AAMC FL Practice Exam

Reducing sugars can undergo which of the following processes?

1. Mutarotation and ring opening

2. Hydrolysis and dehydration

3. Fermentation and oxidation

4. Condensation and polymerization

The correct answer is: Mutarotation and ring opening

Reducing sugars can undergo mutarotation and ring opening, which is fundamental to their chemical behavior. Mutarotation refers to the change in optical rotation that occurs when anomeric forms of a sugar interconvert in solution. This transformation is significant in the chemistry of carbohydrates, as reducing sugars exist in an equilibrium between their cyclic (ring) forms and their linear forms. Ring opening is a process related to mutarotation where the cyclic structure of the sugar opens up to form the linear form, allowing for further chemical reactions. This ability to switch between forms is a characteristic feature of reducing sugars, which includes monosaccharides such as glucose and fructose. While other processes, such as hydrolysis, fermentation, and polymerization, may involve carbohydrates, they are not exclusive to or define the behavior of reducing sugars specifically. Therefore, the combination of mutarotation and ring opening accurately captures critical processes that define their chemical properties.