1. The plasma (Cell) membrane

2. Cell Membrane (Plasma Membrane): forms a boundary between a cell and the outside environment.

3. Maintaining balance
Cells must keep a balance inside the cell and be able to eliminate wastes.
The plasma membrane does this by controlling the passage of materials into and out of the cell.

4. Maintaining balance
Selective permeability means that the plasma membrane is able to allow some materials to pass while keeping others out.

5. Structure The cell membrane is a phospholipid bilayer.
It contains two layers of several phospholipids/ lipid molecules with proteins embedded.
A phospholipid is composed of three basic parts

6. Phospholipid

7. Cell Membrane-fluid mosaic model

8. The plasma (cell) membrane

9. The lipid bilayer
The phosphate group is attracted to water (hydrophilic ).This means polar.
Fatty acid tails don’t like water and are repelled by water (hydrophobic ). This means non-polar.

10. The membrane proteins
The proteins determine which particles can pass and act as markers and receptors to signal molecules where they can go or what they can do.