cell wall is a tough, rigid layer that surrounds some types of cells. Cell wall is a characteristic feature to cells of plants, bacteria, fungi, algae and some archaea. It is located outside the cell membrane. The major function of the cell wall is to provide rigidity, tensile strength, structural support, protection against mechanical stress and infection. It also aids in diffusion of gases in and out of the cell.
Cell wall composition varies from species to species and also depends on the developing stage of the organism. Protozoans and animals do not have a cell wall.