Which polymer stores energy in plants?

• A. Starch
• B. Glycogen
• C. Cellulose
• D. Chitin

Answer: (A)

Plants store energy as starch, a glucose polymer kept in plastids like amyloplasts. When energy is needed, enzymes break starch into glucose to fuel cellular processes. Starch is made of two types of glucose links: mostly linear amylose and branched amylopectin, which lets plants pack energy efficiently in seeds, roots, and storage organs. This contrasts with cellulose, which uses different bonds to form rigid fibers for strong cell walls and isn’t an energy reserve, or with chitin, a structural polymer in fungi and arthropods. Glycogen, on the other hand, serves as the storage form of glucose in animals and fungi, not plants. So starch is the appropriate energy-storage polymer in plants.