Carbohydrate

A carbohydrate is a large biological molecule, or macromolecule, consisting of carbon (C), hydrogen (H), and oxygen (O) atoms.

Quotes

 * The carbohydrates are a broad and diverse class of compounds, responsible for countless functions in biological chemistry. Nonetheless, their chemical behavior and their biological activity arise directly from their structures as polyfunctional molecules with well-defined shapes, which in turn result from their stereochemical characteristics. Their study provides an excellent opportunity to review the properties of the carbonyl and hydroxy functional groups, and to explore how such simple structural components can give rise to a rich array of molecular properties.
 * K. Peter C. Vollhardt, Neil E. Schore (2011) Organic chemistry : structure and function 6th ed. Ch. 24 : Carbohydrates