Question

One of the major components of cell wall of fungi is
A. Chitin
B. Peptidoglycan
C. Cellulose
D. Hemicellulose

Answer 1

Due to the presence of cellulose in the cell wall of the plant, the plants are not directly digestible by humans, as they lack a cellulase enzyme. The polymers of N-acetyl glucosamine are also known as fungal cellulose.

Complete answer:
The cell wall is an outermost, rigid layer that provides support to the cell. The presence of a cell wall is a characteristic feature of plants, fungi and bacteria. It is absent in animals. The fungi are the group of eukaryotic cells that are saprotrophic in nature and include yeasts, mushrooms and moulds. The cell wall of fungus is mainly made up of chitin, glycans and glycoproteins. It provides rigidity and shape to the cell and helps in ion exchange and metabolism. Chitin is a homo-polysaccharide which is made up of N-acetyl glucosamine (NAG). The peptidoglycan is the major component of the cell wall of bacteria. In Gram-positive bacteria, a thick layer of peptidoglycan and teichoic acid is present in the cell wall, due to which it is unable to get the pink colour of safranin dye. It appears violet in colour. In Gram-negative bacteria, a thin layer of peptidoglycan layer is present in the cell wall, due to which it gets the pink colour of safranin dye. It appears pink in colour. The cellulose is the major component of the cell wall of plants and algae. Cellulose is a homopolysaccharide of the glucose molecule. It is the most abundant organic molecule on earth. It is digested by a cellulase enzyme. The hemicellulose is a heteropolysaccharide, made up of galactose, mannose and arabinose. It is present in the cell wall of plants and acts as cementing in ground substance.
So, the correct answer is option A, chitin.

Note:- The chitin is also found in the body wall of arthropods like insects, spiders, scorpions etc. It is the second most abundant organic molecule on earth.The cellulose is absent in true fungi.