Carbohydrate pertains to a large group of organic compounds made during photosynthesis in green plants and elsewhere. It is also called saccharides.

Carbohydrate is a collective term for various substances with many different chemical properties and biological functions. Their diversity results from the large variety of monosaccharides used as building blocks as well as from the ways in which they are joined to proteins and other complex molecules.

Carbohydrates serve as energy sources, nutritional and other reserves, and structural substances. They occur in all plants and are an essential part of human nutrition. Some carbohydrates cannot be digested by humans, e.g. fibres.

All complex carbohydrates are built up from units of simple sugars (?monosaccharides?) like glucose or fructose. Carbohydrates comprising two sugar units (such as sucrose [table sugar]) are called ?disaccharides?. Larger molecules such as starch are ?polysaccharides?.