1. Bellringer List the two things that make up the cell membrane.
What does it mean to be selectively permeable?

2. From the lab, Order of the items…
Biggest: ?
Smallest: ?
Where do the pores fit in?

3. Sizes of Molecules… Water (H2O) Iodine (I2K) Glucose (C6H12O6)
Food Coloring (~450 atoms)
Starch (~1000 atoms)
So…how big are the pores of the membrane? Make an estimate (with an explanation) on the back side of your questions!!!

6. Fluid Mosaic Model http://www.susanahalpine.com/anim/Life/memb.htm

7. Role of the membrane?
Selective permeability

8. Roles of the membrane proteins
Move stuff across the membrane that can’t get across on its own
Recognition – like nametags
Receptors – trigger cellular responses
Enzymes

9. How does the membrane regulate movement of molecules?
It’s structure dictates!!

10. Cell Transport

12. Cell Membrane Cell Membrane Animation
Made of phospholipids and proteins
Molecules move into and out of a cell through the cell membrane
The cell membrane is selectively permeable
How certain molecules move through the cell is called cell transport
Passive Transport
Active Transport

13. Questions What happens when you spray air freshener or perfume?
What happens when you put food coloring in water?
THIS IS DIFFUSION!!!! Diffusion is also one way things are transported across the cell membrane

14. What is concentration?
Amount of solute in a certain amount of solvent…think about kool-aid…
Solvent – what does the dissolving (liquid)
Solute – what is dissolved in the solvent
Which is more concentrated?

15. Passive Transport
Particles move from high concentration to low concentration
Does NOT require extra cell energy
Includes simple diffusion, osmosis, facilitated diffusion

16. SIMPLE DIFFUSION
Movement of molecules from areas of high concentration to areas of low concentration
Does not require energy (PASSIVE)
Because molecules are in constant, random, motion!
Will diffuse until reaches equilibrium (equal concentrations)
Dynamic equilibrium (still moving!)

17. Diffusion
Dynamic
Equilibrium

18. For lab… To the beaker, add: Water Iodine To the tube, add:
Glucose solution
Starch
To the beaker, add:
Water
Iodine

19. Make a hypothesis…. Will the glucose move? Which way? Why or why not?
Will the iodine move? Which way? Why or why not?
Will the starch move? Which way? Why or why not?

20. Flea Diffusion Analogy

21. Flea Diffusion Analogy

22. Flea Diffusion Analogy

23. Dynamic Equilibrium

24. Simple Diffusion in Cells
Diffusion Animation
Diffusion Across a Membrane

25. PROBLEM BREAK

26. OSMOSIS
The diffusion of water across a membrane from an area of high concentration to low concentration
No energy required (PASSIVE TRANSPORT)
Occurs until reaches DYNAMIC EQUILIBRIUM
Equal concentrations on both sides of the membrane

27. Tonicity of solutions Used to compare the relative concentrations
Hypertonic
solution with a higher concentration of solute
So lower water concentration
Hypotonic
solution with a lower concentration of solute
So higher water concentration
Isotonic
solutions with equal concentrations of solute
Water diffuses from hypotonic solutions to hypertonic solutions!

28.
What About Cells?

29. Cells in Hypertonic Solution
Water moves out of the cell
Cell shrivels
Low Hi

30. Hypotonic Solution Water moves into the cell Cell swells HYPOTONIC
Animal cell – can burst
Plant cell – builds up pressure on cell wall, but rigid cell wall keeps it from bursting
HYPOTONIC Hi Lo

31. Isotonic Solution Water moves in and out of the cell
Cell stays the same size
Dynamic Equilibrium
ISOTONIC

32. Osmosis Animations

33. What happens to slugs in salt?
Dead bodies in the river?

34. FRAYER MODEL BREAK! Draw example define Passive transport
Explain your example
Does it require energy?
Examples

35. Starter Consider the following information:
Water, oxygen, and CO2 all readily move across a membrane
Glucose, proteins and small ions (like Na+ or Cl-) cannot pass on their own
Considering this information, devise a rule that describes what CAN and CANNOT pass through the membrane via SIMPLE DIFFUSION

36. Pumping Water
Some organisms have vacuoles that pump out excess water that enters the cell
Too much water in the cell = vacuole works hard pumping out water!

37. FACILITATED DIFFUSION
Particles move from high concentration to low concentration
No energy needed (PASSIVE)
Cells use proteins to “help”
Transport Proteins
Channel proteins

38. Facilitated Diffusion
FRAYER MODEL BREAK!
Draw example
define
Facilitated Diffusion
Explain your example
Does it require energy?

39. Review passive transport

40. Active Transport
Particles move from low concentration to high concentration (against the concentration gradient)
DOES REQUIRE ENERGY!!
Requires transport proteins
Includes pumps, endocytosis, exocytosis, etc.

41. The sodium-potassium pump
Active Transport = requires energy!
Sodium is pumped out
Potassium is pumped in
Animation

42. Active transport
Examples: Pumping Na+ (sodium ions) out and K+ (potassium ions) in against strong concentration gradients.
Called Na+-K+ Pump

43. Sodium-Potassium Pump
3 Na+ pumped in for every 2 K+ pumped out; creates a membrane potential

44. Pumps
Some animals use salt pumps to maintain a constant concentration of salt in their bodies
This requires energy! ACTIVE TRANSPORT!

45. Pom-Pom Potential
Modeling passive and active transport along a cell membrane in a NERVE CELL
What do nerves do?
How do they do it?

49. Questions How did this activity model passive transport?
How did this activity model active transport?
Why do the membranes “work” to keep the charges on either side of the membrane “balanced”?

50. FRAYER MODEL BREAK! Draw example define Active transport
Explain your example
Does it require energy?
Examples

51. VENN DIAGRAM TIME: MUWAHAHAHAHA
ACTIVE TRANSPORT
FACILITATED DIFFUSION

52. Moving the big stuff…

53. Exocytosis Large substances leave the cell
Vesicle fuses with cell membrane and dumps contents

54. Exocytosis The opposite of endocytosis is exocytosis
Exocytosis The opposite of endocytosis is exocytosis. Large molecules that are manufactured in the cell are released through the cell membrane.
Inside Cell
Cell environment

55. Exocytosis- moving things out.
Moving the “Big Stuff”
Exocytosis- moving things out.
Molecules are moved out of the cell by vesicles that fuse with the plasma membrane.
This is how many hormones are secreted and how nerve cells communicate with one another.

56. Exocytosis
Exocytic vesicle immediately after fusion with plasma membrane.

57. Ponder for a moment…
How does exocytosis fit into PROTEIN SYNTHESIS????

58. Endocytosis Large substances enter the cell
Cell membrane forms a “pit” and wraps around substance
Cell membrane pinches off – forms a vesicle

59. Endocytosis

60. Cell Signaling
Signaling activity
Modeling Nerves…

61. Go to picture 

62. Journal Draw a diagram of what we just did and…
Identify the types of transport going on, as completely as possible (there are TWO you should identify!).
Provide justification for your selection.