The chitinous exoskeleton of arthopods is formed by the polymerisation of
(1) keratin sulphate and chondroitin sulphate
(3) N-acetyl glucosamine
(3) The chitinous exoskeleton of arthropods is formed by the polymerisation of N-acetyl glucosamine, which is a derivative of glucose. It is also a characteristic component of the cell wall of fungi, the radulae of molluscs and the beaks and internal shells of cephalopods, including squid and octopuses.