Describe how the structure of glycogen allows it to perform its function and explain the advantages to animals of using glycogen as an energy store.

Glycogen is a polysaccharide composed of alpha glucose monomers which are a respiritory substrate involved in the production of energy (ATP). 1-6 glycosidic bonds between glucose allow glycogen to be branched. Glycosidic bonds between glucose molecules are hydrolised to release glucose molecules for respiration. Braches allow for more sites of enzyme activity, so glucose can be released quickly. Since animals are more active than plants and have a higher metabolic rater their energy requirements are greater, aniamls have evolved to use glycogen as it porvides sufficiently fast glucose release.