1. Honors Biology Cellular Transport

2. Diffusion The net movement of particles from an area of high concentration to an area of low concentration

3. High concentrationLow concentration Equal distribution

4. Diffusion Movement goes with the concentration gradient –From areas of high concentration to areas of low concentration

5. Osmosis Diffusion of water through a selectively permeable membrane Goes with the concentration gradient

6. Osmosis Weak solution Strong solution WATER (Lots of water molecules) (Few water molecules)

7. Selectively permeable membrane Weak solution Strong solution Membrane allows water to pass but not solutes Solutions with equal concentrations

8. Osmosis Special terms for referring to strong or weak solutions

9. Osmosis –Isotonic: two solutions with equal concentrations of solutes

10. Osmosis Special terms for referring to strong or weak solutions –Isotonic: two solutions with equal concentrations of solutes –Hypertonic: solution with high concentration of solutes (strong solution)

11. Osmosis Special terms for referring to strong or weak solutions –Isotonic: two solutions with equal concentrations of solutes –Hypertonic: solution with high concentration of solutes (strong solution) –Hypotonic: solution with low concentration of solutes (weak solution)

12. Osmosis HypotonicHypertonic WATER

13. When does diffusion/osmosis stop? Never! When it reaches a homeostatic balance equal numbers of molecules are moving in both directions !

14. Turgor Pressure The pressure inside a cell Maintained via osmosis

15. Turgor Pressure Plasmolysis

16. Contractile Vacuoles Lysis

17. Cellular Transport Passive: goes with concentration gradient Active: goes against concentration gradient

18. Cellular Transport Passive Active Endo- and Exocytosis

19. Cellular Transport Passive –Simple diffusion through the lipid bilayer –Simple diffusion through an ion channel –Facilitated diffusion Active Endo- and Exocytosis

20. Passive Transport Simple diffusion through the lipid bilayer Simple diffusion through an ion channel Facilitated diffusion

21. Simple diffusion through the lipid bilayer Small, non-polar molecules –O 2 and CO 2 Osmosis Goes with concentration gradient

22. Passive Transport Simple diffusion through the lipid bilayer Simple diffusion through an ion channel Facilitated diffusion

23. Simple diffusion through an ion channel Ions are highly polar and cannot pass through the lipid bilayer Ions are critical to cell functioning –Na +, K +, Ca +, and Cl -

24. Simple diffusion through an ion channel Pass readily through a water-filled pore formed by an integral membrane protein

25. Simple diffusion through an ion channel Movement is bi-directional Channels are specialized for a single ion Goes with concentration gradient

26. Passive Transport Simple diffusion through the lipid bilayer Simple diffusion through an ion channel Facilitated diffusion

27. Facilitated Diffusion Diffusion is aided by a carrier protein (integral membrane protein)

28. Facilitated Diffusion Molecule to be transported physically binds to the carrier protein on one side of the membrane Protein undergoes a conformational change that does not require energy Molecule is released on the other side of the membrane

29. Facilitated Diffusion Molecule is attracted to a specific carrier protein

30. Facilitated Diffusion Molecule binds to carrier protein

31. Facilitated Diffusion Carrier protein undergoes conformational change and releases molecule on other side of membrane

32. Facilitated Diffusion Movement is bi-directional Carrier proteins are specialized for a single ion or molecule Goes with concentration gradient Passive process

33. Cellular Transport Passive Active Endo- and Exocytosis

34. Active Transport Similar to facilitated diffusion –Molecule to be transported physically binds to the carrier protein on one side of the membrane and is released on the other side of the membrane via a shape change of the protein

35. Active Transport Goes against concentration gradient Requires energy input from the cell

36. Active Transport

38. Bi-directional Carrier proteins are specialized to move a single substance

39. Active Transport Sodium-Potassium (Na-K) Pump Cotransport Countertransport Proton Pump (Next chapter)

40. Na + - K + Pump Cell needs low Na + and high K + relative to external environment Ions are “pumped” into and out of the cell via an integral membrane protein Na + concentration becomes form of stored energy for cotransport

41. Cotransport Na + is pumped into cell with concentration gradient Simultaneously sugar or amino acid is pumped into cell against concentration gradient

42. Countertransport Na + is pumped into cell with the concentration gradient Ca + or H + is pumped into cell against the concentration gradient

44. Cellular Transport Passive Active Endo- and Exocytosis

45. Used to move large amounts of materials into or out of a cell quickly Requires energy

46. Endocytosis Cell consumes large molecules or other cells Cytoskeleton extends plasma membrane outward toward particle, encircles the it, and contracts membrane back inwards, engulfing particle

47. Endocytosis 2 types –Phagocytosis –Pinocytosis

48. Endocytosis Phagocytosis: “Cell eating” –Cell takes in solid particles

49. Endocytosis Pinocytosis: “Cell drinking” –Cell takes in liquid materials

50. Exocytosis Cell excretes large wastes Mechanism for releasing hormones