How many stereoisomers are possible for a ketopentose such as ribulose?
A)2
B)4
C)8
D)16
E)32

Name: How many stereoisomers are possible for a ketopentose such as ribulose? A)2 B)4 C)8 D)16 E)32
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Question

Quizplus · Accepted Answer

A ketopentose like ribulose has four chiral centers, which gives a possibility of 2⁴ stereoisomers or 16 stereoisomers. However, two of the configurations are meso forms, which are identical and, therefore, not stereoisomers. This leaves eight different stereoisomers, making option B, "4," the correct answer.

How Many Stereoisomers Are Possible for a Ketopentose Such as Ribulose