1. The Cell Membrane and Transport

2. Phosphate Head (Polar): “Likes Water” Lipid Tail (Non-Polar): “Does Not Like Water”

3. The Plasma Membrane - S.J. Singer proposed the Fluid Mosaic Model to describe the cell membrane The membrane is semipermeable (imagine a fence or screen door) The phospholipid bilayer

4. Jobs of the Cell Membrane Isolate the cytoplasm from the external environment Regulate the exchange of substances Communicate with other cells Identification

5. 1. The plasma membrane is a phospholipid bilayer with embedded proteins.

6. Phospholipids have both hydrophilic and hydrophobic regions; nonpolar tails (hydrophobic) are directed inward, polar heads (hydrophilic) are directed outward to face both extracellular and intracellular fluid

7. The proteins form a mosaic pattern on the membrane. Cholesterol - stiffens and strengthens the membrane. Glycolipids – are protective and assist in various functions. Glycoproteins - have an attached carbohydrate chain of sugar that projects externally

9. Proteins embedded in membrane serve different functions Transport Proteins - regulate movement of substances

10. Channel Proteins- form small openings for molecules to diffuse Carrier Proteins- binding site on protein surface "grabs" certain molecules and pulls them into the cell Gated Channels - similar to carrier proteins, not always "open" Receptor Proteins - molecular triggers that set off cell responses (such as release of hormones or opening of gated-channel proteins), binding site Recognition Proteins - ID tags, to identify cells to the body's immune system Enzymatic Proteins – carry out specific reactions

11. Figure 5.6 Passive Transport (no energy) Simple Diffusion - water, oxygen and other molecules move from areas of high concentration to areas of low concentration, down a concentration gradient! *Trying to reach equilibrium: When dispersion of molecules is equal throughout.

12. Facilitated Transport (Diffusion) - diffusion that is assisted by proteins (channel or carrier proteins) Simple Diffusion: Ex. Oxygen & Carbon Channel Proteins: Ex. Water & other polar molecules Facilitated Diffusion: Ex. Glucose

13. Steps Involved With A Carrier Protein

14. Example: Diffusion within the body. *Diffusion is how oxygen enters our bloodstream.*

15. Example of diffusion.. A.Food coloring in water B.Smelling lunch in other parts of building C.Water moving into a dry sponge. D.All are diffusion E.None are diffusion Response Grid Countdown 20

16. Diffusion is passive because A.Moves from low to high concentration B.Reaches equilibrium C.Does not require energy D.Does require energy Response Grid Countdown 20

17. OSMOSIS Osmosis - diffusion of WATER from high concentration to low concentration. Turgor pressure occurs in plants cells as their central vacuoles fill with water. H 2 0 moves High to Low Concentration! Simple rule of osmosis

18. Figure 5.8a Within the cell, there is a higher concentration of solute (salt) This causes water to be "sucked" into the tube. The solution in the beaker is HYPOTONIC

19. Figure 5.8c Within the cell, there is a lower concentration of solute (salt) This causes water to be "sucked" out into the beaker The solution in the beaker is HYPERTONIC

20. Figure 5.8b

21. Isotonic - no net movement Hypotonic -When solute concentration is lower outside than it is inside the cell– water moves into the cell, cell could burst Hypertonic - When solute concentration is higher outside than it is inside the cell--water moves out of the cell, cell shrinks

22. Figure 5.9

23. Passive Transport: requires no energy (diffusion, osmosis) Active Transport: requires the cell to use energy (ATP)

24. Sodium-Potassium Pump - pumps out 3 sodiums for every 2 potassium's taken in against gradient A huge amount of energy in our bodies is used to power this pump and prevent sodium from building up within our cells. What would happen if you had too much sodium in your cells?

25. SODIUM POTASSIUM PUMP

26. Active Transport - involves moving molecules "uphill" AGAINST the concentration gradient, which requires energy Endocytosis - taking substances into the cell (pinocytosis for water, phagocytosis for solids)

27. Figure 5.12 Exocytosis: pushing substances out of the cell, such as the removal of waste

28. Figure 5.13ca Receptor-Mediated Endocytosis: occurs when specific receptor helps substances across the membrane.

30. Membrane Permeability  Transport Across Membrane *Selectively or Differentially permeable – some things can cross, not others What things can pass? What cannot pass?

32. Figure 5.4a

33. Figure 5.4b

34. Figure 5.4c

35. Figure 5.4e

36. Figure 5.4d

37. Mini Labs and Demos 1. Place a baggie full of start in a beaker that has iodine (an indicator for starch). Observe what happens. 2. Create a wet mount of elodea (anacharis) and observe what happens to the cells when you add salt water. 3. Observe what happens when food coloring is placed in a beaker of water. How does the process change if the water is heated first? *There is an AP Lab on diffusion and osmosis that we will be doing later.

38. Figure 5.14bb Tight Junction

39. Figure 5.14cb Gap Junction

40. Figure 5.14ab Desmosomes (anchors)

41. Pg 99a

42. Pg 99b

43. Pg 100

44. Pg 85

45. Pg 86