Chitin is a compound found in the cell walls of fungi and the exoskeletons of insects and some other arthropods; composed of chains of nitrogen-containing, modified glucose molecules.
Chitin is different from other polymers of carbohydrates or polysaccharides such as cellulose because of the substitution that occurs on the glucose molecule. Instead of a hydroxyl group (OH), the glucose molecules in chitin have an amyl group attached that consists of carbon and nitrogen.