What is the difference between a cell wall and a cell membrane?

The cell membrane (plasma membrane) is present in all cells, both plant and animal. It is thin, living and made of lipids and proteins. Its main feature is that it is selectively permeable, meaning it controls which substances enter and leave the cell. The cell wall is found only in plant cells, fungi and bacteria, not in animal cells. It lies outside the cell membrane, is thick, non-living and made mainly of cellulose in plants. The cell wall is fully permeable and gives the cell rigidity, shape and protection. A simple way to remember: the membrane is the gatekeeper that decides what passes, while the wall is the outer protective fence that supports and shapes the plant cell.