What regulates the cell's structure by selecting what enters (like a gated community)?
The cell membrane also known as the plasma membrane is a part of the cell’s structure that regulates what goes in or out of a cell. The membrane protects the internal structures of the cell from the external environment, thus forms the outermost part of the cell. Its structure is selectively permeable and this is what gives it the regulative capabilities, of allowing the ‘right’ molecules and ions through while keeping out the ‘wrong’ ones. It does the same for molecules moving out of the cell from the internal structures. The cell membrane also has other useful features which include;
Cell adhesion- This is the ability to bind on the surface of other cell membranes. This is important in the development and maintenance of a multi-cellular structure.
Cell signaling- This follows from cell adhesion, where the bound cells are able to communicate by transmitting signals between each other.