MCAT Biochemistry Question 47: Answer and Explanation

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Question: 47

2. All of the following are true of epimers EXCEPT:

  • A. they differ in configuration about only one carbon.
  • B. they usually have slightly different chemical and physical properties.
  • C. they are diastereomers (with the exception of glyceraldehyde).
  • D. they always have equal but opposite optical activities.

Correct Answer: D

Explanation:

Epimers are monosaccharide diastereomers that differ in their configuration about only one carbon. As with all diastereomers, epimers have different chemical and physical properties, and their optical activities have no relation to each other. Enantiomers have equal but opposite optical activities. Therefore, choice (D) is the only statement that does not apply to epimers.

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