Polysaccharides are molecules made of more than one sugar molecule. There are hundreds of different types of polysaccharides, which provide critical structural and functional support for cells in the body. Among the most important polysaccharides are cellulose, glycogen, and chitin. These polysaccharides provide structural support for cells, store energy, and are important for cell signaling. Other polysaccharides play a role in health, including polyketides (derived from amino acids), proteoglycans (glycoproteins), and oligosaccharides (small saccharides).