Topic: Cells Aim: How does the cell mebrane work?

1. Topic: Cells Aim: How does the cell mebrane work?

2. Cell Membrane

4. Also known as the Plasma Membrane • Surrounds the cell

5. Semi-permeable • Selectively permeable –”chooses” what enters and leaves • MOST OF TIME BASED ON SIZE OF MOLECULE

6. Made of a bilayer (2) of lipids AND proteins

7. Concentration Gradient Difference in concentration between the 2 areas

8. Cells transport materials by the following processes 1. PASSIVE TRANSPORT When particles move from an area of high concentration to an area of low concentration

9. Molecules Move with the gradient no energy needed

10. 2. ACTIVE TRANSPORT When particles move from an area of low concentration to an area of high concentration

11. Molecules Moveagainst the gradient energy required HIGH LOW

12. Passive Transport 2 Types 1. Diffusion 2. Osmosis

13. No energy • High  low

14. Diffusion Substances other than water that move from HIGH LOW

15. DIFFUSION LOW HIGH

17. Molecules eventually stop moving when….. Equilibrium is reached no further change in conc. occurs & both sides are equal

19. Diffusion through a membrane Cell membrane Outside cell Inside cell

20. Diffusion through a membrane Cell membrane diffusion Outside cell Inside cell

21. Diffusion through a membrane Cell membrane Outside cell Inside cell EQUILIBRIUM

23. Do Now: Identify this process by name and explain why you chose that process.

24. Osmosis DIFFUSION OF WATER INTO AND OUT OF THE CELL

25. Movement of WATER from HIGHLOW Concentration • With the Conc. Gradient • NO ENERGY NEEDED!

27. Osmosis Cell membrane Outside cell Inside cell High conc. of water molecules. Low conc. of water molecules.

28. Osmosis Cell membrane OSMOSIS Outside cell Inside cell High conc. of water molecules. Low conc. of water molecules.

29. Osmosis Cell membrane OSMOSIS Outside cell Inside cell EQUILIBRIUM. Equal water concentration on each side.

30. What happens when you place a cell in: 1. Salt water: CELL SHRINKS bc osmosis occurs  water moves out of cell

32. Red blood cells that were placed in a salt solution

33. **Plant cells don’t shrink b/c of rigid cell wall  cell membrane pulls away from cell wall**

35. Onion Skin Cells

36. 2. Distilled/ pure water • Cell fills up with water bc water moves into cell due to osmosis

37. Animal cells = • swell & burst

38. Plant cells = • swell, but do not burst b/c of their cell wall

39. Red blood cell in distilled water about to burst

41. Animal Cells Same amount of water inside and outside the cell Salt solution Distilled water

42. Plant Cells Distilled water Salt solution Same amount of water inside and outside the cell

43. TOPIC: CELLS In your own words describe the similarities and differences of diffusion and osmosis. The similarities of diffusion and osmosis are ______________ _______________ The differences of diffusion and osmosis are ______ _______________ _______________ DO NOW: AIM: HOW DOES ACTIVE TRANSPORT OCCUR?

44. Active Transport Movement of molecules from an area of low concentration to an area of high concentration Against the Conc. Gradient ENERGY IS NEEDED!

45. L L H H

46. CELL MEMBRANE PROTEIN LOW (energy)

49. What process is each cell carrying out? Passive Transport Active Transport

50. Endocytosis Taking substances into cell by surrounding it with the cell membrane How some uni-cellular organisms take in food Form of ACTIVE TRANSPORT (energy required)