Both protexts the organisms' organelles which are inside the cell.
Animal Cell: Cell Membrane
Plant Cell: Cell Wall
Cell wall is present only in plants, it is not found in all organisms. Compared to the cell membrane, a cell wall is thick and has a rigid structure. You can see it in a light microscope, because it is visible. It serves as the protective cover that surrounds the plasma membrane in a plant cell. Cell membrane is composed of lipids. Cell walls can be made up of cellulose or peptidoglycan or chitin.