Glycogen is stored as a polysaccharide in which tissues?

• A. Adipose tissue
• B. Brain
• C. Liver and skeletal muscle
• D. Blood plasma

Answer: (C)

Glycogen is the storage form of glucose in animals, packed as branched polysaccharide granules primarily in liver and skeletal muscle. In the liver, glycogen functions as a system-wide buffer to maintain blood glucose during fasting: it can be broken down and glucose released into the bloodstream when needed. In skeletal muscle, glycogen provides a local energy reserve for contraction during exercise; however, muscles lack the enzyme needed to release free glucose into the blood, so glycogen breakdown meets their own energy demands. Adipose tissue stores energy as triglycerides rather than glycogen, and the brain contains only small amounts of glycogen, since it relies on a steady supply of circulating glucose. Blood plasma is not a storage site for glycogen.