Chitin and chitosan provide structural stability to which organism's cell walls?

• A. Bacteria
• B. Plants
• C. Fungi
• D. Archaea

Answer: (C)

Chitin and its derivative chitosan form a sturdy, flexible mesh that is characteristic of fungal cell walls. Chitin is a long polymer of N-acetylglucosamine linked by beta-1,4 bonds, creating a rigid scaffold that helps the cell wall withstand internal turgor pressure and maintain shape. Chitosan, produced by deacetylating chitin, adjusts wall properties like solubility and porosity to support growth and remodeling. This combination is a hallmark of fungi; bacteria rely mainly on peptidoglycan, plants on cellulose, and archaea on other polymers or S-layer structures. So, the cell walls stabilized by chitin and chitosan belong to fungi.