chitin

A complex polysaccharide, a polymer of N-acetylglucosamine, found in the exoskeletons of arthropods and in the cell walls of fungi; thought to be responsible for some forms of asthma in humans.countableuncountable

• Chitin usually occurs throughout Invertebrates in the form of an investment to the outermost cellular layer or ectoderm.
• The robot’s energy source is the sugar in the polysaccharide called chitin that makes up a fly’s exoskeleton.