1. Cell Membranes Osmosis and Diffusion

2. 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

3. Phospholipid Bilayer

4. Fluid Mosaic Model

5. Solutions Solutions are made of solute and a solvent
Solvent - the liquid into which the solute is poured and dissolved..
Solute - substance that is being dissolved or put into the solvent.

6. Methods of Transport Across Membranes
1. Diffusion
Osmosis
3. Active Transport

7. Methods of Transport Across Membranes
1. Diffusion -passive transport - no energy expended
2. Osmosis - Passive transport of water across membrane
3. Active Transport- requires energy to transport molecules against a concentration gradient – energy is in the form of ATP

8. Diffusion
1. Diffusion –is the Mixing of two fluids. This is done without any Chemical reaction or any external force causing the mixture to occur.
passive transport – no energy

9. 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

10. Diffusion

11. Osmosis
A specific type of diffusion where a solvent passes through a semipermeable membrane.
The movement of materials goes from a low solute concentration to a high concentration.
Passive transport of water across membrane

12. Osmosis

13. Tonicity (the tension or the pressure put on the membrane of the cell)
Hypotonic Solution - One solution has a lower concentration of solute than another.
Hypertonic Solution - one solution has a higher concentration of solute than another.
Isotonic Solution - both solutions have same concentrations of solute.

14. Plant and Animal Cells put into
various solutions

15. Types of Transport

16. This powerpoint was kindly donated to www.worldofteaching.com
is home to over a thousand powerpoints submitted by teachers. This is a completely free site and requires no registration. Please visit and I hope it will help in your teaching.