Which tissue stores about 500 g of glycogen?

• A. Skeletal muscle
• B. Liver
• C. Adipose tissue
• D. Brain

Answer: (A)

Glycogen is stored mainly in muscle and liver, serving different roles. The majority of the body's glycogen sits in skeletal muscle, where it provides a ready energy source for muscle contraction during activity. This glycogen is used locally and cannot be released into the bloodstream because muscle lacks the enzyme glucose-6-phosphatase.

The liver, by contrast, stores glycogen to help maintain blood glucose during fasting, but its stores are much smaller—around 100 g in many adults—so they don’t reach the several hundred grams seen in muscle.

Adipose tissue stores energy as fat, not glycogen, and the brain uses very little glycogen as an energy buffer. Therefore, a quantity near 500 g best fits skeletal muscle as the main glycogen reservoir.