Deck 9: Carbohydrates: Sugars, Saccharides, Glycans

Question 1

Which of the following would be an anomer of $\alpha$ -D-galactopyranose?

A)
B)
C)
D)
E)None of the above

Answer 1

Question 2

Lactose, the disaccharide of galactose and glucose, is synthesized from which of the following activated monosaccharides?

A)uridine triphosphate glucose
B)uridine triphosphate galactose
C)uridine diphosphate glucose
D)uridine diphosphate galactose
E)none of the above

Answer 2

D

Question 3

Which of the following correctly identifies key elements present on the exterior of Gram-negative (GN)and Gram-positive (GP)bacteria?

A)GN: single lipid bilayer; GP: two lipid bilayers
B)GN: single peptidoglycan layer; GP: multiple peptidoglycan layers
C)GN: extensively crosslinked peptidoglycans; GP: uncrosslinked peptidoglycan
D)GN: contains both N-acetylmuramic acid and N-acetylglucosamine; GP: contains only N-acetylmuramic acid
E)none of the above

Answer 3

B

Question 4

Of the following phosphate esters of monosaccharides, which has the most spontaneous $\Delta$ G ^$\circ$ ´ of hydrolysis?

A) $\alpha$ -D-glucose-6-phosphate
B) $\beta$ -D-glucose-6-phosphate
C) $\beta$ -D-glucose-1-phosphate
D) $\alpha$ -D-fructose-6-phosphate
E)D-glyceraldehyde-3-phosphate

Question 5

The two most common amino sugars, $\beta$ -D-glucosamine and $\beta$ -D-galactosamine are formed from their respective carbohydrates by substitution of an amine group for the hydroxyl on carbon _____.

A)2
B)3
C)4
D)5
E)6

Question 6

Which of the following designations best characterizes the following disaccharide?

A)Glc $\alpha$ (1 $\rarr$ 4)Gal
B)Glc $\beta$ (1 $\rarr$ 4)Gal
C)Gal $\alpha$ (1 $\rarr$ 4)Gal
D)Gal $\beta$ (1 $\rarr$ 4)Gal
E)none of the above

Question 7

How many carbon atoms are found in the smallest molecules that are classified as carbohydrates?

A)1
B)2
C)3
D)4
E)5

Question 8

Which of the following is a ketose?

A)
B)
C)
D)
E)None of the above

Question 9

Dihydroxyacetone is classified as a(n)_______.

A)aldotriose
B)ketotriose
C)aldotetrose
D)ketotetrose
E)none of the above

Question 10

Which of the following explains the importance of sucrose as a disaccharide?

A)the glycosidic bond is much more stable than a typical glycosidic bond
B)the presence of two glucose residues provides a readily available glucose source
C) $\beta$ -glycosidic bonds are much more stable than $\alpha$ -glycosidic bonds
D)since both anomeric carbons are involved in the glycosidic bond, oxidation is limited
E)none of the above

Question 11

Which of the following is a diastereomer of D-mannose?

A)D-gulose
B)D-altrose
C)D-idose
D)D-talose
E)all of the above

Question 12

Which of the following polysaccharides contains exclusively glucose in $\beta$ (1 $\rarr$ 4)glycosidic bonds?

A)amylose
B)amylopectin
C)glycogen
D)cellulose
E)chitin

Question 13

Which of the following formulas would be a carbohydrate

A)C₅H₁₂O₅
B)C₄H₈O₆
C)C₆H₁₀O₆
D)C₃H₈O₃
E)C₆H₁₂O₆

Question 14

Which of the following would be the correct Haworth projection for $\alpha$ -D-gulose, whose linear form is seen below?

A)
B)
C)
D)
E)None of the above

Question 15

The role of collagen in vertebrate bones as a matrix for mineral deposition is most analogous to the role of _________ in ___________.

A)cellulose; plant cell walls
B)chitin; invertebrate exoskeletons
C)xylan; plant cell walls
D)keratan sulfate: mammalian skin
E)amylose: plant cell walls

Question 16

How many stereoisomers would be expected from a ketohexose?

A)4
B)8
C)16
D)32
E)64

Question 17

Gluconic acid is derived from ________ while glucuronic acid is derived from _______.

A)glucose; gulose
B)gulose; glucose
C)glucose; glucose
D)glucose; galactose
E)galactose; glucose

Question 18

All glycosaminoglycans contain which of the following?

A)a sulfate ester
B)a $\beta$ (1 $\rarr$ 4)glycosidic bond
C)a carboxylate
D)an amine group that is either acetylated or sulfated
E)all of the above

Question 19

The reaction of a cyclic monosaccharide with an alcohol converts a(n)_________ into a(n)________.

A)acetal; hemiacetal
B)hemiacetal; acetal
C)acetal; ether
D)hemiacetal; ether
E)alcohol; ether

Question 20

What is the C-4 epimer of glucose?

A)allose
B)mannose
C)gulose
D)galactose
E)fructose

Question 21

Draw a $\beta$ -disaccharide composed of glucose linked to its C-2 epimer by an $\alpha$ (1 $\rarr$ 4)glycosidic bond with the anomeric carbon of glucose contributing to the glycosidic bond.

Question 22

An N-linked glycan would be attached to ______ while an O-linked glycan would be attached to ________.

A)Asn; Ser
B)Lys; Tyr
C)Gln; Thr
D)Arg; Ser
E)Lys; Ser

Question 23

Show the interaction that would take place between the R-group of asparagine in a protein and the substituent on C-2 of an N-acetylglucosamine residue of a glycan.

Question 24

Using the structure of D-altrose, shown below, show a Haworth projection for the $\beta$ anomer.

Question 25

Antibiotic inhibition of cell wall synthesis can be facilitated by a number of agents. The crosslinking of peptidoglycan strands is inhibited by _________ while polymerization of the growing peptidoglycan is inhibited by __________.

A)penicillin; bacitracin
B)penicillin; vancomycin
C)vancomycin; bacitracin
D)vancomycin; penicillin
E)bacitracin; vancomycin

Question 26

Given the structure of D-galactose, draw the structure of L-galactose in both open chain and Haworth projections ( $\alpha$ anomer).

Question 27

The source of nitrogen for the synthesis of glucosamine-6-phosphate from fructose-6-phosphate is the amino acid ___________.

A)aspartate
B)asparagine
C)glutamate
D)glutamine
E)lysine

Question 28

Oseltamivir, also known as Tamiflu, is effective as an antiviral against the influenza virus due to its ability to block the action of which protein associated with the surface of the viral particle?

A)hemagglutinin
B)neuraminidase
C)M1
D)M2
E)none of the above