All of the Statements About the Following Pairs of Sugars

Question

All of the statements about the following pairs of sugars are correct EXCEPT:
A) Galactose and mannose are diastereomers.
B) L-galactose and D-galactose are enatiomers.
C) Glyceraldehyde and dihydroxyacetone are stereoisomers.
D) Glucose and mannose are epimers.
E) Glucose has fewer chiral centers than fructose.

Accepted Answer

Glucose and fructose both have 4 chiral centers (carbon atoms with four different substituents). Therefore, glucose does not have fewer chiral centers than fructose, making statement E incorrect. However, statements A, B, C, and D are all correct. Galactose and mannose are diastereomers because they differ in the orientation of hydroxyl groups at only one carbon atom but not at others, L-galactose and D-galactose are enantiomers because they are mirror images of each other, glyceraldehyde and dihydroxyacetone are stereoisomers because they have the same molecular formula but different arrangement of atoms, and glucose and mannose are epimers because they differ in the orientation of hydroxyl groups at only one carbon atom.