Class name for the aldehydic or ketonic derivatives of polyhydric alcohols, the name being derived from the fact that the most common monomeric examples of such compounds have formulas that may be written as Cn(H2O)n (e.g., glucose, C6(H2O)6); although they are not true hydrates and the name is, in that sense, a misnomer. The group includes compounds with relatively small molecules, such as the simple sugars (monosaccharides, disaccharides, etc.), as well as macromolecular (polymeric) substances such as starch, glycogen, and cellulose. The carbohydrates most typical of the class contain carbon, hydrogen, and oxygen only, but carbohydrate metabolic intermediates in tissues also contain phosphorus.saccharide