1. Diffusion and Osmosis

2. Why is diffusion and Osmosis important?
Quick review:
What do all of our cells need?
Oxygen
Water
Nutrients
Get rid of CO2
What is a selectively permeable membrane?
Membrane which allows certain materials to pass through while stopping other materials

3. Diffusion
Movement of a substance from a high concentration to a lower concentration
This occurs until the substance has reached equilibrium (balanced)
Diffusion

4. Diffusion (cont)
Each and every one of our cells need to take in and release a lot of different material.
This happens through diffusion.
High amount of O2 outside of cell
Low amount of O2 inside the cell
O2 moves across selectively permeable membrane

5. Diffusion in your lungs

6. Osmosis This is a type of diffusion. The only difference is:
Osmosis is ONLY the movement of WATER across a selectively permeable membrane.
Usually water isn’t pure. It’s not 100% water molecules (H20).
It usually contains other contaminants like metals, flouride, iron, bacteria, salt, etc…

7. Osmosis (cont)
Distilled water is purified water without salts and impurities.
Cannot find it in nature.
Should not drink distilled water. Why?
If you’re drinking pure 100% water,
your cells will take in water due to osmosis, and rupture. It’s possible you will have blood in your urine.
70% water
(cell)
100% pure water

8. Effect of osmosis on RBC’s

9. Effect of Temperature on diffusion
Colder temperatures decrease diffusion
Molecules are moving slower
Warmer temperatures increase diffusion
Molecules are moving faster
Moral of the story:
If you’re going to fart, fart in a cold room rather than a hot room.
The smell won’t diffuse as fast and stink up the room.

10. Osmosis and Diffusion