what is the chemical composition of carbohydrates
Carbohydrates Carbohydrates (also called saccharides) are molecular compounds made from just three elements: carbon, hydrogen and oxygen. Monosaccharides (e.g. glucose) and disaccharides (e.g. sucrose) are relatively small molecules. They are often called sugars.Other carbohydrate molecules are very large (polysaccharides such as starch and cellulose). Carbohydrates are: 1  a source of energy for the body e.g. glucose and a store of energy, e.g. starch in plants.2  building blocks for polysaccharides (giant carbohydrates), e.g. cellulose in plants and glycogen in the human body. 3  components of other molecules eg DNA, RNA, glycolipids, glycoproteins, ATP.hey are often called sugars. Other carbohydrate molecules are very large (polysaccharides such as starch and cellulose). Carbohydrates are: 1  a source of energy for the body e.g. glucose and a store of energy, e.g. starch in plants.