Carbohydrates, also known as sugars, are found in all living organisms. They are essential to the very source of life (ex. Ribose sugars in DNA and RNA) or sustaining life itself (e.g., Metabolic conversion of carbohydrates into usable biochemical energy, ATP). Another important role of carbohydrates is structural (ex. Cellulose in plants). General names for carbohydrates include sugars, starches, saccharides, and polysaccharides. The term saccharide is derived from the Latin word "sacchararum" from the sweet taste of sugars. The name "carbohydrate" means a "hydrate of carbon." The name derives from the general formula of carbohydrate is Cx(H2O)y - x and y may or may not be equal and range in value from 3 to 12 or more. For example glucose is: C6(H2O)6 or is more commonly written, C6H12O6.
Thumbnail: Haworth formula of D-glucose.