1. Membrane Structure

2. Review: Phospholipid structure and properties *amphipathic

3. Membrane Models: 1935 Today Cell biology at work: membranes “uncovered” *Membranes are fluid

4. Membranes are fluid

5. *Some functions of membrane proteins: Transport Enzymatic activity Signal transduction Intercellular junction Cell recognition Anchors

6. Membrane Transport *Channel protein *Carrier protein

7. Traffic across membranes *Passive transport *Active transport Passive transport *Selective permeability *Diffusion

8. Osmosis is the passive transport of water When comparing two solutions: *hypertonic *hypotonic *isotonic

9. Passive transport Facilitated diffusion Channel proteins and carrier proteins *Each cell membrane has characteristic set of carrier proteins

10. *Active transport Example: sodium-potassium pump

11. Electrogenic pump: *Some ion pumps generate voltage across membranes *Voltage *Membrane potential