1. Membranes Chap. 5

2. Phosophlipids Phospholipids will form a bilayer when placed in water. Phospholipid bilayers are fluid.

3. Membrane Structure Cellular membranes have 7 different components: 1.Phospholipid bilayer 2.Transmembrane protein 3.Interior protein network

4. Membrane Structure Cellular membranes have 7 different components: 4. Cell surface markers 5. Protein pumps 6. Cholesterol 7. Receptor proteins

6. Membrane Protein Functions

7. Diffusion - Passive Transport “Movement of a molecule across a membrane without the use of energy” Diffusion is a form of passive transport.

8. Facilitated Diffusion Facilitated diffusion: “Molecules that cannot cross the membrane easily alone can do so with the help of specific proteins”

9. Active Transport “Movement of a molecule across a membrane with the use of energy”

10. Sodium-Potassium (Na + - K + ) Pump

11. Osmosis The diffusion of water across a semi- permeable membrane.

12. Cells in Solution Isotonic “The concentration of water and dissolved solutes is the same on the inside of the cell and in the solution outside”.

13. Cells in Solution Hypotonic “The concentration of dissolved solutes is lower (and the concentration of water is higher) in the solution than in the cell.

14. Cells in Solution Hypertonic “The concentration of dissolved solutes is higher (and the concentration of water is lower) in the solution than in the cell.

15. Review

17. Bulk Transport - Endocytosis The cell membrane forms a vessicle by surrounding a large molecule or group of molecules. The vessicle brings the molecule(s) into the cell.

18. Bulk Transport - Exocytosis A vessicle is created around a molecule inside the cell. The vessicle attaches to the cell membrane which opens up and releases the molecule outside the cell.