1. Cell Membranes Osmosis and Diffusion This Powerpoint is hosted on www.worldofteaching.comwww.worldofteaching.com Please visit for 100’s more free powerpoints

2. Ticket Out Your ticket-out today will be to identify and explain at least 3 topics we discussed in class today. What do you not understand? What do you understand better today than yesterday? This must be turned in as you leave today!

3. Refresher What is a Solute? What is a Solution? What is a Solvent? How are these important? Let’s find out.

4. Functions of Membranes 1. Protect cell 2. Control incoming and outgoing substances 3. Maintain ion concentrations of various substances 4. Selectively permeable - allows some molecules in, others are kept out

5. Phospholipid Bilayer

6. Fluid Mosaic Model

7. Solutions Solutions are made of solute and a solvent Solvent - the liquid into which the solute is poured and dissolved. Solute - substance that is dissolved or put into the solvent. Salt and sucrose are solutes.

8. Methods of Transport Across Membranes 1. Diffusion 2. Osmosis 3. Facilitated Diffusion 4. Active Transport

9. Methods of Transport Across Membranes 1. Diffusion -passive transport - no NRG req. 2. Osmosis - Passive transport of water across membrane (no NRG required) 3. Facilitated Diffusion - Use of proteins to carry polar molecules or ions across (no NRG req) 4. Active Transport- requires energy to transport molecules against a concentration gradient – energy is in the form of ATP

10. Diffusion Movement of molecules from an area of high concentration to an area of low concentration. Movement from one side of a membrane to another, un-facilitated (no NRG required)

11. Diffusion

12. Osmosis

13. Tonicity is a relative term Hypotonic SolutionHypotonic Solution - One solution has a lower concentration of solute than another. Hypertonic SolutionHypertonic Solution - one solution has a higher concentration of solute than another. Isotonic SolutionIsotonic Solution - both solutions have same concentrations of solute.

14. Let’s Draw This Out First – Hypotonic, which way will the water flow? Outside Cell Membrane Inside Cell

15. Second – Hypertonic, which way will the water flow? Outside Cell Membrane Inside Cell

16. Third – Isotonic, which way will the water flow? Outside cell Membrane Inside Cell

17. Plant and Animal Cells put into various solutions

18. Types of Transport

19. Facilitated and Active Diffusion See Overhead

20. Now let’s get into groups (which I will pick) at the lab tables and create our own cell membrane. Please do a good job so we can put them up on the wall. I will go over the directions when we get to the lab tables. Please listen and follow all directions.

21. Homework Please complete the Endocytosis and Exocytosis worksheet (pgs 182-189). Please complete the diffusion and osmosis chart (if have not already done so during the notes) You will be having a quiz over this next class period – I suggest you study!