2. Regents Biology Passive Transport/Diffusion Cell Membranes & Movement Across Them

3. Regents Biology Concentration Gradients  To understand movement of molecules you have to understand how a concentration gradient works. This is called Passive Transport

4. Regents Biology Characteristics of Passive Transport  Move from HIGH to LOW concentration  No energy required (so not ATP!!!!!) 1. simple diffusion (directly across membrane) 2. facilitated diffusion (with help from protein) 3. osmosis (only water) 3 Types of Passive Transport

5. Regents Biology 1. Simple Diffusion What is Equilibrium? Think food color

6. Regents Biology Pop Quiz - Which way will fat move? inside cell outside cell fat LOW HIGH

7. Regents Biology 2. Facilitated Diffusion  use of a “protein channel”  still no energy (NO ATP!!!!!!) HIGH LOW

8. Regents Biology inside cell outside cell sugar LOW HIGH Pop Quiz - Which way will sugar move?

9. Regents Biology Simple Diffusion vs. Facilitated Diffusion inside cell outside cell lipid inside cell outside cell H2OH2O simple diffusionfacilitated diffusion H2OH2O protein channel

10. Regents Biology 3. Osmosis  Osmosis - diffusion of water from HIGH concentration of “free” water molecules to LOW concentration of “free” water molecules  A “free” water molecule is a water molecule not actively trying to dissolve a solute. What is a free water molecule?

11. Regents Biology Osmosis & “Free water” Test

12. Regents Biology What’s wrong with this picture?

13. Regents Biology Any Questions?