Question 1

Which of the following statements best explains why sucrose is NOT a reducing sugar?

Accepted Answer

Because both anomeric carbons are involved in the glycosidic bond, leaving no free anomeric carbon.

Question 2

A patient with type 1 diabetes is unable to regulate blood glucose levels. Which carbohydrate is directly responsible for the elevated blood sugar in this condition?

Accepted Answer

Glucose

Question 3

Which of the following best describes the difference between D-ribose and 2-deoxyribose?

Accepted Answer

2-deoxyribose lacks an oxygen atom on carbon 2 compared to ribose.

Question 4

Which glycosidic bond is found in lactose, and why is lactose considered a reducing sugar?

Accepted Answer

It has a $$\beta(1 \rightarrow 4)$$ bond, and the glucose anomeric carbon is free.

Question 5

A carbohydrate with the formula $$C_5H_{10}O_5$ and an aldehyde group is classified as which of the following?

Accepted Answer

Aldopentose

Question 6

Which of the following statements about cellulose is correct?

Accepted Answer

It is composed of $$\beta(1 \rightarrow 4)$$ linked glucose units, forming straight, rigid fibers.

Question 7

How many stereoisomers are possible for a hexose monosaccharide with 4 chiral centers?

Accepted Answer

$$2^4 = 16$

Question 8

Which of the following best describes the role of heparin in the human body?

Accepted Answer

It is a polysaccharide that prevents blood clotting due to its highly ionic, sulfated structure.

Question 9

Which of the following statements about the Benedict’s test is correct?

Accepted Answer

It detects reducing sugars by the reduction of $$Cu^{2+} to$$ $$Cu^+$$, forming a brick-red precipitate.

Question 10

Which of the following best explains why glycogen can be rapidly mobilized to release glucose in animals?

Accepted Answer

It has many $$\alpha(1 \rightarrow 6)$$ branches, allowing multiple enzymes to hydrolyze glucose simultaneously.

Question 11

Which of the following is a correct statement about the Fischer projection of D-glucose?

Accepted Answer

The –OH group on the chiral carbon farthest from the carbonyl is on the right.

Question 12

Which of the following best describes the difference between an aldose and a ketose?

Accepted Answer

An aldose contains an aldehyde group, while a ketose contains a ketone group.

Question 13

Which of the following is true about the glycosidic bond in maltose?

Accepted Answer

It is an $$\alpha(1 \rightarrow 4)$$ bond between two glucose units.

Question 14

Which of the following best explains why all monosaccharides are reducing sugars?

Accepted Answer

They all have a free carbonyl group or can convert to one under mild conditions.

Question 15

Which of the following is a correct description of chitin?

Accepted Answer

It is a polysaccharide made of N-acetylglucosamine units with $$\beta(1 \rightarrow 4)$$ bonds.

Question 16

A blood transfusion is safest when the donor has which blood type, and why?

Accepted Answer

Type O, because its cell surface trisaccharide is present on all blood types and is not recognized as foreign.

Question 17

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

Accepted Answer

D-mannose

Question 18

Which of the following best describes the structure of amylopectin?

Accepted Answer

It is a branched polysaccharide with $$\alpha(1 \rightarrow 4)$$ main chains and $$\alpha(1 \rightarrow 6)$$ branches every 25 units.

Question 19

Which of the following is a real-life application of the concept of glycosidic bonds?

Accepted Answer

The inability to hydrolyze the $$\beta(1 \rightarrow 4)$$ bond in lactose leads to lactose intolerance.

Carbohydrates: Life’s Sweet Molecules – Study Guide

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