1. Diffusion and Osmosis 1a. Some are too big
1. Some particles are allowed to cross the plasma membrane and some aren’t. Why?
1a. Some are too big
1b. Some are too strongly charged

2. Diffusion and Osmosis
1. Some particles are allowed to cross the plasma membrane and some aren’t. Why?
(continued)
1c. PERMEABLE
Molecules that CAN go through the plasma membrane.
1d. IMPERMEABLE
A molecule that CAN NOT go through the plasma membrane.

3. Diffusion and Osmosis
2. How do permeable materials get across the membrane?
2a. Passive Transport
Materials move across easily without the cell doing any work.
(NO ENERGY NEEDED)
2b. Active Transport
Materials require the cell to use energy to get across the membrane.
(ENERGY NEEDED)

4. Active vs. Passive Transport

5. Active vs. Passive Transport
DRAW this Venn diagram in your notebook. Make it nice and big (about half a page).

6. Diffusion and Osmosis 3. What are the two types of Passive Transport?
3a. Simple Diffusion
Particles move directly through the plasma membrane. (Good for small uncharged molecules).
3b. Facilitated Diffusion
Particles need protein channels to get through the plasma membrane. (Good for larger, slightly charged molecules)

7. HIGH LOW CONCENTRATION CONCENTRATION
Diffusion and Osmosis
4. How does diffusion work?
4a. Particles tend to move from areas of:
HIGH LOW CONCENTRATION CONCENTRATION

8. Concentration gradient
Concentration Gradient - change in the concentration of a substance from one area to another.
Moving “with the concentration gradient” means moving from HIGH to LOW concentration.

9. Diffusion is…
movement of molecules from an area of high concentration to an area of lower concentration. (“spreading out”)

10. Which direction will the molecules diffuse in each of the figures below?1 2 3 4 5 6

11. Diffusion and Osmosis
5. What is
Osmosis?
5a. The process by which WATER MOLECULES diffuse across the plasma membrane.

12. Diffusion and Osmosis
6. Summary

13. Amoeba Sisters Video: Osmosis

14. Diffusion and Osmosis
7. Solutions
7a. Except for pure water, all solutions have something dissolved in them
7b. Solute
- The dissolved substance in the
solution

15. Diffusion and Osmosis 7c. Isotonic
7. Solutions
(continued)
7c. Isotonic
- When two different solutions have the
same concentration of solute.

16. Diffusion and Osmosis 7d. Hypertonic
7. Solutions
(continued)
7d. Hypertonic
- A solution with a higher concentration
of solute.

17. Diffusion and Osmosis 7e. Hypotonic - A solution with the lower
7. Solutions
(continued)
7e. Hypotonic
- A solution with the lower
concentration of solute

18. Osmosis: Solutions

19. Example 1
Draw an arrow to show which way the water would move by osmosis.
Fill in any missing percentages (water or solute)
Identify the type of solution (isotonic, hypertonic, hypotonic)

20. Example 2
What will happen to the size of a cell that has a solute concentration of 5% is placed in a 1% saltwater concentration?

21. Passive Transport Recap

22. Diffusion and Osmosis
8. Active Transport
8a. Active Transport - requires the use of energy (ATP ) by the cell to move materials in or out.
8b. Active Transport is used when moving:
Materials against the concentration gradient
Ions of the same charge together
Large molecules

23. Active Transport: Proton Pump

24. Active Transport