Methods of transport

1. Methods of transport How materials get through the cell membrane

2. Materials must enter/leave the cell through the cell membrane for the cell to survive CELL

3. MOLECULES are ALWAYS in MOTION Molecules are always in motion – Kinetic energy Molecules move faster at higher temperatures Molecules naturally move from areas where they’re more concentrated to where they’re less concentrated along their concentration gradient

4. Concentration Gradient - • A Concentration Gradient is the difference in the concentration of a substance from one location to another.

5. How to Determine the overall direction of movement High Concentration Lower Concentration (in comparison)

6. Diffusion • The movement of molecules from an area where they are more highly concentrated to where they are less concentrated • Results in “dynamic equilibrium”

7. A look at diffusion from the molecular level • Molecules move from where they're highly concentrated to a less concentrated area

8. Diffusion of Chemicals

10. Air Diffusers

11. Insect Pheromones (Sex Scents)

12. Review of Active and Passive Transport • Passive Transport – Molecules move, No cell E Diffusion Facilitated Diffusion Osmosis • Active Transport – Cell uses E Carrier Protein Membrane Pumps Endocytosis (Pinocytosis, Phagocytosis) Exocytosis

13. Passive Transport • Molecules move on their own, cell does not expend energy to transport them across membrane • 3 Forms • Diffusion • Facilitated Diffusion • Osmosis

14. Diffusion of gases between lungs and blood

15. Facilitated (Helper) Diffusion • Movement of material through the cell membrane by a “helper” transport protein that binds specifically to the molecule.

16. Osmosis • Diffusion of water molecules from an area where they are highly concentrated to an area where they are less concentrated through a semipermeable membrane

18. Active Transport - • Movement of materials through the cell membrane which requires the cell to use energy • Three Major Types” • 1. Carrier Protein Membrane Pumps • 2. Endocytosis – “Into the Cell” • 3. Exocytosis – “Out of the Cell”

19. Carrier Protein Membrane Pumps • Can pump molecules from areas of lesser concentration to greater concentration across the cell membrane • Sodium Potassium Pump

20. Endocytosis-Taking in of materials by engulfing them in a vesicle • Phagocytosis – Cell membrane engulfs large particles or whole organisms Ex. WBC’s and Hungry Amoeba! • Pinocytosis – Cell membrane engulfs liquid droplets * Receptor mediated endocytosis – special receptors located in a coated pit in the cell membrane are used to attract and transport materials into cell

21. Video of all Three

22. Exocytosis – release of substances out of cell by fusing vesicle with membrane • Outta Here!

23. Exocytosis in Organisms • Paramecia contractile vacuoles • Contractile Vacuole Closeup

24. Endocytosis and Exocytosis • Coming and Going through the Cell Membrane