Question 1

Which type of ring structure is most stable for monosaccharides, and why?

Accepted Answer

5- and 6-membered rings, because they minimize ring strain.

Question 2

Which monosaccharide forms a five-membered ring structure known as a furanose?

Accepted Answer

Fructose

Question 3

In a Haworth projection, how does a group that is on the right side of a Fischer projection appear?

Accepted Answer

It points downward.

Question 4

Which carbon is the anomeric carbon in a cyclic D-glucose molecule?

Accepted Answer

The carbonyl carbon (C=O) in the open-chain form, which becomes C1 in the ring.

Question 5

What is the correct sequence for numbering the carbons in a cyclic D-glucose molecule?

Accepted Answer

Start at the anomeric carbon and proceed clockwise around the ring.

Question 6

Which of the following best describes the difference between a pyranose and a furanose ring?

Accepted Answer

A pyranose ring has 6 members, while a furanose ring has 5.

Question 7

Which of the following statements about Haworth projections is TRUE?

Accepted Answer

Haworth projections are planar representations, but actual rings are not planar.

Question 8

If the OH group on the anomeric carbon is trans to the CH2OH group in a D-glucose Haworth projection, which anomer is present?

Accepted Answer

$$\alpha-$$anomer

Question 9

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

Accepted Answer

The ring with the CH2OH group above the plane and the anomeric OH below the plane.

Question 10

A patient’s blood sample reveals a high concentration of D-fructose. Which ring structure is most likely to be present in solution?

Accepted Answer

A five-membered furanose ring.

Question 11

Which of the following best explains why cyclic monosaccharides are more stable as 5- or 6-membered rings?

Accepted Answer

They minimize angle and torsional strain.

Question 12

When converting a Fischer projection to a Haworth projection, which direction do groups on the left of the Fischer projection point in the Haworth projection?

Accepted Answer

Upward

Question 13

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

Accepted Answer

$$\mathrm{C_6H_{12}O_6$}$$

Question 14

Which step is necessary to assign numbers to the carbons in a cyclic monosaccharide?

Accepted Answer

Start numbering at the anomeric carbon and proceed around the ring.

Question 15

Which of the following is a correct statement about the anomeric carbon in cyclic monosaccharides?

Accepted Answer

It is the carbon that was the carbonyl carbon in the open-chain form.

Cyclic Monosaccharides and Haworth Projections

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