What type of molecule is glycogen?

Glycogen is a polymer of glucose, which means it is composed of many glucose units linked together via glycosidic bonds. This polysaccharide serves as a key energy storage form in animals and fungi. Structurally, glycogen consists of branched chains of glucose molecules, enabling it to be stored efficiently and broken down quickly when energy is needed.

The branching allows for rapid mobilization of glucose units during periods of energy demand, such as during physical activity or fasting. In contrast to other types of polysaccharides, like starch, which are primarily linear or less branched, glycogen's highly branched structure provides a significant advantage in energy release mechanisms.

Insight into the structure and function of glycogen can also highlight the distinct roles of other mentioned molecules. Fructose, for instance, is a monosaccharide and not a polymer, while proteins and amino acids represent a completely different class of biological molecules, related to the building blocks of enzymes, hormones, and other critical cellular components.