Question

A cell wall of fungi is made up of
a. Cellulose
b. Pectin
c. Chitin
d. Peptidoglycan

Answer 1

Hint: This complex polysaccharide creates the rigidity in the fungal cell walls. It is also present in the insect exoskeleton and gives the cell walls of the fungi structural strength. The wall protects the cell against desiccation and predation.

Complete answer:
> Option A is incorrect. Cellulose is an essential structural component of a green plant's primary cell wall, many algae types, and the oomycetes. It is secreted by certain bacterial organisms to form biofilms. Most prevalent organic material on Earth is cellulose.

> Option B is incorrect. Pectin is a compact, acidic heteropolysaccharide found in terrestrial plant's primary and middle lamella and cell walls. Its main constituent is galacturonic acid, a galactose-derived sugar acid.

> Option C is correct. Chitin is a long-chain N-acetylglucosamine polymer and is a glucose derivative. This polysaccharide is a primary component of cell walls in the fungi, arthropod exoskeletons such as crustaceans and insects, mollusc’s radula, cephalopod beaks, and fish and loss amphibian scales.

> Option D is incorrect. Peptidoglycan or murein is a polymer composed of sugars and amino acids that form a mesh-like layer outside most bacteria's plasma membrane, forming the cell wall. The sugar portion is composed of alternating residues of N-acetylglucosamine and N-acetylmuramic acid linked to β.
So, the correct answer is Option C.

Additional information:
The fungal cell wall is a complex and versatile structure that generally consists of chitin, α- and β-glucans, glycoproteins, and pigments. This structure plays multiple roles by providing cell rigidity and determining the form of the cells; metabolism; protective ion exchange from osmotic stress; and serves as a carbohydrate and receptor reservoir that plays key events during host interaction. Sometimes the fungal cell wall forms the interface between pathogenic fungi and their host for contact.

Note: Chitin is now seen as a possible target for new antimicrobial drugs and remains an intensive research field. There's plenty to learn about the supramolecular structure of the cell wall, the arrangement of its biomolecules and their interfaces.