Verified Test Bank Chapter 20 Carbohydrates

General, Organic and Biological Chemistry, 4e (Smith)

Chapter 20 Carbohydrates

1) Which carbohydrates cannot be converted to simpler compounds by hydrolysis?

A) Disaccharides

B) Monosaccharides

C) Polysaccharides

D) Starches

2) What are monosaccharides with a carbonyl group at C1 called?

A) Anomers

B) Aldoses

C) Ketoses

D) Alditols

3) What is the classification of the compound shown below?

A) An aldohexose

B) A ketohexose

C) An aldopentose

D) A ketopentose

4) What is the classification of the compound shown below?

A) A tetraketose

B) A ketotriose

C) A ketotetrose

D) An aldotriose

5) What is the classification of the compound shown below?

A) Aldohexose

B) Aldopentose

C) Ketotetrose

D) Ketopentose

6) Which of the following is a ketohexose?

A)

B)

C)

D)

7) Which monosaccharide is an aldotriose?

A)

B)

C)

D)

8) Which compound is the most soluble in water?

A) CH2OHCHOHCHOHCHOHCHOHCHO

B) CH3CH2CH=CHCH2CH=CHCH2CH2CH2CH2CH2CH2CH2COOH

C) CH3CH2CH2CH2CH2CH2CH2CH2CH3

D) CH3CH2CH2CH2CH2CH2CH2CH2OH

9) What is the classification of the compound shown below?

A) L

B) D

C) A sugar this small is not classified as L or D.

10) How many chirality centers are present in the compound shown below?

A) 2

B) 4

C) 5

D) 6

11) How many chirality centers are present in the compound shown below?

A) 1

B) 2

C) 3

D) 4

12) In the monosaccharide given, which of the labeled carbons are chiral centers?

A) C1 is the only chiral center.

B) C1 and C2 are both chiral centers.

C) C2 and C3 are both chiral centers

D) C3 is the only chiral center

13) What is the classification of the monosaccharide shown?

A) L

B) D

C) A sugar this large is not classified as L or D.

14) The structures of galactose (left) and glucose (right) are shown below. How are the two monosaccharides related?

A) Structural isomers

B) Stereoisomers

C) Enantiomers

D) Anomers

15) When converting a Fischer projection to a Haworth projection, where are all of the substituents on the right side of the carbon skeleton drawn in the Haworth projection?

A) Down

B) Up

C) Down in an α anomer and up in a β anomer

D) Down in an β anomer and up in a α anomer

16) Which Haworth projection represents the banomer of the monosaccharide shown below?

A)

B)

C)

D)

17) Which Haworth projection represents the α anomer of the monosaccharide shown below?

A)

B)

C)

D)

18) Which labeled carbon atom in the structure below is the anomeric carbon?

A) A

B) B

C) C

D) D

19) What product forms when the compound below is treated with H2 in the presence of a Pd catalyst?

A)

B)

C)

D)

20) The formation of what color in the Benedict's test indicates a reducing sugar is present in solution?

A) Blue

B) Brick red

C) Bright yellow

D) Silver

21) What product forms when the compound below is treated with Benedict's reagent?

A)

B)

C)

D)

22) What product forms when the compound below is treated with Benedict's reagent?

A)

B)

C)

D)

E) No reaction occurs.

23) Disaccharides and polysaccharides contain monosaccharide units joined together by which of the following?

A) Hydrogen bonding

B) Glycosidic linkages

C) Hemiacetal bonds

D) Dipole-dipole forces

24) Lactose is present in milk. What type of sugar is lactose?

A) A disaccharide

B) A monosaccharide

C) A polysaccharide

D) A starch

25) How many acetals are present in the disaccharide shown below?

A) 1

B) 2

C) 3

D) 4

26) How many acetals and hemiacetals are present in the disaccharide below?

A) Two acetals are present.

B) Two hemiacetals are present.

C) One hemiacetal and one acetal is present

D) No hemiacetals or acetals are present.

27) Which choice properly describes the glycoside bond in the disaccharide below?

A) 1→6-α

B) 1→6-β

C) 1→4α

D) 1→4β

28) Salicin is a naturally occurring, carbohydrate-containing pain reliever. Which statement concerning the functional groups present in salicin is incorrect?

A) Salicin contains an acetal.

B) Salicin contains an alcohol.

C) Salicin contains a hemiacetal.

D) Salicin contains a phenol.

29) Which is the only polysaccharide to have β-glycosidic bonds?

A) Glycogen

B) Amylose

C) Cellulose

D) Amylopectin

30) Which is not a naturally-occurring polysaccharide?

A) Starch

B) Cellulose

C) Maltose

D) Glycogen

31) Why are humans not able to digest cellulose?

A) Humans cannot digest glucose.

B) Humans do not possess the enzyme necessary to hydrolyze the 1→4-β-glycoside linkages found in cellulose.

C) Humans do not possess the enzyme necessary to unwind the helical shape of the cellulose molecule.

D) Humans do not possess the enzyme necessary to hydrolyze the 1→4-α-glycoside linkages found in cellulose.

32) What is the structure of amylopectin?

A) Unbranched skeleton of glucose molecules joined by 1→4-α-glycoside linkages

B) Branched skeleton of glucose molecules joined by 1→4-α-glycoside linkages

C) Unbranched skeleton of glucose molecules joined by 1→4-β-glycoside linkages

D) Branched skeleton of glucose molecules joined by 1→4-β-glycoside linkages

33) What is the structure of cellulose?

A) Unbranched skeleton of glucose molecules joined by 1→4-α-glycoside linkages

B) Branched skeleton of glucose molecules joined by 1→4-α-glycoside linkages

C) Unbranched skeleton of glucose molecules joined by 1→4-β-glycoside linkages

D) Branched skeleton of glucose molecules joined by 1→4-β-glycoside linkages

34) What is the most common type of starch molecules?

A) Cellulose

B) Amylose

C) Amylopectin

D) Glycogen

35) What is the polysaccharide form in which glucose is stored in animals?

A) Cellulose

B) Amylose

C) Amylopectin

D) Glycogen

36) Which is not a glycosaminoglycan?

A) Hyaluronate

B) Chitin

C) Heparin

D) Chondroitin

37) Chitin is identical in structure to cellulose, except that

A) The linkages are a-glycoside linkages.

B) Each OH group at C4 is replaced by NHCOCH3.

C) Each OH group at C2 is replaced by NH3.

D) Each OH group at C2 is replaced by NHCOCH3.

38) What monosaccharide is found in cellulose, starch, and glycogen?

A) Glucose

B) Galactose

C) Sucrose

D) Fructose

39) Which carbohydrate derivative forms a gel-like matrix in joints and the vitreous humor of the eye?

A) Heparin

B) Chondroitin

C) Hyaluronate

D) Chitin

40) What is responsible for the different blood types in humans?

A) Three or four proteins attached to a membrane monosaccharide on the surface of red blood cells

B) Three or four monosaccharides attached to a membrane protein on the surface of red blood cells

C) Three or four amino acids attached to a membrane monosaccharide on the surface of red blood cells

D) Three or four lipids attached to a membrane polysaccharide on the surface of red blood cells

41) Which structure is a three-carbon alditol?

A)

B)

C)

D)

42) Which is not a reducing sugar?

A) Glucose

B) Fructose

C) Sucrose

D) Galactose

E) An aldopentose

43) Which naturally-occurring monosaccharide forms the Haworth structure shown?

A)

B)

C)

D)

44) What type of polysaccharide is depicted in the "cartoon" shown below?

A) Cellulose

B) Amylose

C) Amylopectin

D) Chitin

45) What is the difference between the disaccharides lactose and maltose?

A) Lactose contains two glucose units, while maltose contains two galactose units.

B) The two monosaccharides in lactose are joined by a 1→4-β-glycoside bond, while the two monosaccharides in maltose are joined by a 1→4-α-glycoside bond.

C) Lactose contains both an acetal and a hemiacetal, while maltose contains two acetals.

D) Lactose can be hydrolyzed in the body, but maltose cannot.

46) The simplest aldose is commonly called glyceraldehyde, although its IUPAC name is 2,3-dihydroxypropanal. What is the structure of this compound?

A)

B)

C)

D)

47) The simplest aldose is commonly called dihydroxyacetone, although its IUPAC name is 1,3-dihydroxy-2-propanone.  What is the structure of this compound?

A)

B)

C)

D)

48) Dihydroxyacetone, shown below, is the simplest ketose. Does the structure shown represent D-dihydroxyacetone or L-dihydroxyacetone?

A) D-dihydroxyacetone

B) L-dihydroxyacetone

C) Neither D nor L; dihydroxyacetone is not chiral

D) It is impossible to tell from the Fischer projection alone.

49) The Fischer projections of two monosaccharides are shown below. Which term best describes the relationship between the two?

A) Enantiomers

B) Anomers

C) Constitutional isomers

D) Diastereomers

50) Which of the following is not a term that would properly describe glucose as it is shown below?

A) Monosaccharide

B) Aldohexose

C) Reducing sugar

D) β-D-glucose

51) Melibiose is a carbohydrate found in some plant juices. Which statement concerning melibiose is incorrect?

A) It is a disaccharide.

B) It is composed of two different monosaccharides.

C) It contains both an acetal and a hemiacetal.

D) It contains a 1→5-α-glycosidic linkage.

52) Gentobiose, a rare disaccharide found in saffron, produces two identical monosaccharides when it undergoes hydrolysis. What is the identity of the hydrolysis product?

A)

B)

C)

D)

53) Which statement concerning carbohydrates is incorrect?

A) Carbohydrates serve important energy and structural roles for both plants and animals.

B) Monosaccharides are the simplest carbohydrates and are known as simple sugars.

C) Humans store excess glucose for short term energy requirements in the polysaccharide cellulose.

D) Carbohydrates that can be oxidized by Benedict's reagent are called reducing sugars.

54) When a monosaccharide forms a cyclic hemiacetal, the carbon atom that is part of the hemiacetal is a new chirality center, called the anomeric carbon.

55) The β anomer of a cyclic monosaccharide has the –OH group drawn down, below the ring.

56) A hemiacetal is a compound that contains a hydroxyl group (–OH) and an alkoxy group (–OR) on adjacent carbon atoms.

57) The monosaccharide shown below is an α anomer.

58) At equilibrium, a solution of glucose in water is an equal mixture of the α anomer, the β anomer, and the acyclic aldehyde.

59) Certain monosaccharides—notably aldopentoses and ketohexoses—form five-membered rings, not six-membered rings, in solution.

60) The monosaccharide shown below is an α anomer.

61) The carbonyl group of an aldose is reduced to a secondary alcohol using hydrogen (H2) in the presence of palladium (Pd) metal.

62) An alditol contains an –OH group on every carbon atom.

63) Carbohydrates that are oxidized with Benedict's reagent are called reducing sugars, because they reduce the Cu2+ in Benedict's reagent to Cu+ during the reaction.

64) All aldoses and ketoses are reducing sugars.

65) Test strips that contain the enzyme lactase are used to measure glucose concentration in urine.

66) Modern glucose meters are electronic devices that measure the amount of oxidizing agent that reacts with the glucose in a known amount of blood.

67) All disaccharides contain at least one acetal that joins the rings together.

68) An α glycoside has the glycosidic linkage oriented down, below the plane of the ring that contains the acetal joining the monosaccharides.

69) The disaccharide shown below has an α-glycosidic linkage.

70) Hydrolysis of the disaccharide below yields the indicated products.

71) Cellulose is a highly-branched polymer composed of repeating glucose units joined in a 1→4-β-glycosidic linkage.

72) In addition to the three monosaccharides that occur in all blood types, type A blood contains the monosaccharide N-acetyl-D-galactosamine, and type B blood contains an additional D-galactose unit.

73) Individuals with type AB blood are called universal recipients because their blood contains no antibodies to blood types A, B, or O. Individuals with type AB blood can receive blood of any type.

74) The two compounds N-acetyl-D-glucosamine and N-acetyl-D-galactosamine are a set of constitutional isomers.

75) In aldohexoses, it is the –OH group on C5 that reacts with the aldehyde carbonyl to form two cyclic hemiacetals called anomers.

76) α-D-galactose and β-D-galactose are enantiomers.

77) The structure shown has four (4) chirality centers and is a D monosaccharide.

78) Maltose is a reducing sugar.

79) Glucose and other naturally occurring sugars are D sugars.

80) When the monosaccharide below is oxidized by Benedict's reagent, the indicated product results.

81) In the disaccharide structure shown, the anomeric carbons are properly labeled.

82) The conversion of D-ribose to L-ribose is an example of mutarotation.

83) Carbohydrates serve important energy and structural roles for both plants and animals.

84) Carbohydrates are chiral biomolecules. The term chiral indicates that carbohydrates can be both synthesized and digested by the human body.

85) Carbohydrates are structurally defined as polyhydroxyaldehydes and polyhydroxyketones, or compounds that can be hydrolyzed to them.

86) Disaccharides contain two carbonyl groups.

87) Monosaccharides with a carbonyl group at C2 are called ketoses.

88) Monosaccharides are polar compounds with low melting points.

89) All carbohydrates, except for dihydroxyacetone, contain one or more chirality centers.

90) The naturally occurring enantiomer of a monosaccharide is distinguished by the prefix L-.

91) The two monosaccharides shown below are related as enantiomers.

92) ________ are the simplest carbohydrates.

93) The configuration of the chirality center ________ (closest to/farthest from) the carbonyl group determines whether a monosaccharide is D or L.

94) Dextrose is another name for the monosaccharide ________.

95) The product of the reduction of an aldose is called a/an ________, also referred to as a "sugar alcohol."

96) The hydrolysis of a disaccharide cleaves the ________ linkage and forms two monosaccharides.

97) Individuals who are lactose intolerant no longer produce the enzyme ________.

98) Sucrose is a disaccharide that contains one ________ unit and one ________ unit.

99) Humans store glucose for short term energy requirements in the polysaccharide ________.

100) Carbohydrates are synthesized in green plants and algae through ________, a process that uses the energy from the sun to convert carbon dioxide and water into ________ and oxygen.