Deck 20: The Organic Chemistry of Carbohydrates

Question 1

Which of the following terms best describes an aldohexose?
1) A monosaccharide
2) A disaccharide
3) An aldehyde
4) A complex carbohydrate

A) 1 and 3
B) 2 and 3
C) 2 and 4
D) 1, 3, and 4
E) 2, 3, and 4

Answer 1

1 and 3

Question 2

D and L notations used in describing the stereochemistry of carbohydrates ____________.

A) are directly related to the R and S notation.
B) are directly related to the (+) and (?) notation.
C) are used to describe the asymmetric carbon farthest from the carbonyl group
D) are directly related to how the molecule rotates plane-polarized light
E) are used to describe the uppermost asymmetric carbon atom

Answer 2

are used to describe the asymmetric carbon farthest from the carbonyl group

Question 3

Which of the following carbohydrates is D-glucose?

A)
B)
C)
D)
E)

Answer 3

Question 4

How many stereoisomeric D-2-ketohexoses are possible?

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

Question 5

Which reagent(s) will selectively react with aldoses but will not react with ketoses?

A) Br₂/H₂O
B) Ag⁺, NH₃, HO^?
C) HNO₃
D) A and B
E) B and C

Question 6

The Kiliani-Fischer synthesis (below) gives which two C-2 epimers?

A) allose/altrose
B) gulose/idose
C) glucose/mannose
D) galactose/talose
E) sucrose/fructose

Question 7

Which of the following D-hexoses can be converted to D-ribose by a Wohl degradation?

A) D-allose
B) D-glucose
C) D-galactose
D) D-talose
E) C and D

Question 8

Which of the following Haworth projections is ?-D-glucose?

A)
B)
C)
D)
E)

Question 9

Which D-aldohexose in its beta-D-pyranose form has only one OH group in the axial position?

A)D-allose
B) D-galactose
C)D-gulose
D)D-iodose
E)D-talose

Question 10

Which of the following is a reducing sugar?

A)
B)
C)
D)
E) all of the above

Question 11

D-Glucose units joined by beta-1,4?-glycosidic linkages are not digestible by humans because____________.

A) humans lack the enzyme necessary to hydrolyze this linkage
B) all groups being equatorial in the glucose rings make the chains too stable to digest
C) it is a glycoside and, therefore, indigestible
D) it is unbranched and, therefore, indigestible
E) all the above