1. Cell Membrane Plasma Membrane

2. Cell Membrane 2 layers (bilayer) of phospholipids Similar to a mayonnaise sandwich –2 pieces of bread with may stuck together Each individual phosphoplipid has a –head that is hydrophilic –tail that is hydrophobic

3. The phospholipid

4. STOP!! BIG WORDS!!!! Hydrophobic: Hydro = Water ; Phobic = afraid –The tail of the phospholipid is hydrophobic Hydrophilic: Hydro = Water ; Philic = loving –The head of the phospholipid is hydrophilic Millions of these molecules line up together to form a cell membrane!

5. What is the cell membrane for? Controls material going into the cell Controls material going out of the cell Holds the cell together Able to “talk” with other cells and molecules Phospholipid Head Tail

6. Cell Membrane

8. Membrane looks big? Picture this……. It would take 10,000 membranes to equal the thickness of one sheet of paper!!!

9. Cell Membrane Proteins Proteins are stuck throughout the cell membrane They act as tunnels letting large molecules into and out of the cell

10. Receptor Molecules Molecules that that help the cell “talk” with other cells or molecules Must fit together like a puzzle piece

11. Keep in mind…... Not all substances can pass through the cell membrane!!! Only certain substances when needed…….this is called SELECTIVE PERMEABILITY …. Know what this means……