Monosaccharides - The Simple Sugars

Monosaccharides are relatively small molecules made of a single sugar unit. Glucose, with the chemical formula C6H12O6, is the best-known example; because it contains six carbon atoms it is classed as a hexose. Every monosaccharide carries one of two possible functional groups: some, like glucose, carry an aldehyde group and are called aldoses; others, like fructose, carry a ketone group and are called ketoses. Monosaccharides are also classified by their number of carbon atoms - trioses (3C, e.g., glyceraldehyde), tetroses (4C, e.g., erythrose), pentoses (5C, e.g., ribose) and hexoses (6C, e.g., glucose, fructose). Glucose is of special biological importance as the primary fuel for cellular respiration: i …