A Level Biology Practice Exam

What type of polysaccharide is commonly used for energy storage in animal cells?

1. Starch

2. Glycogen

3. Cellulose

4. Chitin

The correct answer is: Glycogen

Glycogen is the polysaccharide most commonly used for energy storage in animal cells. This complex carbohydrate is primarily stored in the liver and muscle tissues of animals and serves as a key form of energy reserve. When energy is needed, glycogen can be quickly mobilized and broken down into glucose, which can then be utilized by cells for immediate energy. This specific structure allows for rapid release of glucose, making it particularly efficient for meeting the high energy demands of active animal cells. In contrast, starch, while also a storage polysaccharide, is primarily found in plants, and cellulose serves structural purposes in plant cell walls. Chitin also serves a structural role, primarily in the exoskeletons of arthropods and the cell walls of fungi, and is not involved in energy storage in animal cells.