Glycogen is the primary energy storage molecule in which group?

• A. Plants
• B. Bacteria
• C. Animals
• D. Fungi

Answer: (C)

Glycogen serves as the quick-access energy reserve in animals. It is a highly branched polymer of glucose, which allows many ends for rapid breakdown when energy is needed. In animals, most glycogen is stored in the liver and skeletal muscles. Liver glycogen helps keep blood glucose levels stable between meals, while muscle glycogen provides immediate fuel during activity. This fast-access storage suits the energy demands of animals, which can shift quickly from rest to movement. Plants store energy primarily as starch for long-term storage in seeds and tissues, not glycogen. Fungi and some bacteria also use glycogen, but the strongest association students learn is that animals rely on glycogen for quick energy.