The structure (abbreviated) of the structural polysaccharide chitin, a major component of the exoskeleton of arthropods (spiders, crustaceans, insects, etc.) and of the cell wall of fungi. It is similar to cellulose, but with a different side group on the carbon 2 of glucose. Absorbable surgical thread can be made of this material. Only a small fragment of the potentially infinite polymer is shown. Drawn in Inkscape.