1. Movement of molecules across cell membrane

2. Movement of molecules across cell membrane
This includes the following four transport phenomena 1-Diffusion 2-Mediated-transport system 3-Osmosis 4-Endocytosis & Exocytosis

3. I-Diffusion

4. Definitions
1- Diffusion 2- Flux 3- Net flux 4-Diffusion equilibrium 5- Zero net flux

5. Zero net flux ?
When does this occur? Is the cell still able to live ?

6. Notes:
Nonpolar (Non-ionized) molecules diffuse through the lipid portion of the membrane much more rapidly than do polar molecules.

7. II- Mediated-transport system
Example : Mineral ions
Mineral ions diffuse across membranes by passing through ion channels formed by integral membrane proteins (transporter).

8. The transporter of molecules or ions
Changes in the conformation of the transporter moves the binding site to the opposite side of the membrane.

9. A- Facilitated diffusion ( (Passive transport
Is a mediated-transport process that moves molecules form higher to lower concentration across a membrane by means of transporter. 1-This process does not require a metabolic energy 2- this process occurs continuously with or without bound solute.

10. B- Active transport

11. What is this organelle? Function?

12. Is it real?
Thank you