From NuGOwiki

Carbohydrates or saccharides are simple molecules that are straight-chain aldehydes or ketones with many hydroxyl groups added. Carbohydrates are the most abundant biological molecules, and fill numerous roles in living things, such as the storage and transport of energy (starch, glycogen) and structural components (cellulose in plants, chitin in animals). Additionally, carbohydrates and their derivatives play major roles in the functioning of the immune system, fertilization, pathogenesis, blood clotting, and development. The basic carbohydrate units are called monosaccharidesand the general chemical formula of an unmodified monosaccharide is (C·H2O)n, where n is any number of three or greater. All carbohydrates have a hydrogen to oxygen ratio of 2:1. Find more on carbohydrates on Wikipedia.