1. Diffusion: Section 6.2 Osmosis: Section 8.1
Diffusion and Osmosis
Diffusion: Section 6.2
Osmosis: Section 8.1

2. Biology /29/ Mrs. Turgeon
DO NOW:
Get out your cell lab worksheet
In your notes: Describe one difference between an animal cell and a plant cell.
AGENDA:
Finish part F of cell lab as a group
Take notes on diffusion and osmosis
REMINDERS:
Science Club today after school, room 312!
Science Fair judges still needed

3. Objective
SWBAT explain how molecules are transported across the cell membrane.

4. Diffusion
The net movement of molecules from an area of higher concentration to an area of lower concentration.

5. Diffusion
Diffusion results because of the random movement of particles.
Three key factors: concentration, temperature, pressure affect the rate of diffusion.
Equilibrium is reached when there is an even distribution of solute molecules 2 3 1 4
(water)

6. The diffusion of water across a selectively permeable membrane.
Osmosis
The diffusion of water across a selectively permeable membrane.

7. Osmosis
In a cell, water always moves to reach an equal concentration on both sides of the cell membrane.

8. Osmosis
The direction of osmosis depends on relative concentrations of dissolved particles on the two sides of the membrane.

9. *water diffuses into and out of the cell at equal rates.
Direction of Osmosis
Isotonic Solution
concentration of dissolved particles outside and inside the cell are equal.
there will be no net movement* of water.
*water diffuses into and out of the cell at equal rates.

10. Direction of Osmosis Hyptertonic Solution
concentration of dissolved particles outside the cell is higher than in the cytosol.
water will diffuse out of the cell.

11. Direction of Osmosis Hypotonic Solution
concentration of dissolved particles outside the cell is lower than in the cytosol.
water will diffuse in to the cell.

13. How Cells deal with Osmosis
Chapter 5
How Cells deal with Osmosis
To remain alive, cells must compensate for the water that enters the cell in hypotonic environments and leaves the cell in hypertonic environments.

14. Passive Transport Movement of molecules across the cell membrane
Does NOT require energy
Examples: diffusion and osmosis

15. Facilitated Diffusion
Passive transport of materials across the cell membrane using transport proteins.
Examples:
Carrier Proteins
Ion Channels

16. Facilitated Diffusion
Chapter 5
Facilitated Diffusion

17. Chapter 5
Active Transport
Movement of particles across the cell membrane against the concentration gradient
(lower concentration  higher concentration)
Requires ENERGY!!!
Example:
Carrier proteins, endocytosis, exocytosis

18. Active Transport Endocytosis Chapter 5
Cells ingest external materials by folding around them and forming a pouch.
Engulfs bacteria, food etc.

19. Active Transport Exocytosis Chapter 5
Excretion of materials from a cell.
Expels wastes, hormones etc.