To download the complete and accurate content document, go to: https://testbankbell.com/download/biochemistry-6th-edition-garrett-test-bank/
1. Carbohydrate characteristic chemical features include all EXCEPT:
a. the potential to form multiple hydrogen bonds.
b. the existence of one or more asymmetric centers.
c. the capacity to form polymeric structures.
d. the ability to exist in either linear or ring structures.
e. all are true.
ANSWER: e
2. Which of the following sugars is an aldopentose?
a. galactose
b. ribulose
c. ribose
d. xylulose
e. mannose
ANSWER: c
3. If carbon 1 is the carbonyl group of an aldohexose, which carbon determines if the sugar is a D- or L- stereoisomer?
a. 1
b. 2
c. 3
d. 4
e. 5
ANSWER: e
4. The enantiomer of D-mannose would be:
a. D-galactose.
b. L-glucose.
c. D-glucose.
d. L-mannose.
e. L-arabinose.
ANSWER: d
5. Mannose is an epimer of:
a. ribose
b. galactose
c. glucose
d. xylose.
e. fructose.
ANSWER: c
6. The formation of cyclic structures in sugars with creation of an additional asymmetric center results from an alcohol reacting with a(n):
a. secondary alcohol.
b. phosphate group.
c. thiol group.
Copyright Cengage Learning. Powered by Cognero. Page
d. aldehyde or ketone.
e. primary alcohol.
ANSWER: d
7. A cyclic hemiacetal with a six-membered oxygen-containing ring is referred to as a(n):
a. aldehyde.
b. pyranose.
c. ketopentose.
d. furanose.
e. sorbitol.
ANSWER: b
8. Glucose most commonly forms which of the following structures?
a. a pyranose using the hydroxyl group on carbon 4
b. a pyranose using the hydroxyl group on carbon 5
c. a pyranose using the hydroxyl group on carbon 6
d. a furanose using the hydroxyl group on carbon 3
e. a furanose using the hydroxyl group on carbon 4
ANSWER: b
9. Which of the following is correctly paired with its most prevalent cyclization product?
a. fructose: pyranose
b. glucose: furanose
c. ribose: pyranose
d. galactose: does not cyclize
e. none of the above
ANSWER: c
10. As a result of mutarotation, D-glucose exists in all of the following forms EXCEPT:
a. L-glucopyranose.
b. β-anomer.
c. free aldehyde.
d. α-anomer.
e. all are true.
ANSWER: a
11. β-D-glucopyranose in the chair form is the most widely occurring form of glucose in nature and it has the following characteristics EXCEPT:
a. forms a six-membered ring.
b. carbon 6 is above the plane of the chair.
c. all of the OH groups are equatorial.
d. the anomeric carbon has a hydroxyl that is below the plane of the chair.
e. all axial positions are occupied by H.
ANSWER: d
Copyright Cengage Learning. Powered by Cognero.
12. All of the statements about the following pairs of sugars are correct EXCEPT:
a. Galactose and mannose are diastereomers.
b. L-galactose and D-galactose are enatiomers.
c. Glyceraldehyde and dihydroxyacetone are stereoisomers.
d. Glucose and mannose are epimers.
e. Glucose has fewer chiral centers than fructose.
ANSWER: e
13. Individuals with uncontrolled diabetes mellitus may have levels of blood so they test their blood for ____.
a. elevated; fructose; gluconic acid
b. depressed; glucose; oxidizing sugars
c. elevated; glucose; fructose
d. depressed; gluconic acid; reducing sugars
e. elevated; glucose; reducing sugars
ANSWER: e
14. Sugar alcohols include all of the following EXCEPT:
a. ribitol.
b. sorbitol.
c. fucose.
d. mannitol.
e. glycerol.
ANSWER: c
15. A constituent of the flavin coenzymes is
a. sorbitol
b. mannitol
c. xylitol
d. ribitol
e. glycerol
ANSWER: d
16. Honey is characteristically composed predominantly of
a. sucrose
b. glucose and ribose
c. fructose and glucose
d. sucrose and sorbitol
e. all of the above
ANSWER: c
17. All of the following are parts of the honeybee's processing of honey EXCEPT:
a. producing a small amount of gluconic acid.
b. concentrating the sugars to a supersaturated state.
c. conversion of some glucose and fructose into sucrose.
d. conversion of most of the fructose to the β-D-fructopyranose form.
Copyright Cengage Learning. Powered by Cognero. Page 3
e. producing an emulsion of glucose hydrate and fructose hydrate crystals in a thick syrup.
ANSWER: c
18. and are glycosamines linked to three-carbon acids at the C-1 or C-3 positions, and components of the polysaccharides of cell higher organisms and bacterial cell walls.
a. Glucosides; galactosides
b. Muramic acid; neuraminic acid
c. Gluconic acid; glucuronic acid
d. Sorbitol; ribitol
e. None of the above
ANSWER: b
19. A glycosidic bond would be present in:
a. β-D-galactosamine.
b. methyl-β-D-glucoside.
c. 2-deoxy-α-D-ribose.
d. β-D-glucose-6-phosphate.
e. α-D-fructose-1, 6-bisphosphate.
ANSWER: b
20. Which of the following disaccharides contains an α (1→4) O-glycosidic bond?
a. sucrose
b. lactose
c. maltose
d. cellobiose
e. cellulose
ANSWER: c
21. All of the following disaccharides are reducing sugars EXCEPT:
a. lactose.
b. maltose.
c. sucrose.
d. cellulose.
e. isomaltose.
ANSWER: c
22. Which of the following explains why the disaccharide sucrose is not a reducing sugar?
a. the primary hydroxyl groups are oxidized to carboxylic acids
b. both anomeric carbons are involved in formation of the glycosidic bond
c. the glycosidic bond is in the α configuration
d. it is composed of a furanose and a pyranose
e. none of the above
ANSWER: b
23. All of the following are homodisaccharides EXCEPT:
Copyright Cengage Learning. Powered by Cognero. Page 4
a. lactose.
b. maltose.
c. isomaltose.
d. cellobiose.
e. all are homodisaccharides.
ANSWER: a
24. Glucuronic acid is formed by oxidation of which carbon of glucose?
a. C-1
b. C-2
c. C-4
d. C-6
e. both a and b
ANSWER: d
25. The cyclization of gluconic acid produces what type of structure?
a. lactam
b. lactone
c. pyranose
d. cyclic ether
e. none of the above
ANSWER: b
26. is typical of the oligosaccharide components found in beans, etc., that are not digested in the stomach, but are digested by bacteria in the intestines causing flatulence.
a. Melezitose
b. Amygdelin
c. Laetrile
d. Stachyose
e. Dextrantriose
ANSWER: d
27. Cellulose is homopolysaccharide composed of linked together by glycosidic bonds.
a. galactose; β-(1→4)
b. galactose; α-(1→4)
c. glucose; β-(1→4)
d. glucose; α-(1→4)
e. none of the above
ANSWER: d
28. Mucopolysaccharides such as form protective coats on animal cells.
a. chitin
b. cellulose
c. glycogen
d. hyaluronic acids
Copyright Cengage Learning. Powered by Cognero.
e. glucuronic acids
ANSWER: d
29. Because osmotic pressure depends only on ____, the osmotic pressure is greatly reduced by formation of polysaccharide molecules from monosaccharide molecules.
a. molecular weight
b. number of hydroxyl groups
c. numbers of molecules
d. numbers of hydrogen bonds
e. none are true
ANSWER: c
30. In plant cells, starch is hydrolyzed by to release and a starch molecule with ____.
a. starch phosphorylase; glucose-1-phosphate; one less glucose unit
b. salivary α-amylase; maltose 1-phosphate; two less glucose units
c. starch phosphorylase; maltose 1-phosphate; two less glucose units
d. α(1→6) glucosidase; glucose-6-phosphate; one less glucose unit
e. starch hydrolase; glucose; one less glucose unit
ANSWER: a
31. Cooked starch is more digestible because:
a. it has been partially hydrolyzed during cooking.
b. the amylopectin is converted to amylose during cooking.
c. the enzymes that hydrolyze the starch are only active when the starch is hot.
d. the starch granules take up water, swell and are more accessible to the enzymes.
e. all are true.
ANSWER: d
32. The enzymes α-amylase and β-amylase can cleave the bonds of amylopectin but not the bonds.
a. α (1→6)-; α (1→4)-
b. β (1→6)-; β (1→4)-
c. α (1→4)-; β (1→4)-
d. α (1→4)-; α (1→6)-
e. α (1→6)-; β (1→4)-
ANSWER: d
33. is an enzyme found in liver and muscle tissue used to catalyze the phosphorolysis of glycogen to ____.
a. β (1→6)-Glucosidase; glucose-1-phosphate
b. α-Amylase; glucose-1-phosphate
c. β-Amylase; glucose
d. Glycogen maltase; maltose
e. Glycogen phosphorylase; glucose-1-phosphate
ANSWER: e
34. All of the following statements about the nature of glycogen are true EXCEPT:
Copyright Cengage Learning. Powered by Cognero.
a. It is a polysaccharide used for storage.
b. It is a branched polymer of linked glucose residues.
c. It has all non-reducing ends.
d. The highly branched structure allows the rapid mobilization of glucose during metabolic need.
e. It is found primarily in the liver and skeletal muscles.
ANSWER: c
35. All are true statements about dextrans EXCEPT:
a. They are used in research laboratories as a support for column chromatography (Sephadex or BioGel).
b. They are repeating units of isomaltose.
c. The branches may be 1→2, 1→3 or 1→4 in various species.
d. They are an important component of dental plaque.
e. All are true.
ANSWER: e
36. Which of the following statements about cellulose fiber is true?
a. It is a linear polymer of β (1→4) glycosidic linked glucose and galactose residues.
b. It is extremely susceptible to hydrolysis.
c. It is water-soluble.
d. It is made up of very weak microfibrils.
e. Intermolecular hydrogen bonds play a major role in stabilization of the microfibrils.
ANSWER: e
37. All are true for cellulose and α-amylose EXCEPT:
a. Both are linear homopolymers of glucose.
b. Both have (1→4) linkages.
c. Both form extended ribbon most stable conformations.
d. Both have extensive intramolecular hydrogen bonding.
e. All are true.
ANSWER: c
38. Cellulose is extremely resistant to hydrolysis, but cellulase catalyzes the hydrolysis and comes from:
a. the pancreas.
b. bacteria that live in the rumen.
c. the liver.
d. H+ secreted into the rumen.
e. the intestinal wall.
ANSWER: b
39. Cellulase is considered a(n) ____.
a. α-(1→4) glucosidase
b. β-(1→4) glucosidase
c. α-(1→6) glucosidase
d. β-(1→4) glucosidase
e. α-(1→1) glucosidase
Copyright Cengage Learning. Powered by Cognero.
ANSWER: b
40. Cellulose and chitin are similar in all of the following ways EXCEPT:
a. Both are polymers of glucose.
b. Both are structural polysaccharides.
c. Both have extended ribbon conformations.
d. Both have extensive hydrogen bonding.
e. All are true.
ANSWER: a
41. All are true for agarose EXCEPT:
a. Forms a double helix with a central core large enough to accommodate large quantities of water.
b. Consists of only a linear component.
c. Is a chain of alternating D-galactose and 3,6-anhydro-L-galactose, with side-chains of 6-methyl-D-galactose.
d. Readily forms gels that are up to 99.9% water.
e. All are true.
ANSWER: b
42. Glycosaminoglycans are unbranched polysaccharides consisting of alternating residues of uronic acid and hexosamine. Which of the following is NOT a glycosaminoglycan?
a. agaropectin
b. heparin
c. dermatan sulfate
d. hyaluronate
e. chondroitin-4-sulfate
ANSWER: a
43. and are found in tendons, cartilage and other connective tissue.
a. Heparin; chondroitins
b. Chondroitins; keratin sulfate
c. Keratin sulfate, dermatan sulfate
d. Hyaluronate, keratin sulfate
e. All are true.
ANSWER: b
44. are important components of the vitreous humor of the eye and of synovial fluid that lubricates the joints.
a. Heparin
b. Hyaluronates
c. Chondroitins
d. Keratin sulfates
e. All are true
ANSWER: b
45. Proteoglycans are a group of macromolecules formed from:
a. proteases and monosaccharides.
Copyright Cengage Learning. Powered by Cognero.
b. proteins and glycosaminoglycans.
c. proteins and polysaccharides.
d. proteases and glycosaminoglycans.
e. proteins and glycogen.
ANSWER: b
46. Which of the following represents an example of a proteoglycan?
a. attachment of several molecules of heparin to the peptide antithrombin III
b. attachment of a Gal-β(1,3)-GalNAc disaccharide to the fish antifreeze protein
c. attachment of a small oligosaccharide to an immunoglobulin
d. attachment of a small antigenic determinant to a membrane bound protein of a cell
e. none of the above
ANSWER: a
47. The core protein of a proteoglycan is noncovalently attached to:
a. oligosaccharides.
b. glycosaminoglycans.
c. keratin sulfate.
d. an outer protein.
e. hyaluronic acid backbone.
ANSWER: e
48. Cartilage-matrix proteoglycan has all of the following properties EXCEPT:
a. responsible for the flexibility and resiliency of cartilage.
b. has a hyaluronic acid binding domain.
c. has reversible hydration-dehydration properties.
d. contains both N-linked and O-linked oligosaccharides.
e. is an integral transmembrane protein.
ANSWER: e
49. Which of the following monosaccharides is an aldose?
d. d
e. none of the above
ANSWER: d
50. Which of the following best describes the glycosidic bond below?
Copyright Cengage Learning. Powered by Cognero. Page 9
a. a b. b c. ca. β(2→4)
b. α(1→3)
c. α(1→4)
d. β(1→3)
e. α(2→4)
ANSWER: c
51. Which of the following statements is true regarding glycogen?
a. the branches are formed by α(2→6) glycosidic bonds
b. glycogen is the primary energy storage molecule for animals
c. most of the glycosidic bonds are α(1→4)
d. glycogen is considered a heteropolysaccharide
e. none of the above are true
ANSWER: c
52. Amylose and glycogen are both glucose polymers, yet they have somewhat different properties. What is one important difference between them?
a. One is made with D-glucose and the other with L-glucose
b. One is used as a structural polymer in insects; the other for energy in plants
c. One contains α glycosidic bonds while the other contains β glycosidic bonds
d. One is a linear polymer while the other is highly branched
e. none of the above explain the difference between amylose and glycogen
ANSWER: d
53. Which of the following would be the correct Haworth projection for β-D-talose (linear form is shown on the left)?
Copyright Cengage Learning. Powered by Cognero.
e. none of the above
ANSWER: d
54. Discuss anomers.
ANSWER: When hemiacetals and hemiketals are formed, the carbon atom that carried the carbonyl function becomes an asymmetric carbon atom. Isomers of monosaccharides that differ only in their configuration about that carbon atom are called anomers, designated as α or β, and the carbonyl carbon is thus called the anomeric carbon. When the hydroxyl group at the anomeric carbon is on the same side of a Fischer projection as the oxygen atom at the highest numbered asymmetric carbon, the configuration at the anomeric carbon is α, as in α-D-glucose. When the anomeric hydroxyl is on the opposite side of the Fischer projection, the configuration is β, as in β-D-glucopyranose.
TOPICS: 7.2 What Are the Structure and Chemistry of Monosaccharides?
55. Discuss the structure of glycogen.
ANSWER: Glycogen is the major form of storage polysaccharide in animals. Glycogen is found mainly in the liver (where it may amount to as much as 10% of liver mass) and skeletal muscle (where it accounts for 1% to 2% of muscle mass). Liver glycogen consists of granules containing highly branched molecules, with α(1 6) branches occurring every 8 to 12 glucose units. Like amylopectin, glycogen yields a red-violet color with iodine. Glycogen can be hydrolyzed by both α- and β-amylases, yielding glucose and maltose, respectively, as products and can also be hydrolyzed by glycogen phosphorylase, an enzyme present in liver and muscle tissue, to release glucose-1-phosphate.
TOPICS: 7.4 What Are the Structure and Chemistry of Polysaccharides?
56. Discuss the glycoproteins and glycolipids that have terminal sialic acids on their oligosaccharide chains.
ANSWER: The oligosaccharide chains of glycoproteins and glycolipids serve as ligands for mammalian sugar-binding proteins and also as receptors for pathogens such as influenza and polyoma virus, for bacteria, and for bacterial toxins when they bind to the host cell. The terminal sugars of most such oligosaccharide chains are sialic acids, the most common being Neu5Ac. The sialic acid-capped oligosaccharides themselves are termed sialosides. Sialosides on glycoproteins and glycolipids mediate aspects of immune responses and leukocyte trafficking to lymph nodes and inflammation sites, among other functions. The biosynthesis of sialosides is carried out by 20 sialyltransferase enzymes that are highly conserved in mammals.
TOPICS: 7.5
57. Explain how proteoglycans make cartilage flexible and resilient.
ANSWER: In cartilage, long filaments of hyaluronic acid are coated with proteoglycan molecules. The hyaluronate chains can be as long as 4 μm and can coordinate 100 or more proteoglycan units. Cartilage proteoglycan possesses a hyaluronic acid–binding domain on the NH2-terminal portion of the polypeptide, which binds to hyaluronate with the assistance of a link protein. The proteoglycan–hyaluronate aggregates are highly hydrated by virtue of strong interactions between water molecules and the polyanionic complex. When cartilage is compressed, water is briefly squeezed out of the cartilage tissue and then reabsorbed when the stress is diminished. This reversible hydration gives cartilage its flexible, shock-absorbing qualities and cushions the joints during physical activities.
58. Briefly explain lectins with an example.
ANSWER: Lectins are a class of proteins that bind carbohydrates with high specificity and affinity. Many of the proteins involved in glycoconjugate formation are lectins. The processes of cell migration, cell–cell interaction, immune response, and blood clotting, along with many other biological processes, depend on information transfer modulated by glycoconjugates. Lectins are the translators of the sugar code Calnexin is an example
Copyright Cengage Learning. Powered by Cognero. Page 11
of a lectin. The carbohydrate that calnexin specifically binds to is glucose. Calnexins act as ligand-selective molecular chaperones in the endoplasmic reticulum.
TOPICS: 7.7 Do Carbohydrates Provide a Structural Code?
Copyright Cengage Learning. Powered by Cognero. Page