What polysaccharide contributes to the toughness and flexibility of an exoskeleton?

The polysaccharide that contributes to the toughness and flexibility of an exoskeleton is chitin. Chitin is a long-chain polymer made of N-acetylglucosamine, a derivative of glucose. This structure provides significant strength and resilience, making it an ideal material for the exoskeletons of arthropods like insects, crustaceans, and arachnids.

Chitin not only offers mechanical support and protection for these organisms but also allows for some flexibility, enabling movement while maintaining structural integrity. This balance of toughness and pliability is essential for the survival of these species, as their exoskeletons can endure various physical stresses while allowing them to engage in activities like movement and predation.

While cellulose is primarily found in plant cell walls and provides rigidity rather than flexibility, keratin is a fibrous protein found in skin, hair, and feathers, contributing to durability rather than serving as a primary component of exoskeletons. Sclerotin refers to a hardening protein in the exoskeletons of certain invertebrates but does not serve as the primary polysaccharide component; rather, it works alongside chitin to enhance structural features. Thus, chitin is specifically recognized for its role in forming a flexible but