Question

When discussing sugars, what are intramolecular hemiacetals and hemiketals and why are they important? Give two examples

Answer 1

aldehydes and ketones react with alcohols to form hemiacetals and hemiketals, respectively, carbohydrates react intermolecularly to form rings. When forming a ring 5 or 6 membered ring is most favorable and will only be formed. The Carbon 1 will be attacked by either the Carbon 5 or Carbon 6 hydroxyl group to form a 5 or 6 membered (respectively)carbohydrate ring.

The carbohydrates are a major source of metabolic energy, both for plants and for animals that depend on plants for food. Aside from the sugars and starches that meet this vital nutritional role, carbohydrates also serve as a structural material (cellulose), a component of the energy transport compound ATP, recognition sites on cell surfaces, and one of three essential components of DNA and RNA. Carbohydrates are called saccharides or, if they are relatively small, sugars.