What is the primary structural polysaccharide found in the rigid cell walls of fungi and the exoskeleton of arthropods such as insects and crustaceans?

💡 Solution & Explanation

Chitin is a tough, fibrous homopolymer composed of N-acetylglucosamine units linked by beta glycosidic bonds, providing structural rigidity to fungal cell walls and insect exoskeletons. Cellulose is the main structural component of plant cell walls, peptidoglycan forms bacterial cell walls, and starch acts as energy storage in plants. Chitin is nitrogen-containing, distinguishing it from pure polysaccharides like cellulose and starch.