c. digestion and absorption are greatest when some dietary fat is present d. absorption occurs most rapidly from the duodenum and jejunum e. fat-soluble vitamins are only found in foods with fat in them 78. Impaired vitamin D absorption may occur secondary to which of the following diseases? a. Crohn’s disease b. type 2 diabetes c. scurvy d. cancer e. gout 79. Which fat-soluble vitamin is most likely to cause toxicity? a. A b. D c. E d. K e. C 80. Which vitamin is also found in many creams designed for topical use? a. A b. D c. E d. K e. niacin 81. Which fat-soluble vitamin appears to be one of the least toxic? a. A b. D c. E d. K e. C 82. Which population is at an increased risk for vitamin E deficiency? a. premature infants b. toddlers c. the elderly d. post-menopausal females e. body builders 83. What are anticoagulants typically prescribed for? a. those at risk for type 2 diabetes b. to act as an antioxidant

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Chapter 10: Fat-Soluble Vitamins c. to reduce risk of thrombotic events such as a heart attack d. to reduce free radicals e. to promote bone growth in infants 84. Which of the following is NOT true regarding the vitamin K cycle? a. it ensures the availability of the vitamin in the form needed for Gla production b. the epoxide form of the vitamin must be re-converted back to the vitamin K dihydroquinone c. the cycle includes four forms of vitamins d. no ATP is required e. the dihydroquinone form of vitamin K is converted to vitamin K 2,3 epoxide 85. Which of the following is true regarding the FDA and vitamin K? a. the vitamin K content of foods is not required to be listed on labels unless it is fortified with the vitamin b. all vitamin K must be listed on the label c. the FDA has nothing to do with nutrition labels d. vitamins are not listed on nutrition labels e. only natural (non-fortified) vitamin K must be listed 86. Which of these foods provide the greatest amount of vitamin K per serving? a. collards b. pumpkin c. lettuce d. margarine e. pine nuts 87. For which vitamin discovery did Dam and Doisy win a Nobel prize in medicine for in 1941? a. vitamin E b. vitamin C c. vitamin K d. vitamin A e. biotin 88. What are the best food sources for vitamin E? a. meat and dairy b. citrus fruits c. plants and nuts d. egg whites e. sunshine 89. The generation of reactive oxygen species (ROS) starts with the uptake of what? a. carbon dioxide b. nitrogen

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Chapter 10: Fat-Soluble Vitamins c. H2O d. oxygen e. neutrophil 90. RDAs and Uls have been established for all fat-soluble vitamins except which one? a. A b. D c. E d. K e. niacin

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Chapter 10: Fat-Soluble Vitamins Answer Key 1. b 2. b 3. b 4. c 5. d 6. c 7. a 8. d 9. a 10. c 11. a 12. a 13. b 14. c 15. d 16. b 17. a 18. a 19. d 20. b 21. b 22. a 23. d 24. d 25. c

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Chapter 10: Fat-Soluble Vitamins 26. c 27. d 28. d 29. d 30. a 31. a 32. c 33. d 34. c 35. b 36. a 37. d 38. b 39. c 40. b 41. a 42. b 43. a 44. d 45. d 46. c 47. c 48. e 49. a 50. a 51. False

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Chapter 10: Fat-Soluble Vitamins 52. False 53. True 54. True 55. True 56. False 57. True 58. True 59. True 60. True 61. True 62. False 63. True 64. True 65. True 66. Vitamin K (1) Dihydrovitamin KH2 or hydroquinone (2) Carboxylation (3) Activation of clotting proteins (prothrombin to thrombin); activation of bone proteins (osteocalcin) 67. As stated, we are talking about induction—that means we are increasing the abundance of a particular protein by increasing gene expression.

Two good examples of this are vitamin D and vitamin A. Induction means an increase in the amount of the protein.

Micronutrients such as vitamin A and vitamin D accomplish this by directly increasing the transcription of a given gene.

A good example for vitamin D is its ability to increase the number of calcium transporters in the intestinal cell. It does this by binding in the cytosol to a vitamin D-binding protein (VDBP), which delivers it to the nucleus. In the nucleus, another protein, the vitamin D receptor (VDR), binds vitamin D and a second protein, the retinoid X receptor (RXR), binds to them. Collectively, this complex (VDR-RXR) can then bind to the vitamin D response element (VDRE) located in the promoter region of the gene that encodes for calcium binding proteins. When the VDRE is activated by the VDRRXR complex, it increases the transcription of calcium binding proteins; thus, there are more calcium binding proteins made in the cell and more calcium is transported in.

You can discuss a very similar scenario for vitamin A (i.e., retinoic acid). You have cytosolic proteins (CRABP) to take the retinoic acid to the nucleus, where it binds to a retinoic acid receptor (RAR) and then RXR. Together, they (RAR-RXR) bind to the retinoic acid response element (RARE) located on specific genes (such as the gene encoding for growth

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Chapter 10: Fat-Soluble Vitamins hormone receptor) to increase the transcription of that gene; thus, more protein, like growth hormone, is made.

Remember that regulation of gene expression by vitamin D and vitamin A is cell type-specific depending on the protein that is being induced. For calcium-binding proteins, this occurs in the enterocyte, but not other tissues. For growth hormone, this will occur in certain brain cells, but nowhere else. We don’t produce growth hormone and calciumbinding proteins in every cell that is exposed to vitamin A or D. Also, remember that once the expression of a gene is turned on, that results in making more mRNA corresponding to that gene (via transcription), and then the mRNA leaves the nucleus—it is translated into the desired protein.

68. A possible example is vitamin K, which is required for the carboxylation of a number of proteins involved in coagulation (e.g., prothrombin to thrombin) to make them more active. It also covalently modifies bone proteins. In both cases, the carboxylation of glutamate residues in the protein allows the protein to bind Ca++, thus making it more active in coagulation or bone formation.

69. Grading rubric – answer should include the following items: For vision to occur, 11-cis retinol must bind to the visual pigment opsin in the rods of the retina to form rhodopsin.

Subsequently when light hits the retina, the energy from the light splits opsin from rhodopsin and releases vitamin A as all-trans-retinal. This reaction is called bleaching because loss of rhodopsin decreases pigment color. The reaction sets off a cascade of reactions involving a G protein called transducin, causing the rod to hyperpolarize from blockage of sodium channels, which in turn sends signals through the optic nerve to the brain. To finish the cycle, all-trans-retinal is reconverted in a series of steps to 11-cis retinol and reunited with opsin to reform rhodopsin.

70. Grading rubric – answer should include the following items: Calcitonin is released from the thyroid parafollicular cells in response to elevated serum calcium and functions to restore serum levels back down to normal. Calcitonin inhibits osteoclasts, thus diminishing the release of calcium and phosphorus from bone and it stimulates osteoblasts. It diminishes kidney reabsorption of calcium and phosphorus and promotes excretion of calcium and phosphorus in urine.

71. Grading rubric – answer should include the following items: Excess intake of vitamins A and E interfere with absorption of vitamin K. In addition, vitamin E interferes with metabolism of MK-4 and may increase degradation of all forms of vitamin K in the liver.

72. Grading rubric – answer should include the following items: Because vitamin D is a fat-soluble vitamin and is sequestered in adipose tissue, obese individuals may require two to three times the recommended dose to prevent and/or treat deficiency. In addition, any individual who suffers with a malabsorption syndrome or who is taking medications that interfere with vitamin D metabolism should take higher doses of the vitamin to avoid deficiencies.

73. Grading rubric – answer should include the following items: Carotenoids have been shown in vitro to reduce/prevent the oxidation of LDL and cell membrane lipids. Increased blood concentrations of reactive oxygen and nitrogen species promote LDS oxidation and cell membrane lipid oxidation, factors that contribute to the development of atherosclerosis However, supplements with carotenoids have not been shown to prevent or improve heart disease in most studies and is not recommended.

74. Grading rubric – answer should include the following items: Vitamin A requires some digestion before it can be absorbed from the small intestine. Heating plant foods weakens some complexes and enzymatic digestion is still required. Because of their fat solubility, retinyl esters and carotenoids typically coalesce, along with other lips, to form fat globules in the stomach, which are then emptied into the duodenum where bile emulsifies them.

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Chapter 10: Fat-Soluble Vitamins 75. Vitamin A - food sources are liver, dairy products, and fortified foods as well as sweet potatoes, carrots, spinach, butternut squash, greens, broccoli, and cantaloupe Vitamin D - food sources are fatty fish and their oils and fortified foods Vitamin E - food sources include vegetable oils, nuts and seeds Vitamin K - food sources include vegetables, especially leafy and legumes 76. a 77. e 78. a 79. b 80. c 81. c 82. a 83. c 84. c 85. a 86. a 87. c 88. c 89. d 90. d

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Chapter 11: Major Minerals

Indicate the answer choice that best completes the statement or answers the question.

1. Major minerals include calcium, phosphorus, magnesium, sodium, potassium, and a. chloride b. manganese c. sulfur d. nitrogen e. niacin

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2. What is the most abundant divalent cation in the body? a. iron b. calcium c. selenium d. iodine e. zinc 3. Which mineral makes up about 40% of the body’s mineral mass? a. phosphorus b. magnesium c. calcium d. potassium e. manganese 4. Calcitriol can stimulate the absorption of calcium from the intestines by enhancing the synthesis of a. calsequestrin b. calcitonin c. calmodulin d. calbindin e. PTH 5. Which is true regarding paracellular absorption of calcium? a. occurs by diffusion mainly in the jejunum and ileum b. requires a membrane channel protein called TRPV6 c. requires energy and is saturable d. increases with low dietary calcium intakes e. occurs by diffusion mainly in the duodenum 6. Which substance can improve calcium absorption? a. lactose b. unabsorbed fatty acids c. phytic acid d. magnesium e. galactose

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Chapter 11: Major Minerals 7. What is secreted in response to low plasma calcium concentrations and acts on the kidney to increase the synthesis of calcitriol, which promotes renal reabsorption of calcium. a. calmodulin b. parathyroid hormone c. calcitonin d. calcitriol e. phytic acid 8. Which cells are considered the bone-building cells? a. osteonectins b. osteopontins c. osteoclasts d. osteoblasts e. calcitriol 9. During which period of the life cycle does peak bone mass occur? a. childhood b. puberty c. early adulthood d. middle age e. elderly 10. The binding protein that regulates many of the calcium-dependent enzymes is called: a. calcitonin b. calmodulin c. albumin d. globulin e. osteoblast 11. Which mineral, when combined with unabsorbed dietary fat, forms soaps that cannot be absorbed and are excreted in the feces? a. calcium b. sulphur c. potassium d. chloride e. magnesium 12. One health claim for calcium states that levels above a. 800 mg/day b. 1000 mg/day c. 1200 mg/day d. 2000 mg/day e. 500 mg/day

are unlikely to provide additional benefit.

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Chapter 11: Major Minerals 13. Major calcium loss from the body occurs via feces and urine. Which other process is associated with large losses of calcium? a. hyperventilation b. extreme sweating c. letting hair grow very long d. allowing nails to grow very long e. hypoventilation 14. In the renal system, which mineral regulates body fluid pH by reacting with secreted hydrogen ions, releasing sodium ions in the process? a. sulphur b. magnesium c. calcium d. phosphorus e. manganese 15. Which two minerals are the major part of the crystal, hydroxyapatite, formed in ossification of bone? a. sodium, chloride b. sulphur, magnesium c. calcium, phosphorus d. calcium, potassium e. potassium, magnesium 16. Which hormone both increases release of bone phosphorus into the blood and promotes urinary excretion of phosphorus? a. calcitonin b. calcitriol c. parathyroid hormone d. insulin e. estrogen 17. Phosphate balance is achieved largely by what process? a. renal excretion b. fecal excretion c. control of absorption by vitamin D d. control of absorption by phytates e. release of phytates into plasma 18. The majority of phosphorus that is not bound to protein is filtered by the glomerulus and is actively reabsorbed by the . a. distal tubule b. collecting duct c. loop of Henle d. proximal tubule

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Chapter 11: Major Minerals e. distal duct 19. Malnourished individuals exhibiting the “refeeding syndrome” may have low serum concentrations of which mineral? a. calcium b. sodium c. phosphorus d. chloride e. magnesium 20.

is the mineral for which deficiency is rarely seen. a. calcium b. phosphorus c. iodine d. zinc e. magnesium

21. Which mineral is part of the green chlorophyll pigment in green leafy vegetables? a. magnesium b. sodium c. potassium d. sulfur 22. Which mineral participates in all aspects of energy metabolism including glycolysis, beta-oxidation, and the TCA cycle? a. calcium b. iron c. magnesium d. sulphur e. phosphorus 23. Which mineral’s primary function is to bind phosphate groups in ATP and ATP-dependent enzyme reactions? a. calcium b. magnesium c. potassium d. sodium e. phosphorus 24. Which one of the following statements is not correct. a. About half of magnesium in the body is associated with the bones. b. Intracellular and serum magnesium levels are rigidly maintained. c. Magnesium in cells is associated with phospholipids and proteins. d. Magnesium metabolism is regulated by several hormones. e. A source of magnesium for some may be from medication.

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Chapter 11: Major Minerals 25. Which of the following statements is true? a. In smooth muscle contraction, the roles of calcium and magnesium are antagonistic, with calcium promoting the process and magnesium being the inhibitor if bound to sites that are normally occupied by calcium. b. Magnesium promotes phosphorus absorption. c. Calcium and magnesium promote each other’s reabsorption in the kidney. d. Calcium may cause an alteration in magnesium distribution by changing the flux of magnesium across the cell membrane or displacing it on its binding sites. e. Green leafy vegetables are not a good source of magnesium.

26. Deficiency of which major mineral is usually associated with muscular weakness, neuromuscular hyperexcitability, and tetany? a. magnesium b. calcium c. sulphur d. chloride e. phosphorus 27. About 99% of the body’s calcium is found where? a. blood plasma b. liver and kidneys c. bones and teeth d. extracellular fluid e. intracellular fluid 28. A calcium deficiency can lead to a. nyctalopia b. osteoporosis c. anemia

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d. xerophthalmia e. pellagra 29. Food sources of calcium include a. fresh fruit b. rice and oat milk c. radishes and cucumbers d. canned sardines e. tomato juice

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30. A deficiency of magnesium may lead to hypocalcemia due to what? a. a reduction in PTH levels b. inhibition of calcium absorption c. stimulation of calcium release from cells d. an increase in PTH levels

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Chapter 11: Major Minerals e. an increase in osteoclast production 31. Magnesium deficiency may develop due to mutations in what? a. PTH b. phytic acid c. claudin-16 d. FGF23 e. osteoblasts 32. Why are premature infants at risk for phosphorus deficiency? a. their poor absorption from the intestines b. their higher need for the mineral and the insufficient amount in human milk c. their highly active cytochrome P450 system d. their poorly developed intestines e. their lack of adipose tissue 33. Why does the Tolerable Upper Limit for phosphorus drop after age 70? a. slower metabolic rate in the elderly b. reduced need for phosphorus c. greater need for calcium d. greater likelihood of impaired renal function e. malabsorptive issues in intestines 34. One of the two mechanisms involved in calcium absorption in the small intestine is a. diffusion b. osmosis c. facilitated diffusion d. Brownian movement e. peristalsis 35. A factor that enhances calcium absorption is a. fat intake b. carbohydrate intake c. protein intake d. PUFA intake

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e. water intake 36. The active form of vitamin D in the body is a. calsequestrin b. calcitriol c. calcitonin d. calbindin e. D3

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Chapter 11: Major Minerals 37. Calcium is transported in the blood in all of the following ways except: a. bound to proteins b. complexed with anions c. ionized in the free form d. bound to hemoglobin e. bound to globulins 38. Ionized calcium is removed from the blood in all of the following ways except? a. secretion into the digestive tract b. excretion in the urine c. mixed into perspiration d. uptake by tissues e. with the help of CaSR to monitor blood calcium concentrations 39. Per serving, the best source of phosphorus would be which of the following? a. milk and yogurt b. dry roasted pecans c. an egg d. oat milk e. peanuts 40. How is most phosphorus, regardless of its dietary form, absorbed from the gastrointestinal tract? a. bound to proteins b. as free inorganic phosphate ions c. bound to carbohydrates d. bound to fats e. in chylomicrons 41. Where is phosphorus primarily absorbed? a. duodenum b. stomach c. ileum d. jejunum e. in bones 42. Most phosphorus is found in the blood in which form? a. HPO42b. H2PO4c. PO43d. H3PO42e. H2PO

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Chapter 11: Major Minerals 43. Uptake of phosphorus into cells is thought to occur via which channel? a. active transport b. facilitated diffusion c. passively, driven by the chemical gradient d. Brownian movement e. peristalsis 44. Resorption of phosphate from bone may take place through what? a. enhanced acid phosphatase activity b. enhanced alkaline phosphatase activity c. diminished acid phosphatase activity d. diminished alkaline phosphatase activity e. facilitated diffusion 45. What is a dietary mineral that is an important component of DNA and RNA? a. calcium b. magnesium c. sulfur d. phosphate e. iron 46. The presence of large amounts of unabsorbed fatty acids in the feces is referred to as a. steatorrhea b. amenorrhea c. constipation d. Crohn’s disease e. beriberi 47. Where are calcium-sensing receptors (CaSR) located? a. thyroid gland b. hypothalamus c. parathyroid glands d. liver e. stomach 48. Which of the following is NOT true regarding oxalic acid? a. is a salt-forming ion b. can reduce calcium absorption c. increases fecal calcium excretion d. is found in a variety of vegetables such as spinach and rhubarb e. is found in whole-grain bread and cereals

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Chapter 11: Major Minerals 49. What is the RDA for phosphorus for adults 19 and older? a. 1000 mg b. 700 mg c. 1200 mg d. 500 mg e. 400 mg 50. How many servings a day are recommended for dairy products? a. 1 b. 2 c. 3 d. 4 e. 5 51. Calcium-containing supplements are found in the marketplace in all the following forms except ? fill in the blank a. pill b. chewable c. powder d. liquid e. sublingual tablets 52. Which of the following foods has the greatest amount of calcium content per serving? a. walnuts b. pinto beans c. broccoli d. milk e. cottage cheese 53. Bone meal preparations (used as a calcium supplement) may contain this ingredient and should be avoided. a. nail shards b. oyster shells c. lead d. iron e. phosphorus 54. Which of the following is NOT true regarding calcium digestion? a. it takes about 1 hour at an acidic pH for calcium to be solubilized b. solubilization does not necessarily ensure better absorption c. calcium is present in foods as insoluble salts d. calcium is present in dietary supplements as insoluble salts e. fat must be present for digestion to occur

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Chapter 11: Major Minerals 55. What percentage of calcium absorption is seen in adults? a. 25-30% b. 20-25% c. 15-20% d. 10-15% e. 5%

56. What effect does taking a calcium supplement have on iron absorption, and what advice would you give to maximize the benefit from both minerals?

57. Explain the rationale for a common treatment of hyperphosphatemia associated with chronic kidney failure.

58. What role does magnesium play in maintaining calcium homeostasis?

59. Describe the mechanism for paracellular absorption of calcium.

60. Compare calcium, phosphorus, and magnesium as to their physiological functions, symptoms of a deficiency and some of their food sources. You may write out your response or set it up in table form.

61. Describe the process by which serum calcium concentrations increase in response to the removal of ionized calcium from the blood.

62. Explain how calcium status is assessed?

63. Explain the food sources of magnesium.

64. Discuss substrates/nutrients that affect intestinal magnesium absorption. You can make a table if you would like.

65. Discuss the studies and research regarding associations between alcohol intake and bone mineral density.

Indicate the answer choice that best completes the statement or answers the question.

66. Which of the following is true regarding magnesium absorption? a. protein inhibits absorption b. fiber enhances absorption c. phytic acid enhances absorption d. vitamin D enhances absorption e. vitamin D inhibits absorption 67. Where is most magnesium found in the body? a. intracellular fluid b. extracellular fluid c. white blood cells d. stomach

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Chapter 11: Major Minerals e. bone 68. Magnesium interacts with this nutrient and inhibits its absorption. a. phosphorus b. calcium c. iron d. niacin e. vitamin C 69. How much filtered magnesium is reabsorbed as it goes through the kidneys? a. 50-55% b. 70-75% c. 90-94% d. 95-97% e. 100% 70. Which of these is true for the RDA of magnesium? a. lactating women should avoid magnesium b. females need 3000 mg per day c. pregnant women should avoid magnesium in their diets d. males 18-30 years of age need 400 mg per day e. all adults need 500 mg per day

Indicate whether the statement is true or false.

71. Calcium is the most abundant divalent cation in the body. a. True b. False 72. Meats and grains are poor sources of calcium. a. True b. False 73. Calcium absorption occurs in the large intestine. a. True b. False 74. Thyroid hormone increases serum calcium concentrations. a. True b. False 75. Phosphorous is second to calcium in abundance in the body. a. True b. False

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Chapter 11: Major Minerals 76. Phosphorous absorption takes place in the small intestine, predominantly in the jejunum. a. True b. False 77. Aluminum and magnesium hydroxides and calcium carbonates and acetates are used today for the treatment of hyperphosphatemia in individuals with renal failure. a. True b. False 78. Calcitriol enhances calcium reabsorption in the kidneys. a. True b. False 79. A chronic phosphorous deficiency in children will cause the development of osteomalacia. a. True b. False 80. Absorption of magnesium decreases as intracellular magnesium concentrations increase. a. True b. False 81. Vitamin D, fructose, and oligosaccharides may decrease magnesium absorption. a. True b. False 82. The ingestion of protein-rich foods has been suggested to negatively affect bone health due to the production of a higher acid load. a. True b. False 83. It is suggested that calcium supplementation alone, without vitamin D for fracture risk reduction, is not efficient. a. True b. False 84. Osteoporosis is diagnosed with a T score less than 25 standard deviations above the bone mineral density of young adults. a. True b. False 85. One in every two women over the age of 50 years in the US will suffer a fracture sometime in their life due to osteoporosis. a. True b. False

Indicate the answer choice that best completes the statement or answers the question.

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Chapter 11: Major Minerals 86. Dowager’s hump is also known as what? a. pellagra b. beriberi c. nyctalopia d. kyphosis e. osteoblasts 87. A deficiency of magnesium can be assessed with a twenty-four-hour urinary magnesium of less than what? a. 80 mg b. 200 mg c. 100 mg d. 150 mg e. 117 mg 88. Which of these is NOT true regarding magnesium toxicity? a. can cause nausea and vomiting b. can cause dehydration c. can cause diminished loss of deep tendon reflexes d. is called beriberi e. can only be caused by overconsuming food sources of magnesium 89. Which of the following is NOT true regarding caffeine and calcium? a. caffeine affects calcium balance b. caffeine reduces the renal reabsorption of calcium c. caffeine increases osteoclast production d. caffeine has been positively associated with fracture risk in women in some studies e. caffeine may increase urinary calcium losses 90. Which of these is NOT true about food sources of magnesium? a. “hard” tap water may contain dietary magnesium b. food processing such as refining whole wheat reduces the magnesium content c. the best sources are nuts, seeds, and whole-grain cereal d. the best sources are milk and dairy e. the chlorophyll in dark green leafy vegetables contains magnesium

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Chapter 11: Major Minerals Answer Key 1. a 2. b 3. c 4. d 5. a 6. a 7. b 8. d 9. c 10. b 11. a 12. d 13. b 14. d 15. c 16. c 17. a 18. d 19. c 20. b 21. a 22. c 23. b 24. d 25. a

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Chapter 11: Major Minerals 26. a 27. c 28. b 29. d 30. a 31. c 32. b 33. d 34. a 35. c 36. b 37. d 38. c 39. a 40. b 41. d 42. a 43. c 44. b 45. d 46. a 47. c 48. e 49. b 50. c 51. e

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Chapter 11: Major Minerals 52. d 53. c 54. e 55. a 56. Grading rubric – answer should include the following items: Calcium supplements inhibit the absorption of iron, especially nonheme iron, likely by causing the ferroportin protein to disengage from the basolateral membrane, diminishing iron absorption. Because this lower iron absorption has been shown to be temporary, an adaptation likely occurs that does not affect the iron status of the body.

57. Grading rubric – answer should include the following items: Kidney failure results in greatly elevated concentrations of phosphate in blood. Calcium supplements given so that the ratio of calcium to phosphorus is 3:1 or greater effectively inhibit the absorption of phosphate from the intestines. This treatment is now less common because of the risk of hypercalciuria, calcium-alkali syndrome, and calcium phosphate deposition in soft tissues.

58. Grading rubric – answer should include the following items: Magnesium (Mg) is a divalent cation that sometimes mimics calcium (Ca) and sometimes competes with Ca. Mg competes with Ca for reabsorption by the kidney. Mg can decrease calcium flux across cell membranes. It can inhibit Ca release from the sarcoplasmic reticulum and activate the Ca-ATPase pump to decrease intracellular Ca. In addition, Mg competes with Ca to bind sites on smooth muscle, thus inhibiting contraction, which is likely one mechanism by which adequate Mg decreases risk for hypertension.

59. Paracellular absorption of calcium occurs by diffusion where no carriers or energy are needed. It occurs throughout the small intestine, predominantly in the jejunum and ileum and is concentration dependent. This kind of absorption occurs between cells and is affected by tight junctions that are controlled by occludins and claudins and appear to exhibit properties similar to ion channels. This type of absorption occurs when high calcium concentrations are present in the lumen, creating a gradient of calcium concentrations between the lumen and the basolateral side of the enterocyte. Permeability is increased through the junctions by a series of reactions and calcium absorption is facilitated.

60. The students will use the information in Table 11.1 to answer this question, leaving out the columns for body content and RDA. 61. Grading rubric – answer should include the following items: Calcium-sensing receptors on the parathyroid glands and some other tissues monitor blood calcium concentrations.

When a drop in serum calcium concentration occurs, the parathyroid gland releases PTH into the blood. This will increase serum calcium concentrations via actions in the kidneys and the bones.

In the kidneys, the hormone stimulates transcription of 1-hydroxylase yielding synthesis of calcitriol from 25-OH vitamin D. This leads to increased renal absorption of filtered calcium by interacting with nuclear vitamin D receptors to induce transcription of the gene that codes for calbindin D28k.

In the bones, PTH attaches to receptors on osteoblasts. These cells can differentiate into osteoclasts that degrade bone.

They promote the release of calcium from the bones into the blood, which brings about an increase in serum calcium levels.

The calcitriol that was produced acts in the small intestine to increase calcium absorption by interacting with nuclear vitamin D receptors to induce transcription of the gene that codes for calbindin D9k. This substance binds protein to

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Chapter 11: Major Minerals allow for transport of calcium through the cytosol. In addition, calcitriol enhances calcium absorption at the brush border of the enterocytes by increasing TRPV6 channels and, at the basolateral membrane, by increasing calcium ATP-ase pumps.

62. Grading rubric – answer should include the following items: Because of the precise regulation of serum calcium, there is no routine biochemical method of serum calcium status. In certain disease states, abnormal serum calcium levels develop. This is particularly true in cases of cancer and renal failure. Also, changes in blood pH and albumin may bring about changes in serum calcium concentrations. So, checking serum albumin levels is important. If serum albumin is normal, the ratio between bound calcium and ionized calcium remains constant. If albumin levels drop, protein-bound calcium will also drop and treatment is needed to correct the situation. Another means of assessment is measuring bone mineral density since most calcium is found in the bones.

This is done using dual-energy X-ray absorptiometry (DEXA or DXA), computerized tomography (CT), and single-photon absorptiometry.

63. Grading rubric – answer should include the following items: Magnesium is found in a wide variety of foods including nuts, seeds, and whole-grain cereals. Food processing such as refining whole wheat, substantially reduces its magnesium content. Green leafy vegetables also provide significant amounts of magnesium, although it is the chlorophyll that contains magnesium. Legumes, lentils, spices, seafood, and dairy products also contribute to dietary magnesium as does hard tap water.

64. Refer to Table 11.9 that lists substances and nutrients that both enhance or inhibit absorption.

65. Grading rubric – answer should include the following items: Most of the studies examining this topic date back to the 1990s and early 2000s. Findings linking consumption of alcohol in moderation with bone mineral content are conflicting. However, higher alcohol intakes among postmenopausal women have been more strongly associated with lower bone mineral density and increased fracture risk. It is wise to suggest that if alcohol is consumed, limiting consumption would be beneficial for bone health.

66. d 67. e 68. a 69. d 70. d 71. True 72. True 73. False 74. False 75. True 76. True

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Chapter 11: Major Minerals 77. False 78. False 79. False 80. True 81. False 82. True 83. True 84. False 85. True 86. d 87. a 88. d 89. c 90. d

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Chapter 12: Water and Electrolytes

Indicate the answer choice that best completes the statement or answers the question.

1. Which process gives the body the capacity to maintain constancy in the internal environment? a. osmotic pressure b. osmolality c. homeostasis d. acid-base balance e. sodium-potassium pump 2. Water accounts for what percentage of the body weight in a normal adult? a. 20% b. 40% c. 60% d. 80% e. 90% 3. Which body water reservoir is made up of plasma and interstitial fluid? a. intracellular b. extracellular c. total body water d. glomerular filtrate e. plasma 4. Colloid osmotic pressure attracts water into the plasma and is mainly due to what? a. large protein molecules b. the pumping of the heart c. sodium ions d. chloride ions e. potassium ions 5. What is the major filtration force in the capillaries that is responsible for controlling movement of water from plasma to interstitial fluid and from interstitial fluid into plasma? a. colloid osmotic pressure b. theoretic osmotic pressure c. hydrostatic pressure d. effective osmotic pressure e. sodium potassium pump 6. Bone contains what percentage of water? a. 25% b. 31% c. 43% d. 51% e. 75%

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Chapter 12: Water and Electrolytes 7. Which of the components comprising the nephron includes the capillary network called the glomerulus? a. collecting duct b. distal convoluted tubule c. loop of Henle d. Bowman’s capsule e. lower esophageal sphincter 8. Which organs are responsible for regulation of extracellular water osmolarity and volume? a. hypothalamus and kidney b. liver and pancreas c. pancreas and kidney d. spleen and bone marrow e. large intestine 9. What percentage of the glomerular filtrate volume is excreted as urine each day? a. 100% b. 50% c. 25% d. 1% e. 10% 10. Which hormone, mediated by the enzyme renin, is primarily responsible for active reabsorption of sodium ions in the distal and collecting tubules? a. antidiuretic hormone b. aldosterone c. androsterone d. adrenocortical e. insulin 11. Which hormone, stimulated by increased blood pressure stretching the heart, functions to inhibit sodium reabsorption to promote sodium excretion? a. vasopressin b. atrial natriuretic peptide c. aldosterone d. angiotensin II e. insulin 12. Which of the following is NOT a cationic electrolyte of extracellular fluid? a. sodium b. potassium c. calcium d. bicarbonate e. chloride

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Chapter 12: Water and Electrolytes 13. Which hormone hydrolyzes angiotensinogen, thus generating angiotensin I? a. renin b. aldosterone c. angiotensin-converting enzyme d. atrial natriuretic peptide e. vasopressin 14. Dietary intake of which mineral correlates positively with blood pressure? a. magnesium b. calcium c. potassium d. sodium e. iron 15. Which of the following is the most abundant cation in blood plasma? a. potassium b. magnesium c. manganese d. sodium e. calcium 16. A good predictor of hypertension is a measurement of which of the following? a. serum sodium concentration b. urinary sodium excretion c. average daily sodium intake d. sodium filtration rate by the kidney e. GFR 17. A food may be labeled “low sodium” if each serving provides less than what? a. 5 mg b. 35 mg c. 140 mg d. 240 mg e. 300 mg 18. Significant loss of what mineral occurs when one exercises vigorously while the temperature is high? a. sulfur b. phosphorus c. sodium d. potassium e. calcium 19. Which mineral serves as the major intracellular fluid cation?

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Chapter 12: Water and Electrolytes a. calcium b. chloride c. sodium d. potassium e. magnesium 20. Which is the chief cation of intracellular fluid for which maintenance of normal levels is essential to life of the cells? a. calcium b. sodium c. potassium d. bicarbonate e. magnesium 21. What condition may result in cardiac arrhythmias when extracellular potassium is increased? a. hypernatremia b. hypokalemia c. hyperkalemia d. hyponatremia e. osteoporosis 22. Which mineral is the most abundant anion found in extracellular fluid? a. sodium b. chloride c. phosphorus d. magnesium e. calcium 23. What is a major function of chloride? a. protein synthesis in cells b. the principal intracellular electrolyte c. wound healing d. maintenance of gastric acidity e. provides ATP to cells 24. Acid-base balance refers to what? a. the ratio of acidic and basic foods consumed each day b. the concentration of the bicarbonate ion in the red blood cells c. the control of the hydrogen ion concentration in body fluids d. homeostasis e. the minimum level of pH needed for cells to function 25. Which of the following is NOT true regarding aldosterone? a. inhibits reabsorption of sodium

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Chapter 12: Water and Electrolytes b. simulated by decreased plasma sodium concentration c. stimulated by increased plasma potassium d. simulated by decreased concentrations of natriuretic peptides e. stimulated by angiotensin 26. When does acidosis occur? a. the plasma concentration of H ions falls below the normal range b. the plasma concentration of H ions exceeds the normal range c. chloride ion concentration exceeds hydrogen ion concentration d. sodium ion concentration exceeds chloride ion concentration e. the chloride ion concentration equals hydrogen ion concentration 27. Which of the physiological buffers is able to neutralize both acids and bases? a. bicarbonate-carbonic acid system b. hydrochloric acid system c. phosphates d. proteins e. lipids 28. Of these blood proteins, which one contributes most to buffering? a. albumin b. gamma globulins c. hemoglobin d. transthyretin e. bicarbonate 29. Which enzyme facilitates formation of carbonic acid? a. renin b. angiotensinogen c. angiotensin d. carbonic anhydrase e. PTH 30. When hyperventilation occurs, there is a(n) . a. increased loss of CO2 and a decreased production of carbonic acid b. decreased loss of CO2 and an increased production of carbonic acid c. decrease in both CO2 and carbonic acid levels d. increase in both CO2 and carbonic acid levels e. equilibrium that occurs in the lungs 31. When a person hyperventilates and “blows off” CO2, what effect does this have on pH? a. lowers it

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Chapter 12: Water and Electrolytes b. raises it c. does not alter it significantly d. delays any changes in it e. does not alter it at first but will lower it later on 32. What is the condition that occurs in starvation or diabetes in which there is an increase in the urinary excretion of ammonia? a. metabolic alkalosis b. metabolic acidosis c. respiratory alkalosis d. respiratory acidosis e. anabolic shock 33. Which buffer is controlled by the kidneys? a. bicarbonate b. carbonic acid c. protein d. ammonium e. chloride 34. Which characteristic of water gives it the ability to regulate body temperature? a. high solubility coefficient b. hydrogen bonding between molecules c. high specific heat d. polar covalent bonding of the water molecules e. thermogenesis 35. Maintenance of blood volume is directly related to control of which of the following? a. appetite b. thyroid hormone level c. respiratory rate d. blood pressure e. gluconeogenesis 36. The reaction H2O + CO2 ↔ H2CO3 ↔ HCO3- + H+ represents water’s role in what? a. protein transport b. ammonium ion excretion c. acid-base balance d. temperature regulation e. lipid transport chain 37. Which of the following is correct regarding interstitial fluid? a. directly bathes the cells

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Chapter 12: Water and Electrolytes b. is the fluid portion of the blood c. is fluid that is redirected to the blood plasma from interstitial spaces d. is a water-containing and sometimes viscous fluid e. is responsible for bone mineralization loss 38. Which fluid makes up the highest percentage of body weight? a. intracellular water b. total body water c. extracellular water d. interstitial fluid e. interstitial bone marrow 39. Sodium, potassium, calcium, and magnesium are considered what? a. organic acids b. inorganic acids c. buffers d. cationic electrolytes e. inorganic salts 40. Water is lost from the body each day primarily through what? a. feces b. sweat c. urine d. evaporation from respiration e. tear ducts 41. What is the major source of water for the body? a. beverages and foods b. water as a byproduct of metabolism c. inhaled water vapor from the atmosphere d. subcutaneous fluid absorption e. hydrolysis reactions 42. The movement of water among the various body compartments is regulated by the presence of what? a. potassium in the extracellular fluid compartment b. sodium in the extracellular fluid compartment c. potassium in the intracellular fluid compartment d. chloride in the intracellular fluid compartment e. chloride in the extracellular fluid compartment 43. Not including physically active adults, the recommended fluid intake for the average adult is approximately how many mL of water per kg of body weight.

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Chapter 12: Water and Electrolytes a. 15-35 mL b. 20-50 mL c. 25-40 mL d. 40-60 mL e. 60-80 mL 44. Approximately how much water is released into the gastrointestinal tract daily as part of secretions? a. 9 L b. 7 L c. 4 L d. 3 L e. 1 L 45. Which of these cations is most abundant in plasma? a. magnesium b. calcium c. sodium d. potassium e. chloride 46. Where is the majority of water in the gastrointestinal tract absorbed? a. duodenum b. jejunum and ileum c. ascending colon d. transverse colon e. rectum 47. What is hyperkalemia normally associated with? a. renal failure b. too much potassium in the diet c. type 2 diabetes d. Crohn’s disease e. obesity 48. The anions in extracellular fluid (ECF) are chloride and what? a. magnesium b. ammonium c. phosphate d. bicarbonate e. phosphorus 49. What is the major route of chloride excretion? a. feces

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Chapter 12: Water and Electrolytes b. kidneys c. sweat d. respiration e. skin 50. How is chloride status accessed? a. sweat test b. 24-hour urine status c. concentration in the serum d. feces excretion test e. There are currently no ways to assess chloride status.

Indicate whether the statement is true or false.

51. Electrolytes in the fluid compartments are distributed in such a way that within the compartment, electrical neutrality is always maintained. a. True b. False 52. Urinary loss of water averages approximately 1-2 L/day. a. True b. False 53. Water moves among the various body compartments in a regulated manner strongly affected by sodium in the intracellular fluid compartment. a. True b. False 54. Diffusion refers to the movement of water across a semipermeable membrane based on differences in solute concentrations. a. True b. False 55. Factors that determine the Adequate Intake (AI) of water include age, gender, environment, level of physical activity, and rate of metabolism. a. True b. False 56. Hydrostatic pressure affects water movement between the interstitial fluid and the plasma. a. True b. False 57. The concentration of proteins is much higher in the plasma than in the interstitial fluid because proteins are too large to pass through the capillary endothelium. a. True

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Chapter 12: Water and Electrolytes b. False 58. Stimulation of reabsorption of water in the kidneys is mediated by angiotensin I. a. True b. False 59. In the kidneys, 80% of plasma that does not enter the glomerulus flows through the afferent arterioles. a. True b. False 60. The bicarbonate-carbonic acid system is the major regulatory factor controlling sodium and chloride balance in the body. a. True b. False 61. The majority of sodium absorption occurs in the small intestine and the proximal portion of the colon. a. True b. False 62. No Tolerable Upper Intake Level has been established for potassium from food. a. True b. False 63. Chloride is almost completely absorbed in the intestines. a. True b. False 64. Some manifestations of hypokalemia include muscle weakness, lethargy, and cardiac arrhythmias. a. True b. False 65. Hydrostatic pressure affects water movement within the two main ECF compartments. a. True b. False

66. Discuss the sequence of events of the maintenance of fluid homeostasis by the renin-angiotensin-aldosterone system.

67. Explain how ACE inhibitors work to treat hypertension.

68. What are the recommended Adequate Intake (AI) values of water for adults? What factors will cause modifications in these values?

69. Explain the relationship between dietary sodium intake and essential hypertension.

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Chapter 12: Water and Electrolytes 70. Describe three mechanisms by which the kidneys conserve/excrete potassium or maintain potassium balance.

71. What is the basis for replacing some of the NaCl in the diet with KCl, and how does it work?

72. Describe what (if any) issues a chloride deficiency might lead to problems in. Give details.

73. What is a potassium deficiency called? Describe situations in which potassium deficiencies can occur.

74. Describe the terminology used on food labels that indicates specific amounts of sodium per serving.

75. Briefly describe the renin-angiotensin-aldosterone system and sodium balance.

Indicate the answer choice that best completes the statement or answers the question.

76. Which term refers to the movement of water across a semipermeable membrane? a. equilibrium b. active transport c. facilitated diffusion d. osmosis e. passive diffusion 77. What are the best sources for dietary potassium? a. lean protein b. dairy c. condiments d. fruits and vegetables e. coffee 78. What is the Daily Value for sodium used on food labels in the US? a. 1500 mg b. 2000 mg c. 2300 mg d. 2800 mg e. 3200 mg 79. Which of the following foods would have the lowest amount of sodium per serving? a. cheese b. sauerkraut c. ketchup d. taco seasoning e. apple slices 80. What is the AI for sodium for a typical adult? a. 500 mg

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Chapter 12: Water and Electrolytes b. 1000 mg c. 1500 mg d. 2000 mg e. 2500 mg 81. What is the typical range of blood osmolarity? a. 280-295 mOsm/L b. 300-310 mOsm/L c. 200-210 mOsm/L d. 350-400 mOsm/L e. 190-210 mOsm/L 82. Which of these can be thought of as the solute (particle) concentration of a fluid? a. active diffusion b. hydrostatic pressure c. dilution d. osmolarity e. solute load 83. Physically active adults may need an excess of how many L of water (fluid) per day? a. 4 L b. 3 L c. 2 L d. 1 L e. 0.5 L 84. If using the energy intake equation to calculate water needs, how many mL per kcal would a person need? a. 0.5 mL b. 1 mL c. 1.5 mL d. 2 mL e. 2.5 mL 85. Which of these do NOT affect your water intake needs? a. age b. gender c. bone mass d. environment e. rate of metabolism 86. How are recommendations for water published? a. RDA

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Chapter 12: Water and Electrolytes b. AI c. TUL d. EER e. there are no recommendations for water 87. Which of the following is the most significant contribution to variations of body water? a. kidney function b. muscle mass c. fat mass d. age e. height 88. How much of one’s body weight is typically made up of water? a. 10-15% b. 20-25% c. 25-35% d. 40-80% e. ~85% 89. Which of the following would you eat if you were consuming the DASH diet? a. low-fat, rich in fruits and vegetables, and low-fat dairy b. average fat, low in fruits and vegetables c. low fat, low in fruits and vegetables d. low fat, average fruits and vegetables e. high fat, low carbohydrate 90. Where does the phosphate buffer system mainly operate? a. extracellular fluid b. serum plasma c. within cells d. bone matrix e. hemoglobin

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Chapter 12: Water and Electrolytes Answer Key 1. c 2. c 3. b 4. a 5. c 6. a 7. d 8. a 9. d 10. b 11. b 12. d 13. a 14. d 15. d 16. c 17. c 18. c 19. d 20. c 21. c 22. b 23. d 24. c 25. a

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Chapter 12: Water and Electrolytes 26. b 27. d 28. c 29. d 30. a 31. b 32. b 33. a 34. c 35. d 36. c 37. a 38. b 39. d 40. c 41. a 42. b 43. c 44. b 45. c 46. b 47. a 48. d 49. b 50. c 51. True

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Chapter 12: Water and Electrolytes 52. True 53. False 54. False 55. True 56. True 57. True 58. False 59. False 60. False 61. True 62. True 63. True 64. True 65. True 66. Grading rubric – answer should include the following items: The renin-angiotensin-aldosterone system controls thirst and both sodium and water excretion to maintain fluid balance. When dehydration occurs and plasma volume falls or blood pressure falls in the glomerulus, active renin is secreted by the kidneys. Renin is an enzyme that converts angiotensinogen (made in the liver) in the bloodstream to angiotensin I. As angiotensin I passes through the lungs, angiotensin-converting enzyme changes it to angiotensin II. Angiotensin II has three important actions to restore blood volume. It acts on the hypothalamus to stimulate thirst and acts on the hypothalamus to stimulate production of vasopressin, which in turn acts on the kidney to retain water.

Angiotensin II also acts on the adrenal cortex to stimulate production of aldosterone, which in turn acts on the kidney to increase reabsorption of sodium in the kidney tubules. Increased thirst and drinking behavior, plus increased retention of water and sodium by the kidney, serve to normalize fluid balance.

67. Grading rubric – answer should include the following items: Angiotensin II is created from angiotensin I in the lungs by the action of angiotensin converting enzyme (ACE).

Angiotensin II has several roles in raising blood pressure including causing an increase in thirst, an increase in secretion of vasopressin leading to water retention and an increase in secretion of aldosterone from the adrenal cortex that leads to sodium retention and water retention. All of these will raise blood pressure. By inhibiting ACE, none of these effects will occur and blood pressure will become lower.

68. Grading rubric – answer should include the following items: The AI recommendation for adult females is 2.7 L and for adult males is 3.7 L, which allows for intake from foods and beverages consumed daily. These amounts will vary based on age, gender, environment, level of physical activity, rate

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Chapter 12: Water and Electrolytes of metabolism, level of energy intake, and body weight.

69. Grading rubric – answer should include the following items: Accumulation of sodium in body water is followed by retention of water and therefore expansion of blood volume, which increases intravascular pressure, resulting in hypertension. For those who do not excrete sodium normally, high dietary intake of sodium, which is almost completely absorbed, will result in essential hypertension.

70. Grading rubric – answer should include the following items: Extracellular potassium, especially the blood level, is tightly regulated because it can be lethal if the concentration is too high or too low. If blood potassium is too high, aldosterone is released to enhance the excretion of potassium and also causes more potassium to be secreted into the glomerular filtrate. Similarly, vasopressin can enhance excretion. If blood potassium is too low, less aldosterone is stimulated and more potassium is retained by the kidneys. A third mechanism that is less well understood can control potassium levels and acts especially after a high-potassium meal to prevent hyperkalemia. It involves the actions of insulin, glucagon, and a kidney protein that quickly removes potassium from the blood to prevent blood concentrations from becoming too high.

71. Grading rubric – answer should include the following items: The basis for replacing NaCl with KCl is that potassium has been associated with lower calcium urinary excretion, whereas sodium increases it. Studies where KCl replaces some NaCl, as well as studies with supplemental potassium citrate demonstrate reduced urinary calcium with the increased potassium.

72. Grading rubric – answer should include the following items: Because chloride has several functions in the body, different systems will be affected by a deficiency. Since chloride is a basic component of the hydrochloric acid in the stomach, a deficiency will lead to a decrease in the production of HCl, thus affecting digestion. In the immune system, chloride is released by white blood cells during phagocytosis to assist in destruction of foreign substances. A deficiency will interfere with the phagocytic process and will reduce the efficiency of the immune system. Because chloride acts as the exchange anion for bicarbonate in red blood cells allowing for transport of tissue-derived CO2 back to the lungs, a respiratory acidosis might develop as less CO2 is expelled due to reduced transport.

73. Grading rubric – answer should include the following items: Potassium deficiency is known as hypokalemia. While dietary intake of potassium by many Americans is lower than the AI, hypokalemia most often results in situations such as excessive vomiting or diarrhea. Additionally, a magnesium deficiency that promotes potassium excretion and the use of some medications used to treat high blood pressure may increase urinary potassium excretion thus causing a deficiency.

74. Grading rubric – answer should include the following items: Free- less than 5 mg of sodium per serving Very low- less than 35 mg per serving Low- less than 140 mg per serving Reduced/less- at least 25% less sodium per serving than that of the appropriate referenced food Light- may be used if the food is low in calories and fat and the sodium content has been reduced by at least 50% 75. Grading rubric – answer should include the following items: The major regulatory factor controlling sodium (and chloride) balance is the body’s renin-angiotensin-aldosterone system (RASS). This system enhances sodium and chloride reabsorption with water (fluid) balance also affected since water reabsorption follows the reabsorption of the electrolytes. The RASS is active when ECF volume and blood pressure are low and is initiated by the action of renin.

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Chapter 12: Water and Electrolytes 76. d 77. d 78. c 79. e 80. c 81. a 82. d 83. b 84. b 85. c 86. b 87. c 88. d 89. a 90. c

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Chapter 13: Essential Trace and Ultratrace Minerals

Indicate the answer choice that best completes the statement or answers the question.

1. Which of the microminerals is considered essential for normal brain function? a. chromium b. fluorine c. vanadium d. manganese e. copper 2. What is the average iron content in the American diet? a. 1–4 mg iron per 1,000 kcal b. 5–7 mg iron per 1,000 kcal c. 8–15 mg/day d. 18 g /day e. 20-25 mg/day 3. Which of the following dietary substances inhibits uptake of nonheme iron? a. ascorbic acid b. lactic acid c. tea d. MFP e. cellulose 4. Absorption of dietary iron is regulated by this substance that is produced by the liver when iron stores are high and released to the blood to act at the surface of enterocytes and macrophages. a. hepcidin b. hephaestin c. ferroportin d. hemoglobin e. hemopoietin 5. Which mineral is critical for oxidizing iron to be bound by transferrin for delivery to the tissues from the gut and liver? a. zinc b. manganese c. copper d. chromium e. iodine 6. Where would you find iron regulatory proteins (IRPs)? a. cytosol b. nucleus c. mitochondria d. Golgi apparatus

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Chapter 13: Essential Trace and Ultratrace Minerals e. nucleic acid 7. In the presence of low intracellular iron, the binding of iron regulatory protein (IRP) to iron response elements (IREs) present on the ferritin mRNA . a. results in a decrease in ferritin abundance b. results in an increase in ferritin abundance c. occurs only when intracellular iron concentrations are high d. does not occur e. results in an equilibrium of ferritin 8. The binding of iron by proteins defends the cells against what? a. iron deposition in kidneys and other organs b. oxidative damage from free radicals c. tissue hypoxia d. stellate cells e. excessive heme accumulation 9. Which statement is false? a. Hemosiderin as a storehouse of iron predominates when iron concentrations in the liver are low. b. Iron is stored mainly in the liver, bone marrow, and spleen. c. Iron is released more slowly from hemosiderin than from ferritin. d. Ferritin is an unstable compound that is constantly being degraded and resynthesized. e. Iron is found in foods in two forms: heme and nonheme.

10. Which vitamins/minerals are required for heme synthesis? a. vitamin E, vitamin C, and iron b. folate, B12, and iron c. B6, zinc, and iron d. copper, zinc, and folate e. manganese and iodine 11. Which mineral facilitates transfer of electrons in the electron transport chain? a. calcium b. nickel c. zinc d. iron e. copper 12. Excessive intake of nonheme iron interferes with absorption of which mineral by an unknown mechanism? a. manganese b. zinc c. chromium d. selenium

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Chapter 13: Essential Trace and Ultratrace Minerals e. copper 13. Hemoglobin and hematocrit are common measurements for assessment of nutriture for which mineral? a. iodine b. zinc c. chromium d. iron e. copper 14. Which of the following is true regarding ZIP4? a. mutations result in zinc toxicity due to acrodermatitis enteropathica b. is the primary transporter of zinc into enterocytes c. is expressed only in the liver d. degrades more rapidly when zinc intakes are low e. is not needed for zinc absorption 15. Which trace mineral participates in the greatest number of enzyme systems? a. zinc b. iron c. selenium d. copper e. molybdenum 16. The enzyme that converts retinol to retinal and ethanol to acetylaldehyde contains four a. copper b. iodine c. zinc d. iron e. manganese 17. Zinc is important for taste perception as a component of a. carbonic anhydrase b. alcohol dehydrogenase c. gustin d. metallothionein e. ZIP4

atoms.

.

18. At the cellular level, which mineral interacts with vitamin A by promoting growth and helping to synthesize retinolbinding protein? a. cobalt b. zinc c. silicon d. chromium

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Chapter 13: Essential Trace and Ultratrace Minerals e. iodine 19. Which amino acid may enhance copper absorption? a. alanine b. serine c. cysteine d. lysine e. arginine 20. Which of the following dietary components impedes copper absorption? a. gluconate b. phosphate c. citric acid d. phytic acid e. phosphorus 21. What protein plays a dual function in both iron and copper homeostasis? a. ferritin b. transferrin c. metallothionein d. ceruloplasmin e. cysteine 22. Zinc is found in foods complexed with amino acids in which family? a. eicosanoids b. steroids c. peptides and proteins d. amines e. glutamine 23. Which two minerals are readily oxidized within tissues? a. iron and copper b. zinc and molybdenum c. iodine and manganese d. zinc and copper e. iodine and zinc 24. What genetic disorder causes copper toxicity? a. hemochromatosis b. Keshan disease c. Menkes disease d. Wilson’s disease e. Crohn’s disease

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Chapter 13: Essential Trace and Ultratrace Minerals 25. Which statement about selenium metabolism is true? a. Free selenide can be converted into selenophosphate. b. Selenocysteine is degraded to yield selenomethionine. c. Dietary selenocysteine can be utilized directly to produce selenium-dependent enzymes. d. Significant cellular damage occurs only with complete cessation of selenoprotein synthesis. e. Binds and promotes zinc absorption.

26. Which mineral is an essential factor in the action of glutathione peroxidase (GPX) in the reduction of organic peroxides and hydrogen peroxide? vanadium a. molybdenum b. selenium c. silicon d. vanadium e. copper 27. When superoxide radicals accumulate, superoxide dismutase catalyzes the formation of hydrogen peroxide. What happens to the hydrogen peroxide? a. It freely dissociates to water. b. It is excreted in the urine and through the lungs. c. It is converted to water and oxygen via catalase or glutathione peroxidase. d. It is used in the synthesis of DNA and RNA. e. It is converted to H+.

28. Peroxynitrite is synthesized by activated white blood cells from which radicals? a. superoxide b. glutathione c. nitrogen monoxide d. iodothyronine e. metallothionein 29. Selenium deficiency is linked to which disease? a. Menkes b. Keshan c. Kashin-Beck d. a and b e. b and c 30. Which micromineral is necessary for iodine metabolism? a. fluorine b. manganese c. chromium d. selenium

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Chapter 13: Essential Trace and Ultratrace Minerals e. copper 31. Which nonmetal nutrient deficiency is associated with Keshan disease, characterized by cardiomyopathy? a. iodine b. zinc c. selenium d. molybdenum e. calcium 32. What is chromium absorption is inhibited by? a. antacids b. methionine c. picolinic acid d. phenylalanine e. histidine 33. Which mineral is thought to potentiate the action of insulin? a. chromium b. manganese c. copper d. cobalt e. zinc 34. The primary physiological role of which mineral is to act as a constituent in the thyroid hormones? a. fluorine b. iodine c. selenium d. chromium e. molybdenum 35. The addition of which food to the diet will alleviate the problem of endemic goiter? a. cabbage b. broccoli c. cassava d. iodized salt e. tomato juice 36. Iodine deficiency associated with neurological problems in infants results in a. cretinism b. Keshan disease c. goitrin d. goiter e. Wilson’s disease

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Chapter 13: Essential Trace and Ultratrace Minerals 37. Arginase, a key enzyme in liver urea production, requires four a. iron b. copper c. zinc d. manganese e. selenium

atoms per molecule.

38. Which trace mineral is important for activating a key enzyme in gluconeogenesis? a. iron b. copper c. iodine d. manganese e. selenium 39. Which mineral serves as a cofactor in xanthine oxidase in the metabolism of purines, pyrimidines, and pteridines? a. manganese b. molybdenum c. copper d. chromium e. selenium 40. People living in regions that contain high soil molybdenum levels may develop what condition? a. gout b. heart disease c. reduced urea production d. cretinism e. goiter 41. Where is heme readily absorbed? a. colon b. distal jejunum and ileum c. duodenum and proximal jejunum d. stomach e. duodenum 42. Lithium carbonate is one of the medications used to treat bipolar disorder. What condition might develop in patients using this medication? a. iron-deficiency anemia b. glucose intolerance c. Keshan disease d. hypothyroidism e. hyperkalemia

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Chapter 13: Essential Trace and Ultratrace Minerals 43. The chemistry of selenium is similar to what? a. phosphorus b. sulfur c. chloride d. bromine e. potassium 44. Hypochromic, microcytic anemia is associated with a deficiency of which mineral? a. selenium b. iron c. copper d. molybdenum e. phosphorus 45. In addition to an actual deficiency of iron, iron-deficiency anemia may develop when normal iron levels are present but there is a deficiency of which other mineral? a. copper b. zinc c. selenium d. iodine e. cobalamin 46. Iron-deficiency anemia related to copper deficiency occurs due to the reduced activity of what? a. cytochrome c oxidase b. lysyl oxidase c. pteridines d. ceruloplasmin e. ferritin 47. Where is selenium absorbed? a. small intestine b. large intestine c. stomach d. descending colon e. kidney 48. Which of the following is TRUE regarding low serum selenium concentration? a. inversely associated with increased risk of heart disease and cancer b. can cause frequent nosebleeds c. is associated with leukonychia d. can cause chronic congestion e. is related to Wilson’s disease

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Chapter 13: Essential Trace and Ultratrace Minerals 49. Which element disrupts normal zinc functions if present in high concentrations in the body? a. cadmium b. chromium c. selenium d. molybdenum e. phosphorus 50. Hemochromatosis is associated with which mineral? a. iron b. copper c. selenium d. manganese e. phosphorus 51. Which of these is NOT true regarding selenium deficiency? a. Individuals with HIV are at a decreased risk of selenium deficiency. b. Some deficiency symptoms include poor growth, muscle pain, and weakness. c. It is linked to Kashin-Beck disease. d. It is linked to Keshan disease. e. Widespread selenium deficiency occurs in certain regions of the world.

Indicate whether the statement is true or false.

52. Iron regulatory protein (IRE-BP) is activated (i.e., to bind IREs) by iron. a. True b. False 53. Endocytosis is the mechanism for a transferrin receptor transporting iron into a cell. a. True b. False 54. Hemochromatosis is a genetic disorder that ultimately results in the excessive accumulation of iron in certain tissues. a. True b. False 55. Zinc deficiency could result in a secondary deficiency of folate, because polyglutamate hydrolase is a zinc-containing enzyme. a. True b. False 56. Albumin carries zinc and copper in the portal circulation to all tissues in the body. a. True b. False

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Chapter 13: Essential Trace and Ultratrace Minerals 57. Metallothionein is a storage protein for excess zinc, copper, and iron. a. True b. False 58. Copper deficiency can result in iron-deficiency anemia. a. True b. False 59. Overall, assessing the status of zinc is difficult and requires multiple measures. a. True b. False 60. Calcium compounds have the ability to enhance the absorption of iron. a. True b. False 61. Meat and shellfish products are excellent sources of copper. a. True b. False 62. If started within the first 24 hours of the onset of cold symptoms, zinc supplementation may reduce the duration and severity of the symptoms. a. True b. False 63. Leukonychia (whitening of the nail bed) is associated with selenium deficiency. a. True b. False 64. There is no associated toxicity with selenium. a. True b. False 65. Serum or plasma selenium concentrations are widely used for assessment. a. True b. False

66. List five dietary factors that influence iron absorption and indicate what each factor does.

67. Discuss the following measurements of red blood cells, telling what they are and how they are used in assessment of iron nutriture: hemoglobin, hematocrit, MCV, MCH, MCHC. 68. Explain the influences of zinc on carbohydrate metabolism, BMR, and taste.

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Chapter 13: Essential Trace and Ultratrace Minerals 69. Protein Regulation by Minerals: Zinc, copper, and iron regulate the expression of specific proteins, particularly those that are involved in ensuring cells receive these minerals, and those involved in preventing any toxicity associated with too much of a given mineral. Describe how excess zinc (or copper, but not both) and iron regulate the expression of a protein involved in their storage. Be specific—name any proteins and define all abbreviations.

70. Certain foods have been classified as containing goitrogens. List three of these foods and tell how they affect iodide uptake in the thyroid.

71. Detail the absorption of iodine. Be sure to include the tissues where iodine ends up after absorption.

72. Describe the transport of chromium and explain the absorption process.

73. Discuss the sources of chromium, including both food and supplement forms.

74. Discuss the factors influencing chromium absorption.

75. Explain the interactions of Coumadin and vitamin K.

Indicate the answer choice that best completes the statement or answers the question.

76. What is the most biologically active form of chromium found in the body? a. GLUT-4 b. tyrosine kinase c. cystolic acid d. chromate e. chromodulin 77. How is most chromium excreted? a. urine b. feces c. sweat d. respiration e. chromium is stored in the liver and not excreted 78. What is the current clinical test used to assess chromium status? a. 24-hour urine collection b. plasma concentrations c. stool sample d. sweat test e. currently no specific tests are available to determine chromium status 79. Which of the following foods would have the highest content of iodine? a. whole wheat bread b. shrimp c. legumes

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Chapter 13: Essential Trace and Ultratrace Minerals d. nuts e. pork 80. Which minerals have an important link to thyroid function? a. iodine and selenium b. chromium and copper c. iron and zinc d. manganese and molybdenum e. phosphorus and calcium 81. Which mineral’s toxicity may occur from overeating kelp? a. zinc b. selenium c. copper d. iodine e. iron 82. What are the best food sources of manganese? a. lean protein b. coffee c. red meat d. milk and dairy e. plant foods and shellfish 83. Which of the following interactions would most likely be caused by anticonvulsants such as phenobarbital used to treat seizures? a. poor absorption of nutrients such as iron b. poor absorption of the drug when taken with grapefruit c. reduced metabolism of vitamins d. enhanced excretion of potassium and other electrolytes e. decreased sweat 84. Which of the following is NOT true regarding molybdenum excretion? a. most is excreted as molybdate in the urine b. urinary excretion increases as dietary molybdenum intake increases c. little molybdenum is retained in the body d. the kidneys are responsible for molybdenum homeostasis e. large amounts of the mineral are excreted in the feces and sweat 85. Which mineral has a Tolerable Upper Intake Level of 2 mg/day? a. molybdenum b. iron

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Chapter 13: Essential Trace and Ultratrace Minerals c. copper d. zinc e. selenium 86. Which vitamin deficiency would most likely happen in a patient that has been on 18 months of parenteral nutrition? a. iodine b. zinc c. copper d. molybdenum e. iron 87. Which drug is most likely to interact with vitamin D and folate? a. anticonvulsants b. antibiotics c. immunosuppressants d. loop diuretics e. bile-acid sequestrants 88. Which of the following is NOT true regarding people taking MAOIs. a. problems arise when people on this drug eat foods high in amines, especially tyramine or histamine b. poor absorption of the drug when taken with grapefruit c. they should not eat aged cheese d. they should avoid smoked, salted, or pickled fish e. they should avoid red wines including Chianti 89. Which of the following is NOT true regarding loop diuretics? a. used to treat high blood pressure b. help to preserve dietary potassium c. promote the urinary excretion of sodium and water d. dietary replacement of minerals is important when taking this drug e. may increase the urinary losses of potassium chloride, thiamin, zinc, and magnesium

Indicate whether the statement is true or false.

90. Nutrient-drug interactions caused by consuming amines in foods such as aged cheeses while also taking monoamine oxidase inhibitors used to treat depression are most likely to result in high blood pressure and cardiac dysrhythmia. a. True b. False

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Chapter 13: Essential Trace and Ultratrace Minerals Answer Key 1. d 2. b 3. c 4. a 5. c 6. a 7. a 8. b 9. a 10. c 11. d 12. b 13. d 14. b 15. a 16. c 17. c 18. b 19. c 20. d 21. d 22. c 23. a 24. d 25. a

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Chapter 13: Essential Trace and Ultratrace Minerals 26. b 27. c 28. a 29. e 30. d 31. c 32. a 33. a 34. b 35. d 36. a 37. d 38. d 39. b 40. a 41. c 42. d 43. b 44. c 45. a 46. d 47. a 48. c 49. a 50. a 51. a

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Chapter 13: Essential Trace and Ultratrace Minerals 52. False 53. True 54. True 55. True 56. True 57. False 58. True 59. True 60. False 61. True 62. True 63. True 64. False 65. True 66. Grading rubric – answer should include the following items: • • • • •

Sugars serve as ligands that help absorption of iron.

Acids (lactate, ascorbate, citrate) act as reducing agents to increase absorption.

Meat, poultry, and fish promote absorption, although the mechanism is unclear.

Phytic acid and oxalic acid both form insoluble complexes with iron that keep it from being absorbed.

Antacid medications inhibit absorption by making the environment more alkaline.

67. Grading rubric – answer should include the following items: • • •

•

Hemoglobin is the amount of iron-containing protein found in red blood cells per unit, usually deciliter or liter, of blood. When this drops below normal, anemia occurs.

Hematocrit is a measurement of the proportion of the total blood volume that is red blood cells. When this drops below normal, anemia occurs.

MCV is mean corpuscular volume and indicates the size of the red blood cell. If cell size is large, then macrocytic anemia may indicate a folate or B12 deficiency. Microcytic anemia or small cell size may indicate iron-deficiency anemia.

MCH is mean corpuscular hemoglobin and indicates the average hemoglobin content of each cell. MCHC is mean corpuscular hemoglobin concentration and indicates the amount of hemoglobin per deciliter of red blood cells. If

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Chapter 13: Essential Trace and Ultratrace Minerals MCH and MCHC are low, iron-deficiency anemia is indicated.

68. Grading rubric – answer should include the following items: Zinc is needed by pancreatic beta cells for production of insulin and thus influences carbohydrate metabolism. Zinc deficiency causes impaired glucose tolerance. Zinc is important for thyroid hormone production and so zinc deficiency can result in a lower BMR. Zinc is a component of gustin, which is important for perception of taste sensations.

69. For Zn and Cu, as the intracellular concentration increases, they bind to metal-binding protein in the nucleus, which in turn binds to the metal response element of specific regions of DNA. One of these regions is present for the metallothionein, resulting in increased transcription. Thus, high levels of Zn and/or Cu induce the expression of a protein that can serve as a storage site and prevent toxicity of these metals. Cu can use the same mechanism to increase transcription of superoxide dismutase.

For iron, to prevent toxicity one needs to increase the abundance of ferritin as iron concentrations rise in the cell.

However, this is done at a posttranscriptional level (i.e., increasing the translation of existing mRNA for ferritin). High iron levels result in inactive IRP, which does not bind to the IRE present in the 5' untranslated region of ferritin mRNA, allowing it to be translated at a greater rate. In contrast, when iron levels are low, IRP is active, binds the ferritin mRNA IRE, and inhibits translation.

70. Grading rubric – answer should include the following items: Foods of the cabbage family (broccoli, cauliflower, kale, rutabaga, turnips) contain glucosinolates, which compete with iodide for uptake into the thyroid gland. Cassava contains linamarin (also known as goitrin), which breaks down into thiocyanate, which competes with iodide for uptake into the thyroid gland. Lima beans, flaxseed, linseed, sorghum, and sweet potatoes also contain cyanogenic glucosides similar to linamarin.

71. Grading rubric – answer should include the following items: Iodide is absorbed predominantly in the stomach and secondarily from the duodenum. Most ingested iodide (90%) is absorbed, after which free iodide appears in the blood. At this point, it is capable of permeating all tissues, although it actually concentrates in the thyroid gland. Lesser amounts appear in the ovaries, skin, and salivary, gastric, and mammary glands.

72. Grading rubric – answer should include the following items: Chromium is transported in the blood the same way that iron is transported. That is, it is bound to transferrin. Because iron may be attached to the transferrin, thus not leaving any space for the chromium, it is believed that albumin takes over the transport of chromium. In addition, if chromium is present in high concentrations, globulins and lipoproteins also transport the mineral. It is also possible that some unbound chromium circulates in the blood. In order to enter into cells, the chromium is taken in by the process of endocytosis and is released from the endosome once it is inside of the cell.

73. Grading rubric – answer should include the following items: In foods, chromium exists in the trivalent form. Few foods, however, have been analyzed to accurately quantify chromium content; this task is complicated by the variability of chromium within foods. Good dietary sources of chromium are generally thought to include meats and grains- especially whole grains along with some fruits and vegetables. Relatively large amounts of chromium may be present in some red wines and in selected spices such as cinnamon, cloves, bay leaves, and turmeric as well as in tea, beer, and yeast preparations.

Chromium is available in multivitamins and supplements as inorganic salts and as an organic compound complexed with acetate, nicotinate, citration picolinate or amino acids. The bioavailability of the inorganic salt chromium chloride is lower than the organic complexes.

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Chapter 13: Essential Trace and Ultratrace Minerals 74. Grading rubric – answer should include the following items: Like that of other trace minerals, the absorption of chromium may be influenced by dietary factors. Withing the stomach, amino acids or other molecules may chelate chromium. Amino acids such as phenylalanine, methionine, and histidine act as chelators to improve chromium absorptions. These chelations typically help chromium remain soluble and prevent olation once it reaches the alkaline pH of the small intestine. Lipophilic compounds such as picolinate may enhance Cr3+ absorption through the cell’s lipid membrane. Vitamin C and niacin may also enhance chromium absorption.

75. Grading rubric – answer should include the following items: A nutrient known to antagonize the action of Coumadin (warfarin) is vitamin K. Coumadin is an anticoagulant drug.

Coumadin works by inhibiting reactions in the vitamin K cycle that generate the active form of vitamin K needed for blood clotting. By inhibiting the production of active vitamin K, the drug prolongs the clotting time of blood. Large amounts of vitamin K oppose the actions of the drug, promoting blood clotting, and leading to drug resistance. Eating large quantities of foods rich in vitamin K, including green vegetables, some legumes, and liver should be avoided when on this medication.

76. e 77. a 78. e 79. b 80. a 81. d 82. e 83. c 84. e 85. a 86. d 87. a 88. b 89. b 90. True

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Chapter 14: Nonessential Trace and Ultratrace Minerals

Indicate the answer choice that best completes the statement or answers the question.

1. Which micromineral plays a contributing role in the formation of hydroxyapatite crystals that are more resistant to acid erosion? a. arsenic b. selenium c. fluoride d. nickel e. boron 2. Which of the following interacts with fluoride in such a way as to inhibit absorption? a. aluminum b. phosphate c. calcium d. sodium e. boron 3. Which mineral was discovered in the early 1800s and named for the Swedish goddess of beauty and fertility? a. arsenic b. cobalt c. boron d. vanadium e. fluoride 4. Which ultratrace element is important to reduce dental caries? a. boron b. arsenic c. vanadium d. nickel e. fluoride 5. Which Tolerable Upper Intake Level ranges from 1.3 mg/day for children age 1-3 to 10 mg/day for children age 8 years to adults? a. silicon b. vanadium c. arsenic d. boron e. fluoride 6. How would you monitor fluoride to determine toxicity? a. urinary fluoride concentration b. stool sample c. white blood cell

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Chapter 14: Nonessential Trace and Ultratrace Minerals d. sweat test e. skin scraping 7. What food sources tend to contain the most fluoride? a. whole grain breads b. green leafy vegetables c. citrus fruit d. teas and seafood e. dairy 8. What is the primary dietary source of fluoride? a. milk b. community drinking water c. enriched orange juice d. green leafy vegetables e. pork 9. Which ultratrace element was used as a preservative for meat, fish, and dairy products in the early 1900s, considered dangerous for humans in the 1920s, and is considered beneficial for humans today? a. cobalt b. arsenic c. boron d. vanadium e. fluoride 10. Which of the following groups of foods are richest in boron, providing 1.0–4.5 mg/100 g? a. raisins, legumes, nuts, and avocados b. pork, beef, and poultry c. milk, butter, cheese, and yogurt d. fish and shellfish e. tea 11. Which ultratrace element effects the composition, structure, and strength of bones as well as cell membrane stability and inflammation? a. vanadium b. cobalt c. arsenic d. boron e. silicon 12. Boron is associated with which of the following functions? a. metabolism of methionine and methylation of DNA b. bone development and mediation of the inflammatory response

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Chapter 14: Nonessential Trace and Ultratrace Minerals c. synthesis of glucosamine, chondroitin sulfate, and collagen d. insulin action e. assists with lipid metabolism and storage 13. Because of its anti-inflammatory actions, which element may reduce the severity of inflammation associated with injury or infection? a. cobalt b. boron c. silicon d. arsenic e. silicon 14. When did most drinking water become fluorinated in the United States? a. 1980 b. 1945 c. 1930 d. 1920 e. 1890 15. What symptoms have been noted in animals that have fluoride deficiency? a. infertility and growth issues b. cardiac arrhythmias c. impaired memory function d. decreased collagen e. bluish-gray tint on skin 16. What is a fluoride toxicity known as? a. fluoridthmia b. beriberi c. pellagra d. fluoritis e. fluorosis 17. Which mineral has beneficial effects on the brain, bones, and the immune system? a. boron b. cobalt c. silicon d. nickel e. silicon 18. Which of the following is NOT true regarding fluoride? a. fluoride toxicity is known as pellagra b. excessive fluoride for prolonged time periods can cause bone deformities

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Chapter 14: Nonessential Trace and Ultratrace Minerals c. a “pea-sized” amount of fluoridated toothpaste is recommended for children d. doses of 15 mg/kg of body weight can be fatal e. acute toxicity manifests as nausea, vomiting, and diarrhea 19. Which element is second only to oxygen in abundance on earth? a. nickel b. vanadium c. silicon d. cobalt e. manganese 20. What foods are rich sources of silicon? a. whole grains and root vegetables b. coffee and beer c. milk and milk products d. meats, poultry, and fish e. teas and coffee 21. Which element has a positive influence on collagen synthesis and bone mineralization? a. silicon b. vanadium c. arsenic d. nickel e. fluoride 22. What inhibits the absorption of silicon? a. iron b. lactose c. dietary fiber d. citrus fruit e. calcium 23. The major detrimental effect of a long-term excess of dietary silicon, usually in the form of antacids, is what? a. cancer b. asthma c. diabetes d. kidney stones e. dental caries 24. What are the richest dietary sources of vanadium? a. fats and oils b. cereal and grain products c. sweeteners

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Chapter 14: Nonessential Trace and Ultratrace Minerals d. milk products e. teas and coffee 25. Which ultratrace element enters the cell through transport systems for phosphate, with which it competes? a. nickel b. boron c. vanadium d. cobalt e. fluoride 26. Which ultratrace element, in pharmacological quantities, mimics the action of insulin? a. boron b. silicon c. nickel d. vanadium e. cobalt 27. An ultratrace element that can inhibit many systems that require phosphate, such as phosphotransferases, is what? a. nickel b. arsenic c. vanadium d. boron e. cobalt 28. What ultratrace element has been shown to inhibit Na+/K+-ATPase function and the absorption of amino acids at higher concentrations? a. vanadium b. arsenic c. cobalt d. boron e. fluoride 29. Toxicity of which element results in green tongue, diarrhea, and GI cramping? a. vanadium b. silicon c. arsenic d. boron e. cobalt 30. Which ultratrace element is a constituent of vitamin B12? a. arsenic b. vanadium c. boron

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Chapter 14: Nonessential Trace and Ultratrace Minerals d. cobalt e. fluoride 31. Which ultratrace element is not required by humans in its ionic form, but is a necessary component of the coenzyme form of a vitamin? a. iron b. boron c. cobalt d. vanadium e. silicon 32. Which mineral is contained in a preformed metallovitamin essential for humans that cannot be synthesized from dietary sources? a. cobalt b. silicon c. nickel d. boron e. fluoride 33. Fish, sardines with bones, clams, lobster, crab, and shrimp are good sources of what? a. cobalt b. fluoride c. vanadium d. silicon e. boron 34. The form of fluoride in toothpaste is what? a. hydrofluoric acid b. calcium fluoride c. potassium fluoride d. sodium fluoride e. fluoric acid 35. Before it is absorbed, fluoride in foods, often bound to proteins, must be hydrolyzed by what? a. pepsin b. amylase c. lipase d. ATPase e. lactose 36. Which mineral replaces some of the hydroxide ions in hydroxyapatite to help protect against cavities in teeth? a. cobalt b. vanadium c. fluoride

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Chapter 14: Nonessential Trace and Ultratrace Minerals d. silicon e. silver 37. What are some symptoms of acute boron toxicity? a. double vision b. decreased taste and smell c. tachycardia d. headache and dizziness e. nausea, vomiting, and diarrhea 38. What are good dietary sources of silicon? a. milk b. cottage cheese c. tofu d. bananas, pineapple, and mango e. pork 39. In which medications is silicon present in? a. antacids b. anticoagulants c. antibiotics d. topical burn ointments e. ibuprofen 40. Which statement is true regarding silicon excretion and intake? a. Silicon is excreted via the urine as silica acid. b. Silicon excretion happens fairly slowly. c. Silicon excretion is significantly correlated with dietary silicon intake. d. Silicon excretion has no impact on dietary silicon intake. e. Silicon is not excreted, but rather stored in the liver.

41. Silicon in water and most beverages is found as what? a. silica b. orthosilicic acid c. silicate d. asbestos e. silicosis 42. Which element is found as a contaminant in lipsticks, soap, some antibiotics, and gastric antacids? a. cobalt b. arsenic c. silicon

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Chapter 14: Nonessential Trace and Ultratrace Minerals d. boron e. fluoride 43. It has been suggested that which element modulates osteoblast and/or osteoclast activity in bones? a. boron b. arsenic c. fluoride d. nickel e. cobalt 44. Which element is thought to work by its interactions with SAM and NAD+? a. vanadium b. silicon c. boron d. nickel e. fluoride 45. Acute toxicity with which element causes nausea, vomiting, diarrhea, dermatitis, and lethargy? a. arsenic b. boron c. cadmium d. vanadium e. silicon 46. Nausea, vomiting, diarrhea, acidosis, and cardiac arrhythmias are associated with acute toxicity from what? a. arsenic b. vanadium c. nickel d. fluoride e. silicon 47. What are the characteristics of silicosis? a. indentations in nailbeds b. bluish gray tint to skin c. weakened esophageal sphincter d. damage to renal function e. scarring of the lungs 48. The requirements for silicon are mostly unknown, although estimates range from what? a. 50-75 mg/day b. 30-50 mg/day c. 10-25 mg/day d. 5-10 mg/day

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Chapter 14: Nonessential Trace and Ultratrace Minerals e. 1-5 mg/day 49. There is little evidence that cobalt plays a role in human nutrition. However, it is part of a metallovitamin that is crucial for human survival. That vitamin is . a. vitamin B6 b. vitamin B3 c. vitamin B12 d. vitamin B1 e. vitamin B9 50. Antacids, antidiarrheal agents, and analgesics often have which element added? a. cobalt b. nickel c. vanadium d. silicon e. fluoride

Indicate whether the statement is true or false.

51. Even though fluoride is a gaseous chemical, it is usually found bound to a metal, nonmetal, or organic compound. a. True b. False 52. Although fluoride is used to strengthen teeth and bones, fluoride toxicity (fluorosis) is associated with an increased bone fracture risk. a. True b. False 53. Silicosis occurs from the inhalation of particulate crystalline silica and silicates including quartz and asbestos. a. True b. False 54. Studies in humans suggest silicon improves bone strength. a. True b. False 55. Cobalt was used to preserve foods such as fish, meat, cream, and butter for over 50 years. a. True b. False 56. More than 85% of ingested boron is absorbed as boric acid by passive diffusion. a. True b. False

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Chapter 14: Nonessential Trace and Ultratrace Minerals 57. Boron deficiency may affect attention, mental alertness, and memory. a. True b. False 58. Boron may alter the ability of some hormones to exert their effects on target cells. a. True b. False 59. Once absorbed, orthosilicic acid is found mostly free in the blood. a. True b. False 60. Silicon is involved in bone and connective tissue formation. a. True b. False 61. A Tolerable Upper Level for silicon has been established in humans. a. True b. False 62. Quartz is possibly the most well-known form of silicon in nature. a. True b. False 63. Table salt may contain silicon to prevent caking in damp weather. a. True b. False 64. Generally, silicon concentrates in the body’s connective tissue, such as bone, tendons, and cartilage. a. True b. False 65. Vanadium is a useful supplement to aid in glucose management by diabetics. a. True b. False

66. Discuss how vanadium is excreted.

67. Describe the mechanism by which boron is thought to bring about the beneficial effects of inhibiting inflammation and positively influencing bone composition, structure, and strength.

68. Explain the physiological role of silicon in normal growth and bone development.

69. Describe the pharmacological effects of vanadium.

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Chapter 14: Nonessential Trace and Ultratrace Minerals 70. Although all produce symptoms of toxicity, not all of the important trace elements have a Tolerable Upper Intake Level established. Give the UL and/or the toxicity symptoms of boron, silicon, and vanadium.

71. What is different about cobalt as an ultratrace mineral as compared to the other ultratrace minerals in regard to human nutrition?

72. Detail why children excrete less fluoride in their urine that do adults? How is fluoride absorbed?

73. How does boron exert its effect on body functions?

74. Describe the absorption of vanadium.

75. Describe the role that cobalt plays in human nutrition.

Indicate the answer choice that best completes the statement or answers the question.

76. What is the development of bluish skin and nails resulting from ingestion of silver over a period of time called? a. ichthyosis b. argyria c. progeria d. urticaria e. beriberi 77. The Dietary Supplement Health and Education Act (DSHEA) of 1994 requires that manufacturers do what? a. secure prior approval to sell their products b. demonstrate that the supplements are safe c. provide a disclaimer on the label stating that “this statement has not been evaluated by the Food and Drug Administration” d. provide proof of the dietary supplement’s effectiveness e. ensure everything on the ingredient list is correct 78. Which of the following would NOT be a red flag of junk science? a. dire warnings of danger from a single product or regimen b. lists of “good” and “bad” foods c. recommendations from studies that ignore individual or group differences d. recommendations based on peer-reviewed studies e. claims are “too good to be true” 79. Why are manufacturers of dietary supplements not required to secure approval to sell their products? a. because they are not medicines b. because they are always safe c. because they actually are not effective d. because they are sold in very low doses e. because they cannot be harmful 80. Nanoparticles have a particle size between

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Chapter 14: Nonessential Trace and Ultratrace Minerals a. 1-100 nm b. 10-200 nm c. 100-200 nm d. 200-400 nm e. 400-500 nm 81. What is the Tolerable Upper Intake Level that has been established for vanadium per day? a. 1.0 mg b. 1.8 mg c. 10 mg d. 15 mg e. no Tolerable Upper Intake Level has been established 82. Why was a clinical trial using vanadium supplements for adults with Type 2 diabetes discontinued? a. subjects started turning bluish-gray b. adverse effects on the kidneys c. adverse effects on the lungs d. increase in fasting blood glucose was observed e. it was found to be effective 83. What is the established method to assess vanadium status? a. leukocyte count b. there have been no methods established c. stool sample d. sweat test e. urine 84. Which of the following is true regarding cobalt? a. it is part of vitamin B12 b. requirements for humans are in the ionic form c. it is part of vitamin B9 d. it is found primarily in teeth e. it is important for bone formation 85. What is an effect of colloidal silver supplementation? a. hyperkalemia b. hypokalemia c. argyria d. beriberi e. pellagra

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Chapter 14: Nonessential Trace and Ultratrace Minerals 86. When was the Dietary Supplement Health and Education Act (DSHEA) passed into law? a. 1914 b. 1930 c. 1965 d. 1994 e. 2001 87. Silver has been shown helpful in what? a. digestion b. improved memory c. cardiovascular health d. type 2 diabetes e. topical ointments 88. What is the best source of information for recalled products? a. FDA b. local state government offices c. whitehouse.gov d. CDC e. USDA 89. Which products are usually targeted first by the FDA and Federal Trade Commission? a. products that present a direct health threat to consumers b. products that present an indirect health threat to consumers c. products that claim to be organic d. products that claim to be non-GMO e. products that a large proportion of people take 90. Which of the following is true of the U.S.P. (U.S. Pharmacopoeia) symbol? a. is a designation of non-GMO b. can be purchased for a product for $25,000 c. can only be used for fruits and vegetables d. is a designation of organic products e. is a designation that the manufacturer followed established standards

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Chapter 14: Nonessential Trace and Ultratrace Minerals Answer Key 1. c 2. c 3. d 4. e 5. e 6. a 7. d 8. b 9. c 10. a 11. d 12. b 13. b 14. b 15. a 16. e 17. a 18. a 19. c 20. a 21. a 22. c 23. d 24. b 25. c

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Chapter 14: Nonessential Trace and Ultratrace Minerals 26. d 27. c 28. a 29. a 30. d 31. c 32. a 33. b 34. d 35. a 36. c 37. e 38. d 39. a 40. c 41. b 42. d 43. a 44. c 45. b 46. d 47. e 48. c 49. c 50. d 51. True

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Chapter 14: Nonessential Trace and Ultratrace Minerals 52. True 53. True 54. False 55. False 56. True 57. True 58. True 59. True 60. True 61. True 62. True 63. True 64. True 65. True 66. Grading rubric – answer should include the following items: Renal excretion is the major route for the elimination of absorbed vanadium, with urinary vanadium excretion occurring in amounts generally less than 0.8 ug/day. Also, small amounts of vanadium are excreted in the bile.

67. Grading rubric – answer should include the following items: Boron facilitates the production of anti-inflammatory cytokines and other molecules. Bone composition, structure and strength are positively influenced possibly through nodulation of osteoblast and or osteoclast activity. In addition, it enhances extracellular matrix turnover.

68. Grading rubric – answer should include the following items: Silicon likely plays a role in both metabolism and structure of bone. It influences both formation and growth, including mineralization, calcification, and crystallization. It also enhances collagen synthesis. This aids in bone growth because collagen is present in high concentrations in bone.

69. Grading rubric – answer should include the following items: In pharmacological amounts, vanadium mimics the action of insulin by stimulating glucose uptake by moving GLUT4 transporters to the cell membrane, enhancing glucose uptake, and stimulating glycogen and lipid synthesis while it inhibits gluconeogenesis and lipolysis. Vanadium improves insulin sensitivity and reduces serum glucose concentrations and hemoglobin A1c.

70. Grading rubric – answer should include the following items:

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Chapter 14: Nonessential Trace and Ultratrace Minerals Boron – UL is 20 mg/day. Acute toxicity: nausea, vomiting, diarrhea, dermatitis, and lethargy. Chronic toxicity: nausea, poor appetite, anemia, dermatitis, and seizures.

Silicon – No UL. Toxicity from silicon has been associated with the formation of kidney stones; however, it is frequent, chronic (years) use of large amounts of silicon-containing antacids that appears to contribute to the rare development of kidney stones. Toxicity of silicon has also been associated with diminished activities of several enzymes that prevent free radical damage, including glutathione peroxidase, superoxide dismutase, and catalase. Silicosis occurs from the inhalation of dust high in silica; the condition is characterized by a progressive fibrosis of the lungs that leads to respiratory problems.

Vanadium – UL is 1.8 mg/day. Mild toxicity: green tongue syndrome, diarrhea, and gastrointestinal cramps. Chronic toxicity (as seen in miners): hypertension, respiratory tract irritation, neurological disorders, and hepatic, cardiac, and renal damage.

71. Grading rubric – answer should include the following items: Because there is little evidence suggesting that cobalt itself is necessary in human nutrition, its importance is its inclusion in the vitamin B12 molecule. This vitamin is crucial to human survival and, therefore, without cobalt the vitamin would not exist. Studies have shown that ionic cobalt can substitute for other metals in metalloenzyme activity in vitro, but there is no evidence to show that this occurs in vivo.

72. Grading rubric – answer should include the following items: Healthy children continue to grow during their childhood years. Fluoride is absorbed from the stomach and small intestine by passive diffusion. The absorption rate is nearly 100% and happens within 90 minutes of ingestion. Most fluoride, although distributed throughout the body and taken up by several different tissues, is more highly concentrated in the bones and teeth. Because children’s bones are growing, they incorporate more fluoride into the skeleton and excrete less in the urine than do normal adults.

73. Grading rubric – answer should include the following items: Boron most likely exerts its effect on several body functions by interacting with S-adenosylmethionine (SAM) and nicotinamide adenine dinucleotide (NAD+). An example is as boron binds to NAD+, intracellular signaling pathways are affected and may inhibit calcium release from the endoplasmic reticulum into the cell cytosol. It’s also possible that boron may form complexes with cell membrane components such as glycoproteins, glycolipids, and phosphoinositides.

These types of activities suggest that boron may alter the ability of some hormones to act on their target cells.

74. Grading rubric – answer should include the following items: The absorption of vanadium varies with its oxidation states. Vanadate may be reduced to the tetravalent vanadyl in the acidic environment of the stomach before being absorbed by diffusion in the proximal small intestine. The vanadate may also be absorbed directly via the same anion transport career system as used by phosphate and then with myosin and ADP and inhibit interaction with actin to affect muscle function. Vanadium’s interaction with protein kinases and phosphatases disrupt signal pathways, cellular metabolism, and numerous physiological processes.

75. Grading rubric – answer should include the following items: Cobalt is part of vitamin B12 (cobalamin). Ionic cobalt can substitute for other meals in metalloenzyme activity in vitro, but no evidence exists that it acts in that capacity in vivo. Cobalt is unique among the elements, as the requirement in humans is not for the ionic form but for the preformed metallovitamin that cannot be synthesized from dietary metal.

Therefore, it is the vitamin B12 content of the foods and the diet that is important, rather than the actual cobalt.

76. b 77. c

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Chapter 14: Nonessential Trace and Ultratrace Minerals 78. d 79. a 80. a 81. b 82. b 83. b 84. a 85. c 86. d 87. e 88. a 89. a 90. e

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