Deck 24: Carbohydrates: Polyfunctional Compounds in Nature

Question 1

What would result from the reactions shown below?

A)

B)

C)

D)

E)

Answer 1

Question 2

D-(+)-Glucose and D-(+)-Mannose have the same molecular formula (C₆H₁₂O₆).Which of the following describes the relationship between these two sugars?

A) Constitutional isomers
B) Diastereomers
C) Enantiomers
D) Anomers
E) no correct answer

Answer 2

Diastereomers

Question 3

What would result from the following series of reactions?

A)

B)

C)

D)

E) both A and C

Answer 3

both A and C

Question 4

The chair conformation for $\alpha$ -D-Glucopyranose (shown below)may also be correctly represented by which of the following Haworth projections?

A)

B)

C)

D)

E)

Question 5

What would be the name of the following sugar structure?

A) ( $\alpha$ -D-galactopyranose)
B) ( $\beta$ -D-glucopyranose)
C) ( $\beta$ -D-galactopyranose)
D) ( $\alpha$ -D-glucopyranose)
E) ( $\beta$ -D-galactofuranose)

Question 6

The term "epimer" is best defined as:

A) Molecules which are enantiomers of each other
B) Meso compounds
C) Any pair of diastereomers
D) Two diastereomers that differ in configuration at only one stereocenter
E) Racemic mixture

Question 7

Which one of the following could not rotate plane polarized light?

A)

B)

C)

D)

E)

Question 8

Which disaccharide possesses a 1,1' linkage?

A) Cellobiose
B) Maltose
C) Lactose
D) Sucrose
E) Glucose

Question 9

Which of the following would be a reducing sugar (i.e.,react with Ag+)?

A)

B)

C)

D)

E)

Question 10

Predict the major product of the following reaction.

A)

B)

C)

D)

E)

Question 11

What would result from the reaction shown below?

A)

B)

C)

D)

E)

Question 12

What would be the name of the following sugar?

A) ( $\beta$ -D-glucopyranose)
B) ( $\alpha$ -D-galactopyranose)
C) ( $\alpha$ -D-glucopyranose)
D) ( $\beta$ -D-galactopyranose)
E) ( $\beta$ -D-glucofuranose)

Question 13

What would be the name of the following sugar?

A) D-glucose
B) L-glucose
C) L-galactose
D) L-mannose
E) D-mannose

Question 14

Which of the following would you expect to exhibit mutarotation?

A)

B)

C)

D)

E)

Question 15

Qualitatively (not quantitatively),what products would be formed from the following reaction?

A) CO₂
B) CH₂O
C)

D) both B and C
E) A,B and C

Question 16

Which of the following is referred to as the anomeric carbon?

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

Question 17

The main difference between the two forms of starch,amylose and amylopectin,is what?

A) Amylose is more soluble in water than is amylopectin.
B) Amylose is a linear polymer while amylopectin is branched.
C) Amylopectin has a lower molecular weight than amylose.
D) Amylose is metabolized in mammals,while amylopectin is not.
E) Amylopectin is metabolized in mammals,while amylose is not.

Question 18

Which compound would result from the following reaction?

A)

B)

C)

D)

E)

Question 19

Bromine is a dense,deep red-brown liquid obtained by the oxidation of bromide ion in seawater.Bromine is very toxic.Which of the following reactions of bromine with organic materials would be least likely in a biological system (would not occur)?

A) Addition to non-aromatic carbon-carbon double bonds (e.g.,in fatty acids)
B) Electrophillic aromatic substitution of very activated aromatic rings (e.g.,in tyrosine,a phenol)
C) Oxidation of aldoses to aldonic acids (e.g.,CHO to CO₂
D) ( $\alpha$ -bromination of fatty acids (e.g.,RCH₂CO₂H $\rightarrow$ RCHBrCO₂H))
E) None of these reactions could occur in living systems.

Question 20

In which of the following is a typical (most common)disaccharide linkage present (i.e.,in what way does nature link most di- and poly-saccharides: 1,1' vs 1,2' vs 1,3' vs 1,4' vs 1,6')?

A)

B)

C)

D)

E)

Question 21

Periodic acid degradation of the following carbohydrate will yield (quantitatively)what products?

A) 4 HCO₂H + 1 CO₂
B) 3 HCO₂H + 1 HCHO + 1 CO₂
C) 4 HCO₂H + 1 HCHO
D) 5 HCHO
E) 4 HCHO + 1 CO₂

Question 22

Which of the following arrows correctly points to the anomeric carbon?

A) Arrow A
B) Arrow B
C) Arrow C
D) Arrow D
E) Arrow E

Question 23

The carbohydrate structures below are related as

A) Anomers
B) Enantiomers
C) Diastereomers
D) D and L stereoisomers
E) both B and D

Question 24

Which of the following conformations correctly depicts the structure of: $\alpha$ -D-(+)-Glucopyranose?

A)

B)

C)

D)

E)

Question 25

Which of the following "dash-wedge" (zig-zag)structures correctly depicts D-Glucose?

A)

B)

C)

D)

E)

Question 26

Which polysaccharide has $\beta$ -1,4 glycosidic bonds?

A) Cellulose
B) Glycogen
C) Amylose
D) Amylpectin
E) B,C,and D

Question 27

Which of the following represents an L sugar?

A)

B)

C)

D)

E)