Fundamentals of biochemistry life at the molecular level 5th edition voet test bank

Fundamentals of Biochemistry Life at the Molecular Level 5th Edition Voet Test Bank Visit to download the full and correct content document: https://testbankdeal.com/dow nload/fundamentals-of-biochemistry-life-at-the-molecular-level-5th-edition-voet-test-b ank/

Chapter 8: Carbohydrates Matching A) B) C) D) E) F) G) H) I) J) K) L) M) N) O) P

eight deoxy peptidoglycan axial anomers two lactose glyceraldehyde amylopectin epimers sixteen glycogen equatorial chitin hyaluronic acid amylose

1. Glucose, with its four chiral carbon atoms, has ______ possible stereoisomers.

Ans: K Level of Difficulty: Easy Section: 8.1.A Learning objective: Monosaccharides

2. The smallest aldose is ______.

Ans: H Level of Difficulty: Easy Section: 8.1.A Learning objective: Monosaccharides 3. The monosaccharides -D-galactose and -D-galactose are ______.

Ans: E Level of Difficulty: Easy Section: 8.1.A Learning objective: Monosaccharides

1

4. Bulky ring substituents preferentially occupy ______ positions in the chair conformation.

Ans: M Level of Difficulty: Easy Section: 8.1.B Learning objective: Monosaccharides

5. The ______ sugars are monosaccharides in which a hydroxyl group is replaced with a hydrogen atom.

Ans: B Level of Difficulty: Easy Section: 8.1.C Learning objective: Monosaccharides

6. The disaccharide commonly found in dairy products is ______.

Ans: G Level of Difficulty: Easy Section: 8.2.A Learning objective: Polysaccharides 7. ______ is a homopolymer composed of (1-4)-linked N-acetyl-D-glucosamine residues that is the principle structural component of the exoskeleton of various groups of invertebrates.

Ans: N Level of Difficulty: Easy Section: 8.2.B Learning objective: Polysaccharides 8. Both (1→4) and (1→6) bonds can be found in the plant product______.

Ans: I Level of Difficulty: Easy Section: 8.2.C Learning objective: Polysaccharides

2

9. An example of a homopolysaccharide in liver and muscle is ______.

Ans: L Level of Difficulty: Easy Section: 8.2.C Learning objective: Polysaccharides

10. ______ is a heteropolymer composed of D-glucoronate and N-acetyl-D-glucosamine that acts as shock absorber and lubricant.

Ans: O Level of Difficulty: Moderate Section: 8.2.C Learning objective: Polysaccharides

11. The main component of a bacterial cell wall is a ______.

Ans: C Level of Difficulty: Easy Section: 8.3.B Learning objective: Glycoproteins

3

Multiple Choice 12. How many stereoisomers are possible for an aldopentose such as ribose?

A) 2 B) 4 C) 8 D) 16 E) 32 Ans: C Level of Difficulty: Easy Section: 8.1.A Learning objective: Monosaccharides

13. How many stereoisomers are possible for a ketopentose such as ribulose?

A) 2 B) 4 C) 8 D) 16 E) 32 Ans: B Level of Difficulty: Easy Section: 8.1.A Learning objective: Monosaccharides

4

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ This figure is used in questions 14-16

14. Which of the sugars shown in the figure above are L sugars?

A) A and B B) B and C C) C and D D) A and D E) None of the above Ans: C Level of Difficulty: Moderate Section: 8.1.A Learning objective: Monosaccharides

5

15. Which sugar shown in the figure above is the enantiomer of sugar A? A) B B) C C) D D) B and D E) none of the above Ans: C Level of Difficulty: Moderate Section: 8.1.A Learning objective: Monosaccharides

16. Which two sugars shown in the figure above are epimers?

A) A and B B) B and C C) C and D D) A and D E) None of the above Ans: A Level of Difficulty: Easy Section: 8.1.A Learning objective: Monosaccharides

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ This figure is used in questions 17-21.

6

17. Which of the structures shown in the figure above is galactose?

A) A B) B C) C D) D E) None of the above Ans: C Level of Difficulty: Moderate Section: 8.1.A Learning objective: Monosaccharides

18. Which structure(s) shown in the figure above represent reducing sugar(s)?

A) A B) D C) C and D D) A, B, C, and D E) A, B, and C Ans: E Level of Difficulty: Moderate Section: 8.1.A Learning objective: Monosaccharides

19. Which structure shown in the figure above is a ketohexose?

A) A B) B C) C D) D E) None of the above Ans: D Level of Difficulty: Easy Section: 8.1.A Learning objective: Monosaccharides

7

20. Which structure shown in the figure above is ribose?

A) A B) B C) C D) D E) None of the above Ans: A Level of Difficulty: Easy Section: 8.1.A Learning objective: Monosaccharides

21. The structures shown in the figure above are represented as A) Fischer projections.

B) Haworth projections.

C) space-filling projections.

D) ball and stick models.

E) None of the answers above is correct.

Ans: A Level of Difficulty: Easy Section: 8.1.A Learning objective: Monosaccharides

8

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ This figure is used in questions 22-25.

22. Which of the structures shown in the figure above is a glucopyranose?

A) A B) B C) C D) D E) None of the above Ans: A Level of Difficulty: Moderate Section: 8.1.A Learning objective: Monosaccharides

9

23. Which structure shown in the figure above represents a ketose?

A) A B) B C) C D) D E) None of the above Ans: E Level of Difficulty: Moderate Section: 8.1.A Learning objective: Monosaccharides

24. Which structures shown in the figure above represent possible structures of glucose?

A) A B) A and B C) A and C D) A, B, and C E) None of the above Ans: B Level of Difficulty: Moderate Section: 8.1.A Learning objective: Monosaccharides

25. Which structure shown in the figure above represents deoxyribose?

A) A B) B C) C D) D E) None of the above Ans: E Level of Difficulty: Easy Section: 8.1.A Learning objective: Monosaccharides

10

26. Alcohols react with aldehydes to form A) hemiketals.

B) lactones.

C) lactams.

D) glycosides.

E) hemiacetals.

Ans: E Level of Difficulty: Easy Section: 8.1.B Learning objective: Monosaccharides

27. At equilibrium in solution, D-glucose consists of a mixture of its anomers. Which statement most accurately describes this solution?

A) The solution consists of approximately equal amounts of the - and -anomers.

B) The straight-chain form is present in high concentration.

C) The -anomer is more stable and is slightly preferred over the -anomer.

D) The -anomer predominates over the -anomer by a ratio of approximately 2:1.

E) None of the answers above is correct.

Ans: D Level of Difficulty: Moderate Section: 8.1.B Learning objective: Monosaccharides

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ This figure is used in questions 28-30.

11

28. The structure shown in the figure above represents a A) glucopyranose.

B) ribofuranose.

C) myo-inositol.

D) fructofuranose.

E) glucofuranose.

Ans: D Level of Difficulty: Moderate Section: 8.1.B Learning objective: Monosaccharides

29. Which of the carbon atoms shown in the figure above represent the anomeric carbon?

A) A B) B C) C D) D E) E Ans: E Level of Difficulty: Moderate Section: 8.1.B Learning objective: Monosaccharides

30. The configuration around which carbon atom shown in the figure above determines whether this is a D or an L sugar?

A) A B) B C) C D) D E) E Ans: A Level of Difficulty: Moderate Section: 8.1.B Learning objective: Monosaccharides

12

31. The transformation of a monosaccharide into its ______ occurs easily and does not require the assistance of a catalyst.

A) epimer B) anomer C) sugar alcohol D) diastereomer E) none of the above Ans: B Level of Difficulty: Easy Section: 8.1.B Learning objective: Monosaccharides

32. The structure below shows a Fischer projection of D-idose.

Which of the structures below represents -D-idopyranose

Ans: E Level of Difficulty: Moderate Section: 8.1.B Learning objective: Monosaccharides

13

33. The structure below shows -D-gulopyranose.

Which of the structures below represents a Fischer projection of D-gulose?

Ans: C Level of Difficulty: Moderate Section: 8.1.B Learning objective: Monosaccharides

34. Which of the following sugars is not a reducing sugar?

A) glucose B) ribose C) sucrose D) starch E) galactose Ans: C Level of Difficulty: Moderate Section: 8.1.C Learning objective: Monosaccharides

14

35. The figure below shows structures of several types of sugars. Which one is an aldonic acid?

Ans: D Level of Difficulty: Moderate Section: 8.1.C Learning objective: Monosaccharides

36. The figure below shows structures of several types of sugars. Which one is an alditol?

Ans: B Level of Difficulty: Moderate Section: 8.1.C Learning objective: Monosaccharides

15

37. Uronic acids A) are aldoses where the aldehyde is oxidized to a carboxylic acid.

B) are aldoses where the 1° alcohol is oxidized to a carboxylic acid.

C) can be found in the pyranose or furanose forms.

D) A and C are both correct.

E) B and C are both correct.

Ans: E Level of Difficulty: Moderate Section: 8.1.C Learning objective: Monosaccharides

38. The sialic acids A) are important constituents of glycoproteins and glycolipids.

B) are N-acetyl glucosamine derivatives.

C) incorporate a succinic acid derivative.

D) all of the above E) none of the above Ans: A Level of Difficulty: Moderate Section: 8.1.C Learning objective: Monosaccharides

39. The bonding of alcohols to the anomeric center of a carbohydrate results in the formation of a(n) __________ bond.

A) anomeric B) amide C) glycosidic D) ester E) hydrogen Ans: C Level of Difficulty: Easy Section: 8.1.C Learning objective: Monosaccharides

16

40. Which of the structures below represents a glucoside?

Ans: B Level of Difficulty: Easy Section: 8.1.C Learning objective: Monosaccharides

41. A saccharide that has free aldehyde group is called a(n) _____________.

A) ketose B) nonreducing sugar C) reducing sugar D) aldohexose E) alditol Ans: C Level of Difficulty: Easy Section: 8.1.C Learning objective: Monosaccharides 42. D-Allose is an aldohexose. Methylation of which hydroxyl group on -D-allopyranose prevents the molecule from mutarotating to -D-allopyranose?

A) C1 B) C2 C) C3 D) C4 E) C5 Ans: A Level of Difficulty: Easy Section: 8.1.C Learning objective: Monosaccharides

17

43. Which of the following is the most abundant disaccharide?

A) lactose B) cellulose C) α-amylose D) maltose E) sucrose Ans: E Level of Difficulty: Easy Section: 8.2.A Learning objective: Polysaccharides

44. Which of the following is a disaccharide?

A) amylose B) saccharin C) aspartame D) amylopectin E) none of the above Ans: E Level of Difficulty: Difficult Section: 8.2.A Learning objective: Polysaccharides

45. Which of these is not an artificial sweetener?

A) saccharine B) aspartame C) maltose D) acesulfame E) alitame Ans: C Level of Difficulty: Moderate Section: 8.2.A Learning objective: Polysaccharides

18

46. Which of the following statements applies to all artificial sweeteners?

A) Artificial sweeteners cannot be readily metabolized.

B) Artificial sweeteners are peptides and provide important amino acids.

C) Artificial sweeteners have fewer calories than sucrose.

D) Artificial sweeteners are much sweeter than sucrose.

E) all of the above Ans: D Level of Difficulty: Moderate Section: 8.2.A Learning objective: Polysaccharides

47. Which of the following polysaccharides cannot be digested by mammalian salivary, gastric, or pancreatic enzymes?

A) cellulose B) amylopectin C) amylose D) glycogen E) starch Ans: A Level of Difficulty: Easy Section: 8.2.B Learning objective: Polysaccharides

48. Which of the following polysaccharides cannot be digested by mammalian salivary, gastric, or pancreatic enzymes?

A) amylopectin B) amylose C) chitin D) glycogen E) starch Ans: C Level of Difficulty: Easy Section: 8.2.B Learning objective: Polysaccharides

19

49. Which of these polysaccharides is a branched polymer?

A) chitin B) amylose C) cellulose D) amylopectin E) hyaluronic acid Ans: D Level of Difficulty: Moderate Section: 8.2.B Learning objective: Polysaccharides

50. Chitin differs from cellulose due to A) inversion of configuration at the anomeric carbon.

B) sulfonation of the C2 OH group.

C) a much greater prevalence of branching.

D) replacement of the C2 OH group by an acetamido group.

E) replacement of the C6 OH group by an amino group.

Ans: D Level of Difficulty: Easy Section: 8.2.B Learning objective: Polysaccharides

51. Cellulose is A) a linear copolymer of glucose and galactose.

B) a branched polymer of glucose.

C) a linear polymer of glucose with β(1→4) linkages.

D) a linear polymer of glucose with α(1→4) linkages.

E) sometimes called starch.

Ans: C Level of Difficulty: Easy Section: 8.2.B Learning objective: Polysaccharides

20

52. Which polysaccharide is found in a helically coiled conformation?

A) chitin B) α-amylose C) cellulose D) lignin E) none of the above Ans: B Level of Difficulty: Moderate Section: 8.2.C Learning objective: Polysaccharides

53. Which of the following is a mixture of two types of polymers?

A) cellulose B) starch C) chitin D) glycogen E) amylose Ans: B Level of Difficulty: Moderate Section: 8.2.B Learning objective: Polysaccharides

54. Starch is a mixture of A) -amylose and amylopectin.

B) glycogen and amylopectin.

C) glycogen and -amylose.

D) glycogen and cellulose.

E) -amylose and maltose.

Ans: A Level of Difficulty: Moderate Section: 8.2.B Learning objective: Polysaccharides

21

55. Which of the following is an example of a heteropolysaccharide?

A) cellulose B) chitin C) starch D) glycogen E) hyaluronic acid Ans: E Level of Difficulty: Moderate Section: 8.2.D Learning objective: Polysaccharides

56. Glycoproteins A) are only found in bacteria.

B) are extremely homogeneous.

C) are typically less than 1% carbohydrate by weight.

D) are assembled under strict genetic control.

E) exhibit microheterogeneity.

Ans: E Level of Difficulty: Easy Section: 8.3.A Learning objective: Glycoproteins

57. Bacterial cell walls are composed of _____.

A) pectin B) chondroitin sulfate chains C) peptidoglycans D) heparin E) proteoglycans Ans: C Level of Difficulty: Easy Section: 8.3.B Learning objective: Glycoproteins

22

58. N-linked oligosaccharides can be covalently linked to proteins at which amino acid?

A) Gly B) Ser C) Glu D) Tyr E) Asn Ans: E Level of Difficulty: Easy Section: 8.3.C Learning objective: Glycoproteins

59. Which statement about N-linked glycosylation is correct?

A) N-linked oligosaccharides are attached to proteins one sugar at the time in the endoplasmic reticulum.

B) N-linked sugars are attached to proteins as a 14 residue oligosaccharide during translation in the endoplasmic reticulum.

C) N-linked sugars are attached to proteins as a 14 residue oligosaccharide during translation in the cytoplasm.

D) N-linked sugars are attached to proteins as a 14 residue oligosaccharide after translation in the Golgi apparatus.

E) N-linked oligosaccharides are attached to proteins one sugar at the time in the Golgi apparatus.

Ans: B Level of Difficulty: Moderate Section: 8.3.C Learning objective: Glycoproteins

60. Which of the following sequences represents a recognition site for N-linked glycosylation where X is any amino acid except Pro? A) Gln—X—Ser B) His—X—Ser C) Arg—X—Ser D) Asn—X—Ser E) Asp—X—Ser Ans: D Level of Difficulty: Easy Section: 8.3.C Learning objective: Glycoproteins

23

61. O-linked oligosaccharides are commonly attached to the —OH group of _____.

A) ribose B) tyrosine C) lysine D) threonine E) glycine Ans: D Level of Difficulty: Easy Section: 8.3.C Learning objective: Glycoproteins

62. Proteins that bind to specific carbohydrates are called ______.

A) pectins B) oligonucleotides C) glycosaminoglycans D) lectins E) chitins Ans: D Level of Difficulty: Easy Section: 8.3.D Learning objective: Glycoproteins

24

SHORT ANSWER 63. We encounter a great variety of sugars in living organisms. a. Are most carbohydrates in living organisms D or L? b. Draw a Fischer projection of the smallest aldose (include all atoms). c. What is the name of this molecule?

Ans: a. D

b. see drawing c. D-glyceraldehyde Level of Difficulty: Easy Section: 8.1.A Learning objective: Monosaccharides

25

64. We encounter a great variety of sugars in living organisms. a. Draw a Haworth projection of an aldohexose in the pyranose form (include all atoms). b. Draw the Haworth projection of the anomer of the aldose you drew in "a" above. c. Draw a circle around the carbon that determines whether this sugar is a D or an L sugar. d. How many chiral carbon atoms are present in each of the structures drawn in "a" and b" above? e. How many stereoisomers exist for these pyranoses?

Ans: a. see drawing

b. see drawing c. see drawing d. 5 e. 25 = 32 Level of Difficulty: Moderate Section: 8.1.B Learning objective: Monosaccharides

26

65. The picture below shows a Fischer projection of D-glucose.

a. Is glucose and aldose or a ketose? b. What is the name of the molecule that is formed upon oxidation of the aldehyde to a carboxyl group? c. Draw a Fischer projection of D-galactose, which is an epimer of glucose with respect to the C4 position. d. Draw a Haworth projection of -D-glucopyranose. e. What is the name of the linear polymer in which glucopyranose residues are linked to each other through (1→4) glycosidic bonds.

Ans: a. aldose b. D-gluconic acid c. see drawing

d. see drawing e. cellulose Level of Difficulty: Moderate Section: 8.1 and 8.2 Learning objective: Monosaccharides and Polysaccharides

27

66. The drawing below shows the structure of the disaccharide sucrose.

a. What are the names of the two monosaccharides that form sucrose? b. Draw squares around the carbons that determine the designation D or L for each of the monosaccharides. c. Draw circles around the anomeric carbon atoms on the drawing. d. Indicate on the drawing for each of the anomeric carbon atoms whether they are in the  or the  configuration. e. Is sucrose a reducing sugar? Explain your answer in one sentence.

Ans: a. glucose (glucopyranose) and fructose (fructofuranose).

b. see drawing c. see drawing d. see drawing e. Sucrose is a nonreducing sugar because both anomeric carbons are involved in a glycosidic bond.

28