Cell walls can be composed of polysaccharides, proteins, lipids, or a combination of these. Cell walls provide increased mechanical strength and resistance to lysis by osmotic shock (water moving into the cell). Cell walls are found in the cells of eubacteria, archaebacteria, fungi, algae, and plants.The cell walls vary greatly in their compositions: 1  Eubacteria. 2  Almost all eubacterial species have cell walls containing a polysaccharide called peptidoglycan.ell walls are found in the cells of eubacteria, archaebacteria, fungi, algae, and plants. The cell walls vary greatly in their compositions: 1  Eubacteria. 2  Almost all eubacterial species have cell walls containing a polysaccharide called peptidoglycan.