The cell membrane essentially controls what enters and leaves the cell. The membrane is composed of a phospholipid bilayer, which is hydrophobic, and therefore most soluble substances (anything that's polar or dissolves like water or ions) cannot enter directly through the membrane
the semipermeable membrane surrounding the cytoplasm of a cell.
Explanation:
The cell membrane controls the movement of substances in and out of cells and organelles. In this way, it is selectively permeable to ions and organic molecules.
