There are two main types of transport across cell membranes: passive transport and active transport. Passive transport involves diffusion, osmosis, or facilitated diffusion, which move substances down their concentration gradient without requiring energy. Active transport pumps substances against their gradient by using energy from ATP. Some examples of passive transport are oxygen and carbon dioxide diffusing across membranes and water moving through osmosis, while the sodium-potassium pump is an example of active transport.

1. Passive and Active Transport FOS 3 Infectious Disease Unit

3. Transport Across Membranes Active transport is pumping against the concentration gradient

7. Passive Transport-Diffusion

8. Passive Transport

9. Simple Diffusion Across Bilayers

10. Passive Transort- Osmosis More water Less water

11. Osmosis: Water down Conc. Gradient

12. Tonicity More solute in than out

14. Passive Transport- Facilitated Diffusion

15. Passive Transport- Facilitated Diffusion

18. Active Transport: Sodium-Potassium Pump

20. Active Transport- Electrogenic Pump

21. Active Transport- Cotransport

24. Phagocytosis Pictures

25. Exocytosis