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 Move against the gradient
energy required
HIGH
LOW

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

13. No energy
High  low

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

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

29. Osmosis OSMOSIS EQUILIBRIUM. Equal water concentration on each side.
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. Same amount of water inside and outside the cell
Animal Cells
Same amount of water inside and outside the cell
Salt solution
Distilled water

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

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

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

50. 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)
Endocytosis

51. Cell membrane folds in causing a vesicle to form

52. Exocytosis Vesicle fuses with cell membrane causing the
materials inside to be released
Also a form of Active Transport