The German cockroach has a hard exoskeleton that covers its body, serving as support and maintaining its shape, while also playing a protective role. The chitin layer is a major component of the cockroach's exoskeleton and is composed of a polymer called chitosan. This chitin layer provides rigidity and structural stability to the cockroach's external structure.

Chitin is also essential for the growth and development of cockroaches, as they must modify and shed their exoskeleton to grow. This process is called molting, during which the old exoskeleton is shed, and a new one grows underneath it. This process would not be possible without the chitin layer that forms its structure.

Chitin is an extremely durable yet flexible material, allowing cockroaches to perform daily activities such as moving and searching for food despite the constraints of the exoskeleton. Additionally, it provides enhanced protection against external factors and the effects of chemical substances.