Glycogen 's the molecule which functions as the secondary short term energy storage in animal cells. It's made primarily by the liver and the muscles, but can also be made by glycogenesis within the brain and stomach. Glycogen's the analogue of starch, a less branched glucose polymer in plants, and's commonly referred to as animal starch, having a similar structure to amylopectin. Glycogen's found in the form of granules in the cytosol in many cell types, and plays an important role in the gluc… (More on Glycogen)