Cell Transport: Moving molecules in and out of the cell

1. Cell Transport: Moving molecules in and out of the cell

3. Label the following parts of your diagram • Plasma membrane (about 6-7 nm wide) • A. Phospholipids (A1 is the phosphate head, A2 is the fatty acid tail) • F, G. Proteins • Some have channels (G) • D. Carbohydrate • Glycoproteins (C) – this is a molecule where a carb is attached to a protein • Glycolipids (B) • The is a molecule where a carb is attached to a phospholipid • E. Cholesterol

4. Plasma membrane Phospholipidbilayer that surrounds all cells and certain organelles within the cell

5. Phospholipids Hydrophilic Phosphate head Hydrophobic Fatty acid Tails

6. In water what will happen?

7. Water on outside of cell

8. Water on outside of cell Also Water on Inside of cell

9. Double Layer Allows: All hydrophobic parts to be away from water All hydrophilic parts to be near water

10. Membranes are MORE than just phospholipids

11. Key components

12. The role of membrane components • Proteins • Act as transport for some larger molecules • Increase contact with the water • Cholesterol • Keeps the membrane “tight” and makes it less permeable to small molecules

13. The role of membrane components • Carbohydrates • Chains act as “ID” tags (made in the SER (carbs) and attached to proteins and packaged in the Golgi)

14. Review of vocabulary • Homeostasis • Maintenance of the cells internal conditions (pH, water, temperature, size, etc)

15. Review of Vocabulary • Solution • Homogeneous mixture • Solute: what is dissolved (in living things this can be glucose, amino acids, salts, etc) • Solvent: What is the dissolver (in living things, this is water)

16. What needs to enter and leave the cell • What needs to enter the cell (what goes IN)? • Gases like O2, N2, CO2 • Ions • Small polar molecules (water) • Polar molecules (glucose, amino acids, fatty acids, nucleotides) • What needs to leave the cell (OUT)? • excess H2O, CO2, other waste products, glucose (in a leaf cell or in an intestinal cell), ions, large polar molecules (proteins) , N2, O2 (in the case of plant cells)

17. Selective Permeability The membrane allows some, but not all molecules into the cell The membrane DOES NOT necessarily protect the cell from “Bad things”! http://www.youtube.com/watch?v=Pt4Ch-YW-xs

18. Polar molecules like Glucose and water Not everything that passes through the phospholipids of the membrane are good!

19. What passes through the phospholipidbilayer? • Gases • Oxygen (O2) and nitrogen (N2) and CO2 • Sometimes things that aren’t good for us!!!!

20. What types require a membrane protein Look at the diagram…what cannot go through the membrane but is required by cells?

21. What do cells need that CAN’T pass through the phospholipidbilayer? Small polar molecules (H2O) Ions (Na+, Cl-, K+, Ca++) Large polar molecules (Sugars, Amino Acids) How do these things get into the cell????

22. These must go through proteins to get in • Need the proteins to “help” (facilitate) moving the molecule into the cell or out of the cell • http://www.d.umn.edu/~sdowning/Membranes/diffusionanimation.html • http://www.youtube.com/watch?v=NC8pIzNzqrc

23. Passive Transport Requires no energy; molecules move from an area of high concentration to an area of low concentration. Molecules “roll down the hill” to spread out

24. Three types of Passive Transport Diffusion Facilitated Diffusion Osmosis

25. Diffusion Movement of solutes from areas of high concentration to areas of low concentration until concentrations are equal Move due to a concentration gradient. Concentration Gradient = differences in Concentration

26. Diffusion – Do we need a membrane? High Conc. Low Conc. Can occur without a membrane

27. Think of it as “spreading out”

28. Progression of Liquid Diffusion http://www.youtube.com/watch?v=aVc_LEuiZ-4

29. High Conc. Low Conc. The dye moves from an area of HIGH CONCENTRATION to an area of LOW concentration (of the dye) ?

30. FacilitationFacilitated Diffusion movement of solute from high concentration to low concentration …………..BUT requires transport protein …………..WHY? to move molecule that are too big or polar to get through the phospholipidbilayer EXAMPLE: GLUCOSE too big for the PL membrane

31. Facilitated Diffusion compared to Diffusion One requires “help” or facilitation to get through the membrane

32. Osmosis A Passive Process where water moves across a cell membrane from an area that is hypotonic (lots of water, little solute) to an area that is hypertonic (little water, lots of solute). THE SOLUTE DOES NOT MOVE!!!! PICTURE: Think of water as trying to dilute the concentrated side to make the concentrations equal (it can only do this if water moves, but not the solute!). Eventually both sides are “medium” Weak Iced Tea Strong Iced Tea

33. Osmosis http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_osmosis_works.html

34. Osmosis and Tonicity • Water will move from an area of high concentration of WATER (low solute) to low concentration of water ( high solute) • Tonicity is concerned with the concentration of solute • Water moves from LOW tonicity (high water) to HIGH tonicity (low water)

35. A B A B

36. TONICITY • Term used to compare the concentrations (of solute) of two solutions • The tonicity will determine in WHICH DIRECTION the water flows Hypotonic 3 Conditions Isotonic Hypertonic

37. Terms used to describe tonicity The solution with the higher concentration is called Hypertonic. The solution with the lower concentration is called Hypotonic If the concentrations are equal, they are called Isotonic

38. Which of the solutions is Hypertonic (as compared to the other)? 10% Salt Solution 20% Salt Solution

39. Inside is Hypertonic

40. Which is hypertonic? 20% Salt Solution 10% Salt Solution

41. Outside is Hypertonic ?

42. Isotonic: 20% Salt Solution 20% Salt Solution

43. Isotonic

44. Comparing Cell types chart Cytolysis Crenation

45. Plasmolysis Vs. Turgidity in Plant cells - Turgor pressure: Pressure that the water INSIDE the cell puts on the cell wall. Supports plant

47. http://highered.mcgraw-hill.com/sites/9834092339/student_view0/chapter38/animation_-_osmosis.htmlhttp://highered.mcgraw-hill.com/sites/9834092339/student_view0/chapter38/animation_-_osmosis.html

48. A B A B

49. Active Transport Cell must use energy to force molecules to move across the membrane from a low concentration to a high concentration. Usually used to move ion and since ions can not go through the phospholipids requires a transport protein . Usually moving from a low to high concentration

50. Active Transport: