Computer graphics representation of a molecule of fructose (also called laevulose or fruit sugar), a simple sugar isomeric with glucose. Saccharides or sugars are comprised of rings of 4 or 5 carbon atoms (green) and one oxygen atom (red). Attached around the ring are hydroxy (OH) groups. Glucose & fructose are monosaccharides - single rings. Sucrose (cane sugar) consists of two rings joined together. Polysaccharides such as starch and cellulose consist of hundreds of glucose rings joined in a chain. Cellulose, the structural material of plants, is one of the most abundant naturally-occurring polymers. The image was modelled using Chemical Design's Chem-X software.