GED Science Practice

Which of the following is a polymer that provides structure in the shells of insects and lobsters?

1. Cellulose

2. Cholesterol

3. Chitan

4. Chlorophyll

The correct answer is: Chitan

The correct answer is chitin, which is indeed a polymer that provides structural support in the exoskeletons of insects and the shells of crustaceans, such as lobsters. Chitin is composed of long chains of N-acetylglucosamine, a derivative of glucose, and it forms a tough, protective layer that contributes to the rigidity and durability of these organisms' shells. Other options such as cellulose, cholesterol, and chlorophyll serve different biological functions. Cellulose is a polysaccharide that primarily provides structural support in plant cell walls. Cholesterol is a type of lipid important for membrane structure and fluidity in animal cells, while chlorophyll is a pigment crucial for photosynthesis in plants. Each of these substances plays significant roles in various biological processes, but chitin is uniquely suited for providing exoskeletal structure in arthropods.