The cell-surface membrane = the plasma membrane that surrounds cells and forms a boundary between the cell cytoplasm and the environment.
It allows various conditions to be established between the inside and outside of the cell.
It also controls the movement of substances in and out the cell.
MOLECULES THAT FORM THE STRUCTURE OF THE CELL SURFACE MEMBRANE:
These form a bilayer sheet. They are important because:
- One layer has hydrophilic heads pointing inwards, interacting with the H20 in the cell cytoplasm.
- One layer has hydrophilic heads pointing outwards, interacting with the H20 surrounding all cells.
- Both layers have hydrophobic tails pointing inwards of the membrane, protected from the water in both sides.
They have 3 functions: