The Fundamental Unit of Life — Science STD 9 — Question

Cell wall: It is a characteristics of plant cell only and absent in animal cell. It is an outer, rigid, protective, supportive and freely permeable covering of plant cells. The cell wall lies outside of the plasma membrane. It determines the shape of a plant cell and prevents desiccation of cells. It is mainly composed up of mainly cellulose. Cellulose is a complex substance and provides mechanical and structural strength to plants.
Function of cell wall:

1. Cell wall provides shape and rigidity to the cell.
2. It protects plasma membrane and internal structures from the attach of pathogens and mechanical injury.
3. It provides mechanical strength to the cell.
4. It is freely permeable to water and substances in solution.