1. The rigid, protective and supportive covering, outside the cell membrane is called cell wall. It is present in plant cells, fungi and some protists.
2. Algae show presence of cellulose, galactans, mannans and minerals like calcium carbonate in cell wall.
3. In other plants, it is made up of hemicelluloses, pectin, lipids and protein.
4. Microfibrils of plant cell wall show presence of cellulose which is responsible for rigidity.
5. Some of the depositions of cell wall are silica (grass stem), cutin (epidermal walls of land plants), suberin (endodermal cells of root), wax, lignin.
6. Function:
1. Provides support, rigidity and shape to the cell.
2. Protects the protoplasm against mechanical injury and infections.
