CHAPTER 18: CARBOHYDRATES

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CHAPTER 18: CARBOHYDRATES MULTIPLE CHOICE

1. Which of the following compounds is both an aldose and a hexose? Ans. = C a.

c.

b.

d.

2. Which of the following structures is that of an L-monosaccharide? Ans. = C a.

c.

b.

d.

Testbank General, Organic, Biological Chemistry, 6 th edition 1

3. Which of the following statements concerning chiral centers in specific monosaccharides is

incorrect

? Ans. = B a.

Glyceraldehyde has one chiral center. b.

Dihydroxyacetone has two chiral centers. c.

d.

Mannose has four chiral centers

.

Tagatose has three chiral centers. Use your textbook to view these figures to help you. 4. Which of the following terms correctly describes the relationship between D-fructose and L fructose? Ans. = A a.

enantiomers b.

c.

d.

epimers diastereomers cis-trans isomers 5. Which of the following structures represents a β -monosaccharide? Ans. = B a.

c.

b.

d.

6. Which of the following monosaccharides has an open chain form that is a ketose? Ans. = D a.

c.

b.

d.

Testbank General, Organic, Biological Chemistry, 6 th edition 2

7. Which of the following structures is a representation of a cyclic form of D-glucose? Ans. = A a.

c.

b.

d.

8. In which of the following pairs or carbohydrates are both members of the pair disaccharides? Ans. = C a.

b.

allose and idose lactose and arabinose c.

d.

sucrose and maltose cellobiose and cellulose 9. Which of the following substances will produce both glucose and fructose when hydrolyzed? Ans. = C a.

lactose b.

c.

d.

maltose sucrose glycogen 10. The major structural difference between cellulose and starch is found in the: Ans. = C a.

identity of the monosaccharide units present b.

c.

d.

ring size of the monosaccharide units present linkages between the monosaccharide units present handedness of the monosaccharide units present 11. In which of the following polysaccharides are all glycosidic linkages of the beta (1 → 4) type? Ans. = B a.

starch b.

c.

d.

cellulose glycogen amylopectin Testbank General, Organic, Biological Chemistry, 6 th edition 3

12. Which of the following monosaccharides has a structure in which two or more chiral centers are present? Ans. = C a. glyceraldehyde b. dihydroxyacetone c. glucose d. more than one correct response e. no correct response 13. In which of the following disaccharides is a β (1 → 4) glycosidic linkage present? Ans. = A a.

lactose b.

sucrose c.

d.

e.

maltose more than one correct response no correct response 14. In which of the following pairs of carbohydrates are both members of the pair polysaccharides? Ans. = B a. cellulose and cellobiose b. starch and glycogen c. amylose and lactose d. more than one correct response e. no correct response

NUMERIC RESPONSE

Use the following to answer the questions below: For each of the compound characterizations, select from the response list an appropriate structural formula. Responses may be used more than once or need not be used at all. 15. An achiral compound. Ans. = B 16. A chiral compound with one chiral center. Ans. = A 17. A chiral compound with two chiral centers. Ans. = D Testbank General, Organic, Biological Chemistry, 6 th edition 4

18. Eight stereoisomers exist for this compound. Ans. = C 19. Four different L-stereoisomers exist for this compound. Ans. = C Use the following to answer the questions below: For each of the stereochemical descriptions, select from the response list an appropriate set of structural formulas. Responses may be used more than once or need not be used at all. 20. Enantiomers. Ans. = A 21. Mirror images. Ans. = A 22. Diastereomers. Ans. = B 23. Epimers. Ans. = B Testbank General, Organic, Biological Chemistry, 6 th edition 5

Use the following to answer the questions below: For each of the disaccharides or polysaccharides, select from the response list the correct hydrolysis (digestive) products. Responses may be used more than once or need not be used at all. a) glucose only b) glucose and galactose c) glucose and fructose d) glucose and ribose 24. Sucrose. Ans. = C 25. Lactose. Ans. = B 26. Cellulose. Ans. = A 27. Starch. Ans. = A 28. Glycogen. Ans. = A Use the following to answer the questions below: For each of the disaccharides or polysaccharides, select from the response list the correct characterization of the type of glycosidic linkages present in the compound. Responses may be used more than once or need not be used at all. a) α (1 → 4) only b) β (1 → 4) only c) α (1 → 4) and α (1 → 6) 29. Lactose. Ans. = B 30. Cellulose. Ans. = B 31. Amylopectin. Ans. = C 32. Chitin. Ans. = B Testbank General, Organic, Biological Chemistry, 6 th edition 6

Use the following to answer the questions below: For each of the compound characterizations, select an appropriate structural formula from the response list. Responses may be used more than once or need not be used at all. 33. D-glucose. Ans. = A 34. A beta monosaccharide. Ans. = A 35. A glycoside = Ans. = B 36. Open-chain form is an aldopentose. Ans. = C 37. Open-chain form is a ketohexose. Ans. = D Testbank General, Organic, Biological Chemistry, 6 th edition 7

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