What role does glycogen serve in animals?

Glycogen serves as a critical energy storage molecule in animals. It is a polysaccharide that is stored primarily in the liver and muscle tissues. When the body requires energy, particularly during periods of fasting or intense activity, glycogen is broken down into glucose molecules. This process occurs through glycogenolysis, allowing for quick mobilization of glucose for energy production, especially during activities that require abrupt bursts of energy, such as sprinting or weightlifting.

By storing glucose in the form of glycogen, animals can efficiently manage their energy needs, ensuring a readily available source of fuel that can be drawn upon when blood glucose levels drop or when energy demands increase. This role is particularly vital for maintaining metabolic homeostasis and sustaining physical activity.