Starch is also a polysaccharide, like cellulose, but it is much less crystalline. The major component of starch is amylopectin, which is a highly branched polymer, while cellulose is strictly linear. These branches prevent amylopectin from crystallizing as well as cellulose. Starch is an excellent source of energy (or stored sugar) for plants and animals for these reasons: Because it is less crystalline than cellulose it is more soluble than cellulose, and the branched structure also means there are more end groups at which enzymes can start “chewing” the polymer apart.