The cell wall is the structure found in plant cells and not in animal cells. The cell wall is a thick, fairly rigid layer formed around individual plant cells. The cell wall is external to the cell membrane and serves a structural function helping the cell maintain its shape and the protecting the cell from damage.
The cell wall is semipermeable. This means it regulates the kind of molecules that come in and out of the cell. Cell walls are also found in bacteria, archaea, fungi, and algae. The cell wall is made up of cellulose, proteins, and aromatics, which contribute to the multi-layered structure of the cell wall.