The reference sugar shown undergoes mutarotation in water. Which of Structures A to D can also undergo mutarotation?

AStructure A
BStructure B
CStructure C
DStructure D

Answer: B, D

Mutarotation needs a free hemiacetal carbon (ring O and OH on the same carbon) so that the ring can open and close to give either anomer. Structure B (beta-D-fructofuranose, with a hemiketal C-2) and D (alpha-D-galactopyranose) have this. A is a methyl glycoside (acetal) and C is glucitol, with no carbonyl or hemiacetal, so neither mutarotates.

Practice Biomolecules More on Anomers, epimers and reducing sugars from drawings

Previous questionNext question

More questions on Anomers, epimers and reducing sugars from drawings

The two cyclic sugars shown (both D-pyranoses) differ in configuration at exactly one ring stereocentre other than the anomeric carbon. They... JEE Main level
The two open-chain sugars shown are both D-aldohexoses. Which description is correct? JEE Main level
The reference compound shown gives a positive Tollens test. Which of Structures A to D also gives a positive Tollens test? JEE Main level
The disaccharide shown has one glycosidic bond. Which description of it is correct? JEE Main level
Assertion (A): The compound shown shows mutarotation when dissolved in water. Reason (R): It contains a free anomeric hydroxyl group, so the... JEE Main level
The glycoside shown has a ring made of how many atoms, and is it a reducing sugar derivative? JEE Main level