Q. What are the organic chemical groups that describe carbohydrates? How are carbohydrates classified according to the presence of those groups?
Carbohydrates are also known as sugars (cellulose, starches and other substances are carbohydrates too).
Carbohydrates are polyhydroxylated ketones or polyhydroxylated aldehydes (polyalcohol ketones or polyalcohol aldehydes).
Polyhydroxylated ketones are called ketoses and Polyhydroxylated aldehydes are called aldoses.