2. Cellular Transport

3. Passive Transport Movement of molecules across the membrane No energy needed High to low concentration Ex: diffusion, osmosis, facilitated diffusion

4. Diffusion Robert Brown – Scottish scientist in 1827 discovered Brownian motion. ▫Random movement of molecules Movement from high to low concentration.

5. Diffusion Affected by: ▫Concentration – the higher the concentration, the faster it diffuses; the lower the concentration, the slower it diffuses. ▫Size and type of molecule ▫Temperature – the warmer the temperature, the faster it diffuses; the colder the temperature, the slower it diffuses.

6. Dynamic Equilibrium Reached when movement in the cell is equal to the cell balance

7. Osmosis Movement of water molecules through a selectively permeable membrane Types of diffusion ▫Isotonic solution – movement same in and out ▫Hypotonic solution – gain turgor pressure, swells and may burst ▫Hypertonic solution – loss of turgor pressure, water leaves cell, shrinkage occurs  Plasmolysis (cell wilts)

8. Diffusion Process IN food carbohydrates sugars, proteins amino acids lipids salts, O 2, H 2 O IN OUT waste ammonia salts CO 2 H2OH2O products

9. Facilitated Diffusion Use Transport Proteins that span the cell membrane Transport proteins ▫Channel proteins: provides tube-like opening in the plasma membrane through which particles can diffuse ▫Carrier Protein: changes shape “The Bouncer”

10. Osmosis ► http://www.ias.ac.in/initiat/sci_ed/resources/ch emistry/osmosis3.gif

12. Osmosis Related to Red Blood Cells ► http://www.ndpteachers.org/perit/osmosis2.gif

13. Active Transport Requires additional energy and transport proteins Low concentration to high concentration ATP high low

14. Extra Terms Endocytosis – large molecules enter cell Exocytosis – large molecules exit the cell (waste) Exocytosis  Video Sample

15. Transport Video