Cellular Transport: Movement of substances into and out of a cell

1. Cellular Transport:Movement of substances into and out of a cell

2. BIG Ideas in Biology 4. Through a variety of mechanisms organisms seek to maintain a biological balance between their internal and external environments Homeostasis

3. Homeostasis= homeo-/homo- =same -stasis=stay • Expend energy to maintain internal conditions • Ex: If we all ran 5 miles on the track right now… • Body temp= 37oC or 98.6oF • Heart Rate

4. All cells MUST exist in a liquid environment

5. Brownian Motion/Movement: • the random movement of microscopic particles suspended in a fluid Particles MOVE!!!

6. Cell MembraneWhat’s inside?What’s outside? LIQUID!!!! LIQUID!!!!

7. Extracellular Fluid: Cells watery environment Outside Inside Intracellular Fluid: Cells liquid center/cytoplasm

8. Cell Membrane • Not rigid like… BUT… Fluid like…

9. Cell Membrane Selectively Permeable -Semi-permeable -Only lets specific selected items into or out of the cell

10. Fluid Mosaic Model -model of the structure of a cell membrane -discovered in 1972 by Singer and Nicolson

11. Cell Membrane Which type of lipid forms this structure? PHOSPHOLIPID A B C Polar A= Hydrophillic or water-loving B= Protein Channel (“secret passage way”) C= Hydrophobic or water-fearing NonPolar

12. Fluid Mosaic Model Hydrophobic-Non-Polar- (water fearing) Hydrophilic -Polar- (water loving)

14. Fluid Mosaic Model Why do we needcholesterolin our diet? Help make membranes!!!!

15. Components of the Cell Membrane Carbohydrate chains Used for cell recognition Phospholipidbilayer Type of lipid Contain pores/openings Proteins - receptor proteins - transporting proteins - adhesion proteins

16. Several types of proteins embedded in the bilayer: 1. Receptor proteins: act as a docking area for items to attach to like hormones

17. 2. Transporting proteins: -transports items across the bilayer

18. 3. Adhesion Proteins: -project outward from bilayer and help cells within a tissue to stick together

19. Cell Transport is needed for 2 reasons… • Get the INGREDIENTS for Photosynthesis and Cell Respiration 2. Get rid of WASTE products Carbon Dioxide and water O2 Oxygen and water CO2

20. Two Types of Cell Transport • Passive Transport: • Movement across the cell membrane (in and out of the cell) that does NOT require energy • Active Transport: • Movement across the cell membrane that NEEDS ENERGY

21. Passive Transport – Perfume Analogy • Raise your hand in the air • Mrs. Red will spray something in the front of the room • Put your hand down when you can smell it

22. All Molecules have motion: • Solid • small amount of energy & little movement (just vibrating) • Liquid • molecules gain some energy & some movement • Gas • molecules gain a lot of energy & a lot of rapid movement

24. Passive Transport Diffusion: • Random movement of molecules from an area of HIGHconcentration to an area of low concentration • RESULTS = Dynamic Equilibrium

25. Balloons • Why process does this represent? • What does the balloon represent?

26. Passive Transport • Concentration gradient: • Difference in concentration of a substance across a space • MUST EXIST for passive transport to occur • Equilibrium: • Condition when concentration of a substance is equal throughout a space • Molecules are still MOVING

27. equilibrium High low

30. Passive Transport • What diffuses across a cell membrane? • Small, uncharged molecules • Ex: O2 & CO2 Zooming in…

31. Example of diffusion in our body:

32. The rate of diffusion can be increased by: 1. Increase in temperature 2. Increase in surface area 3. Stirring or shaking

33. SIMPLE DIFFUSION VIDEO

34. 3 Types of Diffusion (Passive Transport) • Simple Diffusion • Osmosis: • AKA diffusion of WATER • Water moves from area of HIGH concentration to an area of low concentration • Facilitated Diffusion

35. Passive Transport: Osmosis • When does Osmosis stop? • Equilibrium…Osmotic Balance (Homeostasis) equilibrium

38. Solvent: Substance doing the dissolving (water) Solute: Substance being dissolved (salt) Solution: Created when the solute DISSOLVES in the solvent (salt water)

39. The direction of Osmosisis controlled by the concentration of the solution located Inside AND Outside the cell **Remember water moves from a HIGHconcentration to a lowconcentration** H L H L

40. 3 types of solutions/environments: LOW • Hypotonic solution: • concentration of solute molecules Outsidethe cell is lower than the concentration of solute molecules Insidethe cell

41. Where will water move then? Why? Hypotonic Environment: Where is there more water? 98% water 2% solute Water enters the cell Turgor pressureincreases Cell swells in size=cytolysis 96% water 4% solute

42. 3 types of solutions/environments: EQUAL • Isotonic solution: • concentration of solute molecules Outsidethe cell is equal t0 the concentration of solute molecules Insidethe cell

43. Where will water move then? Why? Isotonic Environment: Water enters and leaves the cell at an equal rate Turgor pressure remains constant Cell remains the same in size= osmotic balance (homeostasis) Where is there more water? 96% water 4% solute 96% water 4% solute

44. 3 types of solutions/environments: HIGH • Hypertonic solution: • concentration of solute molecules Outsidethe cell is HIGHERthan the concentration of solute molecules Insidethe cell

45. Hypertonic Environment: Where will water move then? Why? 94% water 6% solute Water leaves the cell Turgor pressure decreases Cell decreases in size= plasmolysis Where is there more water? 96% water 4% solute

47. Hypotonic Isotonic Hypertonic

48. Osmosis Affects Plants and Animals! Animals Plants

49. Elodea

50. OSMOSIS Video