The exoskeleton of arthropods is composed of chitin.


Chitin is a complex carbohydrate that forms the major component of the exoskeleton of arthropods, such as insects, spiders, crustaceans, and other related organisms. It is also found in the cell walls of fungi and the beaks of cephalopods.


Chitin is a long-chain polymer made up of repeating units of N-acetylglucosamine (a modified form of glucose) joined together by β-1,4 glycosidic linkages. These units form a strong and flexible structure that provides protection and support to the arthropods.


The exoskeleton serves many important functions in arthropods, including:

1. Protection: The chitinous exoskeleton forms a hard and rigid outer covering that protects the soft tissues and organs of the arthropod from mechanical damage, predators, and environmental stresses.

2. Support: The exoskeleton provides structural support to the arthropod's body, allowing it to maintain its shape and resist deformation.

3. Attachment: Muscles are attached to the exoskeleton, allowing the arthropod to move its appendages and carry out various activities such as walking, flying, and swimming.

4. Prevention of Water Loss: The chitinous exoskeleton is impermeable to water, preventing excessive water loss from the arthropod's body and helping to maintain proper hydration.

5. Sensory Function: The exoskeleton contains sensory structures, such as hairs and setae, that enable the arthropod to detect physical stimuli from the environment, such as touch, vibration, and temperature changes.


As arthropods grow, their exoskeleton becomes too small and rigid to accommodate their increasing size. To overcome this limitation, they undergo a process called molting or ecdysis. During molting, the old exoskeleton is shed, and a new, larger exoskeleton is formed underneath. The process of molting is regulated by hormones, and it allows the arthropod to grow and develop into its new exoskeleton.

In conclusion, the exoskeleton of arthropods is composed of chitin, a complex carbohydrate that provides protection, support, and various other functions essential for the survival and success of these diverse organisms.