The major energy storage molecule in animals is what?

• A. Glycogen
• B. Triglycerides (fat)
• C. Glucose
• D. Cholesterol

Answer: (C)

Energy is stored in animals in different forms that fit different time scales. The long-term energy reserve is triglycerides stored in adipose tissue. They pack a lot of energy per gram (about 9 kcal/g) and are mobilized when food isn’t available for extended periods. Glucose acts as the immediate fuel and is stored only briefly as glycogen in liver and muscle, but this glycogen reserve is relatively small compared with fat stores. Cholesterol isn’t used for energy storage; it serves structural and regulatory roles. So the major energy storage molecule is triglycerides (fat).