Chitin is a polysaccharide that is a key component of the exoskeleton of arthropods, such as insects and crustaceans, as well as the cell walls of some fungi. It is a linear polymer composed of N-acetylglucosamine, a type of sugar, linked together by beta-(1,4) glycosidic bonds. Chitin is strong and durable, making it ideal for use in protective structures. In arthropods, chitin provides support and protection for the body and helps maintain its shape. In fungi, chitin provides rigidity to the cell walls and helps maintain the shape of the fungal body. Additionally, chitin has been found to have various biomedical applications, such as wound healing, drug delivery, and tissue engineering.