Question 1

Which of the following best describes a Haworth projection?

Accepted Answer

A three-dimensional representation of a cyclic monosaccharide with the ring viewed from the side.

Question 2

When converting a Fischer projection of a monosaccharide to a Haworth projection, which group typically attacks the carbonyl carbon to form the cyclic structure?

Accepted Answer

The hydroxyl group on the penultimate carbon (second to last carbon)

Question 3

In the Haworth projection of D-glucose, which carbon is designated as the anomeric carbon?

Accepted Answer

The carbon that was the carbonyl carbon in the open-chain form (C1)

Question 4

Which of the following statements is TRUE regarding the orientation of groups in a Haworth projection?

Accepted Answer

Groups on the right in a Fischer projection point down in the Haworth projection.

Question 5

A student is converting the Fischer projection of D-galactose to a Haworth projection. Which of the following is a common mistake to avoid?

Accepted Answer

Placing the CH2OH group below the ring instead of above for a D-sugar.

Question 6

Which of the following best explains why cyclic hemiacetals are formed from monosaccharides?

Accepted Answer

The nucleophilic attack of a hydroxyl group on the carbonyl carbon creates a new ring structure.

Question 7

Given the following Fischer projection of D-glucose, which group will be DOWN in the Haworth projection at carbon 2?

Accepted Answer

The hydroxyl group (OH)

Question 8

Which of the following is the correct sequence of steps to convert a bond-line formula of a monosaccharide to a Haworth projection?

Accepted Answer

Identify the ring size, locate the anomeric carbon, assign up/down positions based on the Fischer projection, and draw the ring with substituents.

Question 9

In a Haworth projection, what does the thickened bond typically represent?

Accepted Answer

The part of the ring closest to the viewer

Question 10

A patient’s blood sample contains a high concentration of the alpha-anomer of D-glucose. In the Haworth projection, how is the OH group on the anomeric carbon oriented?

Accepted Answer

Down, opposite to the CH2OH group

Question 11

Which of the following best describes the relationship between the alpha and beta anomers of a cyclic monosaccharide?

Accepted Answer

They differ in the configuration at the anomeric carbon.

Question 12

If a cyclic monosaccharide is drawn as a Haworth projection with all substituents on the same side of the ring, what is the most likely error?

Accepted Answer

The student did not correctly assign up/down positions based on the Fischer projection.

Question 13

Which of the following is a correct statement about the formation of a Haworth projection from a bond-line formula?

Accepted Answer

The ring is drawn with the oxygen at the upper right, and the anomeric carbon is to its right.

Question 14

A chemist is analyzing a Haworth projection and notices that the CH2OH group is pointing up. What does this indicate about the sugar?

Accepted Answer

It is a D-sugar.

Question 15

Which of the following is the correct formula for the formation of a cyclic hemiacetal from an aldehyde and an alcohol?

Accepted Answer

$$ \mathrm{RCHO} + \mathrm{R'OH} \rightarrow \mathrm{RCH(OH)OR'} $$

Haworth Projections and Cyclic Hemiacetals in Carbohydrate Chemistry

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