$$\begin{array}{c}CHO \\ HCOH \\ HOCH \\ HCOH \\ HCOH \\ CH_2OH\end{array}$$

Question 1

Which of the following best describes the relationship between D-glucose and D-mannose?

Accepted Answer

They are epimers.

Question 2

In the formation of a hemiacetal from an aldehyde and an alcohol, which atom acts as the nucleophile?

Accepted Answer

The oxygen atom of the alcohol

Question 3

Which of the following statements about anomers is correct?

Accepted Answer

Anomers differ at the new asymmetric carbon formed during ring closure.

Question 4

Which of the following is the correct Fischer projection for D-glucose?

Accepted Answer

$$\begin{array}{c}CHO \ HCOH \ HOCH \ HCOH \ HCOH \ CH_2OH\end{array}$$

Question 5

Which of the following best describes the difference between constitutional isomers and stereoisomers?

Accepted Answer

Constitutional isomers differ in the order of attachment of atoms; stereoisomers have the same order but differ in spatial arrangement.

Question 6

Which of the following is a real-life example of a glycosidic bond?

Accepted Answer

The bond between glucose units in glycogen

Question 7

Which of the following is true about enantiomers?

Accepted Answer

They are nonsuperimposable mirror images.

Question 8

During the cyclization of D-glucose to form a pyranose ring, which functional groups react?

Accepted Answer

The aldehyde group and the hydroxyl group on C-5

Question 9

Which of the following best describes the structure of glycogen?

Accepted Answer

A branched polymer of glucose with both $$\alpha-1$$,4- and $$\alpha-1$$,6-glycosidic bonds

Question 10

Which of the following is the correct definition of an epimer?

Accepted Answer

Isomers that differ at only one asymmetric carbon

Question 11

A patient with a deficiency in the enzyme that forms $$\alpha-1$$,6-glycosidic bonds would have trouble synthesizing which structure?

Accepted Answer

Glycogen

Question 12

Which of the following reactions is an example of a nucleophilic addition?

Accepted Answer

The reaction of an aldehyde with an alcohol to form a hemiacetal

Question 13

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

Accepted Answer

The hydroxyl group on C-4 is on the right.

Question 14

Which of the following best explains why glucose forms a six-membered ring (pyranose) in solution?

Accepted Answer

The hydroxyl group on C-5 attacks the carbonyl carbon, forming a stable six-membered ring.

Question 15

Which of the following is a correct description of diastereomers?

Accepted Answer

Isomers that are not mirror images and differ at one or more chiral centers

Question 16

Which of the following best describes the role of the glycosidic bond in polysaccharides?

Accepted Answer

It links monosaccharides together.

Question 17

Which of the following is the correct general formula for a monosaccharide?

Accepted Answer

$$C_nH_{2n}O_n$$

Question 18

Which of the following is a real-life consequence of the stereochemistry of sugars in medicine?

Accepted Answer

Only D-glucose can be metabolized efficiently by human cells.

Study Guidance for Carbohydrate Chemistry: Isomers, Fischer Projections, and Hemiacetal Formation

Guida di studio - Domande di pratica