Question 1

Which of the following is true of glucitol?

Accepted Answer

A)  It exists only as an open-chain structure. 
B)  It exists only as a ring structure. 
C)  It exists as both ring and open-chain structures with the open-chain structure predominating. 
D)  It exists as both ring and open-chain structures with the ring structure predominating. 
A)  It exists only as an open-chain structure. 
B)  It exists only as a ring structure. 
C)  It exists as both ring and open-chain structures with the open-chain structure predominating. 
D)  It exists as both ring and open-chain structures with the ring structure predominating.

Question 2

Which of the following occurs when a monosaccharide is converted to an amino sugar?

Accepted Answer

A)  An amino group replaces an aldehyde carbonyl. 
B)  An amino group replaces a ketone carbonyl. 
C)  An amino group replaces a hydroxyl group. 
D)  Any of the above, it depends on the identity of the monosaccharide. 
A)  An amino group replaces an aldehyde carbonyl. 
B)  An amino group replaces a ketone carbonyl. 
C)  An amino group replaces a hydroxyl group. 
D)  Any of the above, it depends on the identity of the monosaccharide.

Question 3

Approximately what percentage of plant starch is amylopectin?

Accepted Answer

A)  10 to 15% 
B)  20 to 25% 
C)  75 to 80% 
D)  85 to 90% 
A)  10 to 15% 
B)  20 to 25% 
C)  75 to 80% 
D)  85 to 90%

Question 4

How many different D-2-ketohexoses are there?

Accepted Answer

A)  2 
B)  4 
C)  8 
D)  16 
A)  2 
B)  4 
C)  8 
D)  16

Question 5

Under which of the following conditions can monosaccharides be oxidized to uronic acids?

Accepted Answer

A)  basic 
B)  enzymatic 
C)  acidic 
D)  none of these 
A)  basic 
B)  enzymatic 
C)  acidic 
D)  none of these

Question 6

Where is glycogen stored?

Accepted Answer

A)  only in the liver 
B)  only in the muscles 
C)  in both liver and muscles, but largely in the liver 
D)  in both the liver and muscles with approximately equal amounts in both 
A)  only in the liver 
B)  only in the muscles 
C)  in both liver and muscles, but largely in the liver 
D)  in both the liver and muscles with approximately equal amounts in both

Question 7

Including pairs of enantiomers, how many different 2-ketopentoses are there?

Accepted Answer

A)  2 
B)  4 
C)  8 
D)  16 
A)  2 
B)  4 
C)  8 
D)  16

Question 8

Which are the most abundant organic compounds in the plant world?

Accepted Answer

A)  alcohols 
B)  amino acids 
C)  carbohydrates 
D)  proteins 
A)  alcohols 
B)  amino acids 
C)  carbohydrates 
D)  proteins

Question 9

Carbohydrates account for approximately what percentage of the body weight of animals?

Accepted Answer

A)  1% 
B)  5% 
C)  10% 
D)  15% 
A)  1% 
B)  5% 
C)  10% 
D)  15%

Question 10

Which of the following is true of the spatial distribution of the hydroxyl groups of β-D-glucopyranose?

Accepted Answer

A)  They are all in axial positions. 
B)  They are all in equatorial positions. 
C)  The hydroxyl on C-1 is axial, those on C-2, C-3 and C-4 are equatorial. 
D)  The hydroxyl on C-1 is equatorial, those on C-2, C-3 and C-4 are axial. 
A)  They are all in axial positions. 
B)  They are all in equatorial positions. 
C)  The hydroxyl on C-1 is axial, those on C-2, C-3 and C-4 are equatorial. 
D)  The hydroxyl on C-1 is equatorial, those on C-2, C-3 and C-4 are axial.

Question 11

Which of the following is true of glucose 6-phosphate?

Accepted Answer

A)  It is a cationic species with a charge of +1. 
B)  It is an electrically neutral molecule. 
C)  It is an anionic species with a charge of −1. 
D)  It is an anionic species with a charge of −2. 
A)  It is a cationic species with a charge of +1. 
B)  It is an electrically neutral molecule. 
C)  It is an anionic species with a charge of −1. 
D)  It is an anionic species with a charge of −2.

Question 12

The configuration at which carbon of a pentose determines if the pentose has the D or L configuration?

Accepted Answer

A)  C-1 
B)  C-3 
C)  C-4 
D)  C-5 
A)  C-1 
B)  C-3 
C)  C-4 
D)  C-5

Question 13

How many chiral carbons are present in the open-chain form of an aldohexose?

Accepted Answer

A)  3 
B)  4 
C)  5 
D)  6 
A)  3 
B)  4 
C)  5 
D)  6

Question 14

In the test for blood glucose which of the following is formed?

Accepted Answer

A)  D-glucitol 
B)  D-gluconic acid 
C)  D-glucuronic acid 
D)  methyl-α-D-glucopyranoside 
A)  D-glucitol 
B)  D-gluconic acid 
C)  D-glucuronic acid 
D)  methyl-α-D-glucopyranoside

Question 15

Which carbon is the site of reaction when glucose reacts to form a glucoside?

Accepted Answer

A)  C-1 
B)  C-2 
C)  C-5 
D)  C-6 
A)  C-1 
B)  C-2 
C)  C-5 
D)  C-6

Question 16

The D-form of which of the following amino sugars is not commonly found naturally?

Accepted Answer

A)  galactosamine 
B)  glucosamine 
C)  mannosamine 
D)  ribosamine 
A)  galactosamine 
B)  glucosamine 
C)  mannosamine 
D)  ribosamine

Question 17

How many amino sugars are common in nature?

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4 
A)  1 
B)  2 
C)  3 
D)  4

Question 18

How many chiral carbons are present in the open-chain form of a ketopentose?

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4 
A)  1 
B)  2 
C)  3 
D)  4

Question 19

What is the relationship between the number of stereocenters in a monosaccharide in its open-chain and ring structures?

Accepted Answer

A)  The two structures contain the same number of stereocenters. 
B)  The open-chain form contains one less stereocenter than does the ring. 
C)  The open-chain form contains one more stereocenter than does the ring. 
D)  There is no general relationship, each case must be considered separately. 
A)  The two structures contain the same number of stereocenters. 
B)  The open-chain form contains one less stereocenter than does the ring. 
C)  The open-chain form contains one more stereocenter than does the ring. 
D)  There is no general relationship, each case must be considered separately.

Question 20

Approximately what percentage of plant starch is amylose?

Accepted Answer

A)  10 to 15% 
B)  20 to 25% 
C)  75 to 80% 
D)  85 to 90% 
A)  10 to 15% 
B)  20 to 25% 
C)  75 to 80% 
D)  85 to 90%

Exam 20: Carbohydrates

Which of the following is true of glucitol?

Which of the following occurs when a monosaccharide is converted to an amino sugar?

Approximately what percentage of plant starch is amylopectin?

How many different D-2-ketohexoses are there?

Under which of the following conditions can monosaccharides be oxidized to uronic acids?

Where is glycogen stored?

Including pairs of enantiomers, how many different 2-ketopentoses are there?

Which are the most abundant organic compounds in the plant world?

Carbohydrates account for approximately what percentage of the body weight of animals?

Which of the following is true of the spatial distribution of the hydroxyl groups of β-D-glucopyranose?

Which of the following is true of glucose 6-phosphate?

The configuration at which carbon of a pentose determines if the pentose has the D or L configuration?

How many chiral carbons are present in the open-chain form of an aldohexose?

In the test for blood glucose which of the following is formed?

Which carbon is the site of reaction when glucose reacts to form a glucoside?

The D-form of which of the following amino sugars is not commonly found naturally?

How many amino sugars are common in nature?

How many chiral carbons are present in the open-chain form of a ketopentose?

What is the relationship between the number of stereocenters in a monosaccharide in its open-chain and ring structures?

Approximately what percentage of plant starch is amylose?

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