Question

Chitin is composed of
A. Protein and carbohydrates
B. Carbohydrates and mannose
C. Fatty acids and carbohydrates
D. Polysaccharides rich mannose

Answer 1

Hint: There are various types of materials or polymers present in nature. They can be homopolymers and heteropolymers. Different types of macromolecules bind differently to make longer chains or complex structures. These structures can make the exoskeleton of insects and thus, are hard and tough usually.

Complete answer:
Chitin is composed of proteins and carbohydrates. It has amine groups along with glucose units. It is a linear homopolysaccharide made up of N-acetyl-D-glucosamine joined together by beta linkages. It is different from cellulose at the site where the hydroxyl is replaced with the acylated amino group. Chitosan is the deacylated chitin. Chitin is the component present in the exoskeleton of arthropods, insects, etc. After cellulose, chitin is the most abundant polysaccharide. Chitinase is the enzyme that can degrade chitin. It has industrial applications as well. We use chitin in the food industry as stabilizers, preservatives and emulsifiers. In humans, it is sensed in the lungs or gastrointestinal tract where it can activate the innate immune system through eosinophils or macrophages, as well as an adaptive immune response through T helper cells.
Hence, the correct answer is Option (A).

Note: An insect’s cuticle, chitin is linked to the proteins covalently. There are many different chitin protein assemblies available. For example; in insects, the chitin-melanin complex is observed. Melanoprotein is also a complex of chitin and protein. Chitin is a component of the cell wall of fungi. It is anti-fungal in nature so can be used as a preservative agent.