Glycogen is a _________.

• A. disaccharide
• B. polysaccharide
• C. monosaccharide
• D. oligosaccharide

Answer: (B)

Glycogen is a polysaccharide, a large polymer built from many glucose units. Monosaccharides are single sugar molecules, disaccharides are two sugars, and oligosaccharides have only a few units, whereas glycogen contains hundreds to thousands of glucose units linked together. Its structure is highly branched, with chains of glucose connected by α-1,4-glycosidic bonds and branches formed by α-1,6-glycosidic bonds every so often. This branching makes glycogen an efficient, compact storage form of glucose in animals, readily mobilized for energy when needed.