Cellular Transport

1. Cellular Transport

3. Outer membrane of cell that controls what comes in and out of the cell. Double layer of lipids Remember…Plasma Membrane

4. Selective Permeability • What does ‘selective’ mean? • Selective Permeability—the cell membrane only allows certain things to pass through, and not others

5. What is found in the plasma membrane? • Cholesterol • Carbohydrates • Proteins

6. Fluid Mosaic Model Video 1:30

7. Febreeze demo What happens when febreeze is sprayed at the front of the room?

8. Food coloring demo

9. Two Types of Cellular Transport: What does it mean to be passive? What about active? 1. Passive Transport & 2. Active Transport

10. 1. Passive Transport - When molecules pass through the cell membrane with NO input of energy The simplest form of passive transport is DIFFUSION Diffusion - movement of molecules from an area of high concentration to an area of low concentration

11. Concentration Gradient • Molecules naturally move from areas of high concentration to areas of low concentration • We call this moving down the concentration gradient

12. Concentration Gradient

13. 1:30

14. oxygen Where is the concentration of oxygen higher? The oxygen molecules will move ________ (up/down) their concentration gradient _____ (into/out of) the cell. The molecules move like this so they can be in equilibrium.

15. The diffusion of water across a selectively permeable membrane is calledOSMOSIS The regulation of water through the plasma membrane is important for the cell to maintain HOMEOSTASIS

16. Sidenote on solutions… • Solution – a homogenous mixture • Solute – The substance being dissolved • Solvent – The substance doing the dissolving (usually water)

17. What controls osmosis? Water will flow to the side of the membrane where the water concentration is lower. Water diffuses until it is in equal concentration on both sides of the membrane. Water is polar. Phospholipids are nonpolar. How can water move through the membrane???

18. The cell part that helps with osmosis: The Contractile Vacuole Collects water and pumps it out of the cell

19. Most cells are surrounded by water solutions and are constantly going through osmosis. There are 3 osmotic states…

20. 1. ISOTONIC– solute concentration outside of the cell is the same as the concentration inside the cell 2. HYPOTONIC – solute concentration is lower in the solution outside the cell than the concentration inside the cell, so water moves INTO the cell 3. HYPERTONIC – solute concentration outside the cell is higher than the concentration inside the cell, so water moves OUT OF the cell

21. 1. Isotonic ?? Is the concentration of water outside the cell the same as the concentration of water inside the cell??? ??Are water molecules moving into and out of the cell???

22. ??? SO WHAT HAPPENS TO THE CELL'S SHAPE ?? 1. Isotonic • Which side of the cell has a higher concentration of water? 2. Is there movement of water across the membrane?

23. 1. Isotonic A plant cell has its normal shape and pressure in an isotonic solution.

24. 2. Hypotonic ?? Where is most of the water located in a hypotonic solution?? Water movement looks like this…. What happens if the cell swells too much ??? It can burst

25. 2. Hypotonic One big difference between plant/animal cells: …So plant cells don’t burst, but animal cells do… How does this apply in the veggie section in a grocery store?

26. ?? Where is most of the water located in a hypertonic solution?? 3. Hypertonic Animal cells in a hypertonic solution shrivel because of decreased pressure in the cells. **Causes the cell to shrink**

27. 3. Hypertonic Plant cells lose pressure as the plasma membrane shrinks away from the cell wall.

28. DO YOU SEE THE DIFFERENCE?

30. Blood cells…

31. Is it hypertonic, hypotonic, or isotonic?

32. Osmosis Review 1:30

34. CARROT TIME • Describe your carrot: How are these carrots different from normal carrots? 2. Consider the salt water solution. What is the solute? The solvent?

35. CARROT TIME 3. Before the carrots were placed in the water, where was the concentration of salt higher – inside the carrot cells, or in the surrounding water? 4. Were the carrots in a hypo-, hyper-, or isotonic solution? How do you know? • Would the same thing happen if we got these carrots from fresh water? • Should we store our carrots in salt water or freshwater?

36. Starch/Iodine Experiment • STARCH • iodine • Iodine is an indicator for starch – means that it will turn purple when it comes into contact with starch • Baggie is like plasma membrane Iodine in water Starch inside bag

37. Starch/Iodine Experiment Make a prediction: • Will starch move out into the water? • Will iodine move into baggie? • Will neither starch nor iodine move? How will we be able to tell if either moves? What does the baggie represent?

38. Starch/Iodine Experiment Which moved – the iodine or the starch? Draw a picture of the cup and baggie and arrows to show which way the diffusion occurred.

40. ?? What molecules would require NO energy to be moved ?? Again…Passive Transport When a cell uses no energyto move particles across a membrane, passive transport occurs. Concentration gradient Plasma membrane

41. ?? What does the word facilitate mean ??

42. Transport proteinshelp some substances move through the plasma membrane.

43. Passive transport by proteins No energy input is required from the cell because molecules are still moving DOWN the concentration gradient. Carrier proteins Concentration gradient Plasma membrane Step 1 Step 2

44. Passive Transport by proteins Passive transport of materials across the membrane using transport proteins is called facilitated diffusion. Concentration gradient Plasma membrane 1:15

45. FACILITATED DIFFUSION 1. Carrier proteins change shape to allow a substance to pass through the plasma membrane. Carrier proteins Concentration gradient Plasma membrane Step 1 Step 2

46. 2. Channel proteins form channels that allow specific molecules to flow through. (do not change shape) Channel proteins Concentration gradient Plasma membrane

48. In facilitated diffusion by a transport protein, the movement is ______ (down/up) the concentration gradient and requires ______ (energy/no energy)input from the cell. Carrier proteins Concentration gradient Plasma membrane Step 1 Step 2

49. Two Types of Cellular Transport: 1. Passive Transport & ☐2. Active Transport

50. ?? What molecules WOULD require energy to be moved ??