Polysaccharides are large molecules that feature high molecular weights and contain hundreds of glucose units joined by beta-glycoside bonds between C-1 and C-4 sites of adjacent sugars. They are also called glycans. The most important polysaccharides are cellulose, starch, and glycogen. Glycogen is also made up of glucose molecules. Like starch, it is also used by animals to store sugar as a source of energy. It is similar to amylopectin in structure but it is branched at every tenth glucose unit.