Glycogen and cellulose are polysaccharides formed from glucose fragments. Glycogen accumulates in the cells of fungi and animals as a spare fast source of energy. Cellulose is found in the cell walls of plants. The chemical bond in glycogen is α(1-4), with branching α(1-6). In cellulose, the bond between glucose molecules is β(1-4). Thus, glycogen molecules have a spherical shape, and cellulose molecules are linear.