Cell Membrane::

     The animal cell is surrounded by a double layer of lipid molecules called the cell membrane. The cell membrane gives the entire cell support and protection just like the bark of a tree gives a tree support and protection. If a cell did not have a cell membrane, there would be nothing to keep the cell organelles inside the cell. The cell membrane is also selectively permeable, as it allows certain molecules that the cell is in demand of to pass through the pores in the cell membrane while it doesn't allow toxic molecules to pass through the cell membrane inside the cell. The cell membrane can change shape rather easily, so the cell can be more suited to its function.