Diffusion and Osmosis

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

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

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

Diffusion in your lungs

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…

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

Effect of osmosis on RBC’s

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.

Osmosis and Diffusion