1. Cell Processes:
Diffusion and Osmosis

2. Diffusion - the tendency of molecules to move from a higher concentration to a lower concentration until equilibrium is reached.
Equal on right & left
Fully diffused
Higher concentration on the left
Equilizing out

3. Diffusion video

4. Types of Movement in the Cell:
Passive Transport
Diffusion across a semi-permeable membrane (ex: cell membrane).
Cell does not use any energy for diffusion. It goes through the cell membrane without it opening up.
Examples – water, alcohol, O2 and CO2,

5. Osmosis - The diffusion of water
Cell membrane doesn’t open up, just goes through. Only works with very small particles.
Osmosis Video

6. Hypertonic Solution
Solution with a higher concentration of solute and a lower concentration of water.
Makes the cell shrivel. Example: adding salt water
Video Link

7. Hypotonic Solution
Solution with a lower solute concentration and a higher water concentration.
More water moves in than out. Cell bloats. Example: Being in the bath too long causes wrinkled fingers.
Video link

8. Isotonic Solution Equal amount of water goes in and out of cell.
Video link

9. Effect on living cells
Animal
Plant

10. Active Transport
Cell uses energy to move things in and out. Example: food molecules
Cell membrane actually opens and closes.
Active Transport Video

11. Exocytosis & Endocytosis
Exocytosis (molecules “exit” the cell.
Ex: Waste products
Endocytosis (substances “enter” the cell).
Ex: Food molecules