Deck 11: Carbohydrates

Question 1

The molecular formula for a monosaccharide is _____ where _____.

A) C_nH_2n+2O_n; n 3
B) C_nH_2nO_n; n $\ge$ 3
C) C_nH_2nO_n; n $\ge$ 4
D) C_nH_2n+2O_n; n 11ee7c14_ba99_ddd9_ae82_1d1d27170a0b_TBW1044_11 4
E) none of the above

Answer 1

C_nH_2nO_n; n $\ge$ 3

Question 2

The three-carbon monosaccharide _____ is a(n) _____.

A) dihydroxyacetone; enantiomer
B) fructose; triose
C) ribose; hemiacetal
D) galactose; ketose
E) glyceraldehyde; aldose

Answer 2

glyceraldehyde; aldose

Question 3

What is the only monosaccharide that is achiral?

A) glyceraldehyde
B) ribose
C) galactose
D) dihydroxyacetone
E) fructose

Answer 3

dihydroxyacetone

Question 4

Which of the following best describes the relationship between the following molecules?

A) epimers
B) anomers
C) diastereomers
D) pentoses
E) one is a D sugar, one is an L sugar

Question 5

Which monosaccharide(s) seen below is(are) the enantiomer(s) of A?

A) B
B) C
C) D
D) B and C
E) C and D

Question 6

Which two monosaccharides seen below are epimers?

A) A and B
B) A and C
C) B and C
D) C and D
E) B and D

Question 7

Which of the following Haworth projections correctly shows the $\alpha$ anomer of galactose?

A)

B)

C)

D)

E) none of the above

Question 8

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

A) consists of approximately equal amounts of the $\alpha$ - and $\beta$ -anomers
B) the $\alpha$ -anomer is more stable and is slightly preferred over the $\beta$ -anomer
C) the $\beta$ -anomer predominates over the $\alpha$ -anomer by a ratio of approximately 2:1
D) straight-chain form is present in high concentration
E) none of the above

Question 9

The reaction between an alcohol and an anomeric carbon of a carbohydrate forms a _____ bond.

A) anomeric
B) glycosidic
C) hemiacetal
D) ester
E) ether

Question 10

Which of the following is glucose-6-phosphate?

A)

B)

C)

D)

E) none of the above

Question 11

Which of the following would be positively charged at physiological pH?

A) glucuronic acid
B) fructose-6-phosphate
C) xylitol
D) glucosamine
E) all of the above

Question 12

The following is a(n) _____ disaccharide with a(n) _____ glycosidic bond.

A) $\alpha$ ; $\beta$ (1 $\rarr$ 4)
B) $\alpha$ ; $\beta$ (1 $\rarr$ 1)
C) $\beta$ ; $\alpha$ (1 $\rarr$ 4)
D) $\beta$ ; $\alpha$ (1 $\rarr$ 1)
E) $\beta$ ; $\beta$ (1 $\rarr$ 4)

Question 13

Lactase, the enzyme responsible for breaking lactose into its monomers, is a(n) _____ enzyme.

A) $\beta$ -galactosidase
B) $\alpha$ -amylase
C) $\alpha$ -glycosidase
D) $\beta$ -glycosyltransferase
E) none of the above

Question 14

Amylopectin contains primarily _____ glycosidic bonds with _____ glycosidic bonds as branch points.

A) $\alpha$ (1 $\rarr$ 4); $\alpha$ (1 $\rarr$ 2)
B) $\alpha$ (1 $\rarr$ 4); $\alpha$ (1 $\rarr$ 6)
C) $\alpha$ (1 $\rarr$ 4); $\beta$ (1 $\rarr$ 6)
D) $\beta$ (1 $\rarr$ 4); $\alpha$ (1 $\rarr$ )
E) $\beta$ (1 $\rarr$ 4); $\alpha$ (1 $\rarr$ 6)

Question 15

The enzyme _____ from _____ allows animals such as cows to derive energy from cellulose.

A) chitinase; termites
B) cellulase; microorganisms
C) glucosyltransferase; viruses
D) lactase; microorganisms
E) none of the above

Question 16

Which of the following is a major difference between cellulose and chitin?

A) chitin is produced by insects, cellulose is produced by plants
B) chitin contains glucose and glucosamine, cellulose contains only glucose
C) chitin contains $\beta$ (1 $\rarr$ 6) glycosidic bonds, cellulose contains $\beta$ (1 $\rarr$ 4) glycosidic bonds
D) chitin is a branched polymer, cellulose is linear
E) none of the above

Question 17

Processing of N-glycosylated proteins within the Golgi apparatus involves the removal of monosaccharides by _____ and addition of new monosaccharides by _____.

A) glycosidases; glycosyltransferases
B) epimerases; glycosidases
C) cellulases; lactases
D) glycosyltransferases; N-amidases
E) proteases; glycosylases

Question 18

What glycosidic bonds are seen in the following portion of an N-linked oligosaccharide? Abbreviations: galactose: Gal; glucose: Glu; N-acetylglucosamine: NAG

A) F $\alpha$ (1 $\rarr$ 4) between Gal and NAG; $\beta$ (1 $\rarr$ 6) between Glu and NAG
B) $\beta$ (1 $\rarr$ 4) between Gal and NAG; $\alpha$ (1 $\rarr$ 3) between Glu and NAG
C) $\beta$ (1 $\rarr$ 3) between Gal and NAG; $\alpha$ (1 $\rarr$ 4) between Glu and NAG
D) $\alpha$ (1 $\rarr$ 4) between Gal and NAG; $\beta$ (1 $\rarr$ 3) between Glu and NAG
E) $\beta$ (1 $\rarr$ 4) between Gal and NAG; $\beta$ (1 $\rarr$ 3) between Glu and NAG

Question 19

Chondroitin sulfate, shown below, contains which of the following?

A) a $\beta$ (1 $\rarr$ 3) glycosidic bond
B) a $\beta$ (1 $\rarr$ 4) glycosidic bond
C) a glucuronic acid residue
D) a sulfate ester of N-acetylgalactosamine
E) all of the above

Question 20

Milk contains many oligosaccharides that cannot be digested by mammalian enzymes but instead are thought to serve as a source of nutriment for intestinal bacteria.

Question 21

In eukaryotes, intracellular proteins can be glycosylated by attachment of ___ to a ___ residue.

Question 22

The structure below shows a Fischer projection of D-Idose.
Which of the structures below represents $\beta$ -D-Idopyranose

A)

B)

C)

D)

E)