1. CELL MEMBRANE OBJ: Describe the structure and function of the cell membrane according to the fluid mosaic model

2. CELL MEMBRANE- STRUCTURE

3. Plasma Membrane/ Cell membrane A double-layered sheet called a “Lipid Bilayer” Made up of a phosphate head attached to two fatty acid tails ◦ The head interacts with water (hydrophilic) ◦ The tails do not interact with water (hydrophobic)

4. Plasma Membrane/ Cell membrane A double-layered sheet called a “Lipid Bilayer” Flexible, fluid-like structure Made up of a phosphate head attached to two fatty acid tails ◦ The head interacts with water (hydrophilic) ◦ The tails do not interact with water (hydrophobic)

5. Fluid-Mosaic Model Flexible, fluid-like structure Embedded proteins

6. CELL MEMBRANE- FUNCTION

7. Plasma Membrane/ Cell membrane Regulates what enters and leaves the cell Provides protection and support Maintains “homeostasis” for the cell through “selective permeability” ◦ Only certain things are allowed in and out of the cell

8. Plasma Membrane/ Cell membrane Regulates what enters and leaves the cell Provides protection and support Maintains “homeostasis” for the cell through “selective permeability” ◦ Only certain things are allowed in and out of the cell

9. Plasma Membrane/ Cell membrane Regulates what enters and leaves the cell Provides protection and support Maintains “homeostasis” for the cell through “selective permeability” ◦ Only certain things are allowed in and out of the cell

10. Plasma Membrane/ Cell membrane Regulates what enters and leaves the cell Provides protection and support Maintains “homeostasis” for the cell through “selective permeability” ◦ Only certain things are allowed in and out of the cell

11. Plasma Membrane

12. Review Gradient

13. Concentration Gradient High concentration (many of a substance) Low Concentration (few particles of a substance) Difference from one place to another # of sugar molecules Over space

14. MEMBRANE TRANSPORT OBJ: List and explain the main types of membrane transport: Passive, Active, Bulk

15. Background Cells live in an environment of liquid in order to survive The cell membrane must regulate the movement of dissolved substances into and out of the cell in order for the cell to continue to survive

16. Membrane Transport Passive No energy required Active Energy required Bulk Energy required

17. Membrane Transport Passive Diffusion ActiveBulk

18. Diffusion In a solution, the particles are constantly moving The particles move from an area of high concentration to an area of low concentration (that is diffusion)

19. Diffusion Once the concentration is the same throughout, the system is in equilibrium No energy required Diffusion Example

20. Diffusion

21. Why Diffuse?  Cells use diffusion in order to maintain homeostasis  Cells must regulate the movement of particles to control:  temperature  pH  blood glucose levels  water balance

22. Diffusion in Cells ◦ Oxygen ◦ Carbon Dioxide

23. Diffusion http://www.williamsclass.com/SeventhScienceWork/ImagesCellBricks/Diffusion.gif

24. Diffusion

25. OBJ: Define solution, solvent, solute, and be able to determine if a solution is hypertonic, hypotonic,, or isotonic OBJ: Calculate net diffusion or net osmosis

26. Why can’t we drink ocean water??

27. Solution, Solvent, Solute

29. Membrane Transport Passive Diffusion Osmosis ActiveBulk

30. Osmosis Diffusion of water Water is able to pass across the cell membrane very easily

31. Osmosis: Hypertonic ◦ If too much water moves out of a cell, it will shrivel and die

32. Osmosis: Isotonic If water is allowed to move in and out of the cell regularly, it is in equilibrium

33. Osmosis: Hypotonic  If too much water moves into a cell, it will swell and burst

34. Osmosis is Plant Cells

35. Osmosis in Action http://people.eku.edu/ritchisong/osmosis3.gif

38. Membrane Transport Passive Diffusion Osmosis Facilitated Diffusion ActiveBulk

39. Phospholipid Bilayer: Embedded Proteins There are different types of proteins in the bilayer that are responsible for letting things in and out of the cell ◦ Carrier proteins have a carbohydrate arm that pulls stuff in and out of the cell ◦ Channel proteins open a channel in the membrane for stuff to pass through as needed and then close

40. Phospholipid Bilayer: Embedded Proteins There are different types of proteins in the bilayer that are responsible for letting things in and out of the cell ◦ Carrier proteins have a carbohydrate arm that pulls stuff in and out of the cell ◦ Channel proteins open a channel in the membrane for stuff to pass through as needed and then close

41. Phospholipid Bilayer: Embedded Proteins There are different types of proteins in the bilayer that are responsible for letting things in and out of the cell ◦ Carrier proteins have a carbohydrate arm that pulls stuff in and out of the cell ◦ Channel proteins open a channel in the membrane for stuff to pass through as needed and then close

42. Facilitated Diffusion  This process happens when proteins in the membrane allow substances to pass through them constantly (i.e. glucose)  Passive Transport= Cell doesn’t need to use energy

43. Membrane Transport Passive Diffusion Osmosis Facilitated Diffusion ActiveBulk

44. Active Transport  This process is diffusion in reverse  movement of particles from low concentration to high concentration

45. Active Transport  the cell must use its own energy in order to move a substance into it  this usually requires the cell membrane to change shape in some way

47. Membrane Transport Passive Diffusion Osmosis Facilitated Diffusion ActiveBulk

48. Bulk Transport Larger molecules, solid clumps of material Requires energy Requires membrane structures

49. Membrane Transport Passive Diffusion Osmosis Facilitated Diffusion ActiveBulk Endocytosis

50. Endocytosis Taking material into the cell Types of endocytosis ◦ Phagocytosis (eating) ◦ Pinocytosis (drinking)

51. Phagocytosis vs. Pinocytosis

52. Membrane Transport Passive Diffusion Osmosis Facilitated Diffusion ActiveBulk Endocytosis Exocytosis

53. Exocytosis The membrane of the vesicle surrounding substance fuses with cell membrane