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.
Cell Membrane Function. The cell membrane (plasma membrane) is a thin semi-permeable membrane that surrounds the cytoplasm of a cell. Its function is to protect the integrity of the interior of the cell by allowing certain substances into the cell, while keeping other substances out.