Population Statistics within the Arizona Department of Administration and does not necessarily reflect the official position of the U.S. Department of Labor. The Department of Labor makes no guarantees, warranties,
The Cell Membrane. The Structure of the Cell Membrane. The cell membrane (or plasma membrane) surrounds all living cells, and is the cell's most important organelle. It controls how substances can move in and out of the cell and is responsible for many other properties of the cell as well.
The cell membrane is often included in sections about the structure and functions of cell organelles. However, the cell membrane (also known as the plasma membrane) is not within the cell but one of the structures that defines the cell - together with the cell wall in the cases of plant cells and prokaryotic cells. See functions of the cell membrane.