Chitin

Chitin is a homopolysaccharide, but unlike cellulose its repeating monomer carries an amino group, technically making it a mucopolysaccharide. Its basic building block is N-acetylglucosamine, a nitrogen-containing derivative of glucose. Chains of N-acetylglucosamine units linked together form chitin's tough, resilient structure. Chitin forms the hard exoskeleton of insects and other arthropods (crustaceans, spiders), giving them mechanical protection and support in the absence of an internal skeleton, and it is also the principal component of the **cell walls of fung …