1. The Cell in its Environment 6 th Grade Text, Chapter 5-1

2. CELL MEMBRANE “THE DOOR MAN” The cell membrane is selectively permeable. That is… it regulates which materials can enter and leave the cell. Examples: –Permeable to water, oxygen, and carbon dioxide –Not permeable to large molecules and salts Image: www.answers.com/topic/semipermeablewww.answers.com/topic/semipermeable

3. What is SELECTIVE PERMEABILITY?SELECTIVE PERMEABILITY feature and a function of the cell membrane essential to maintain equilibrium by regulating the passage of some substances Some substances can pass through but other substances cannot Example: Restaurants and Malls –“No shoes, no shirt, no service.”

4. cell transportationcell transportation * Substances can move in and out of a cell in 2 ways: 1.Passive transport Diffusion Osmosis 2.Active transport Endocitosis exocitosis

5. Passive transportPassive transport * A molecule that crosses the membrane by moving down without using energy Diffusion Osmosis

6. DIFFUSION Process by which molecules move from an area of higher concentration to an area of lower concentration. Concentration: –The amount of a given substance in a given volume. –Ex: How much sugar is in your glass of iced tea.

7. What causes diffusion? Over time the molecules will spread out until they are evenly spread over an area or reach equilibrium.

8. OSMOSIS Is a process in which the water molecules moves from an area of higher concentration of water to an area of lower concentration of water The water molecules moving through a selectively permeable membrane until equilibrium has been reached

9. Is osmosis important Yes it is important because cells cannot function properly with out water!!!!!

10. Cell environment Solutions and osmosis a red blood cell is put in a glass of distilled water (all water with no salt or sugar in it) also known as hypotonic solution. Because there is a higher concentration of water outside the cell, water enters the cell by OSMOSIS. In this case too much water enters and the cell swells to the point of bursting open. In the end pieces of cell membrane are left in the water. http://www.usd.edu/~bgoodman/Osmos.htm

11. Solution= solute + solvent Solute a substance dissolved in another substance NaCl Solvent A liquid in which substances are dissolved H 2 O

12. solutions! Hypertonic solution that has more solutes than the cytoplasm of the cell. If water molecules continue to diffuse out of the cell, it will cause the cell to shrink.

13. Green Machine Elodea Distillated water Hypotonic solution H 2 O + NaCl Hypertonic solution

14. Green Machine Elodea Distillated water NaCl Hypotonic solution H 2 O + NaCl Hypertonic solution

15. solutions!solutions! * Hypotonic refers to a solution that contains less solute (more water) compared to the cytoplasm of the cell. If the solution surrounding the cell is hypotonic osmosis causes water to have a net flow into the cell, thus, resulting in the swelling and expansion of the cell.

16. Isotonic Pertaining to a solution that has the same amount of solutes that cytoplasm of the cell. The water molecules will stay balance

17. DIFFUSION DIFFUSION BP IN RED CELLS: OXYGEN There are a lot more oxygen molecules outside of the cell than there are in the cell. That is, there is a higher concentration of oxygen molecules outside of the cell, and a lower concentration of oxygen molecules inside the cell. This causes oxygen molecules to move into the cell. Passive transport BPPassive transport

18. Osmosis & Red Blood CellsRed Blood Cells Image: http://academic.brooklyn.cuny.edu/biology/bio4fv/page Salt Water: Water moves out of the cell and into the surroundings causing the cell to shrink Normal Red Blood Cell Distilled Water: Water moves into the cell because there is more salt in the cell that there is water.

19. How does it works for unicellular organism?

20. Questions: Which way will the oxygen molecules move? Into the cell Why will the oxygen molecules move into the cell? Because during diffusion the oxygen molecules will move from an area of high concentration to an area of low concentration. Let’s fill out our diagram!

21. Warm Up 10/24 What is a solution? What are two types? Describe each.

22. ACTIVE TRANSPORTACTIVE TRANSPORT * The movement of materials through a cell membrane using energy. This occurs when a cell needs to take in a substance that is higher concentration inside the cell instead of outside the cell. The cell needs to move materials in the opposite direction as diffusion. Cells can do this but they have to use energy.

23. Active transportation Endocytosis –Proteins in the cell membrane function to Cell pick up molecules that are needed inside using energy

24. TRANSPORT PROTEINS Proteins that are located in the cell membrane that “pick up” molecules outside of the cell and bring them in. Process requires the cell to use energy.

25. Active transport Engulfing or phagocytosis Cell membrane surrounds or engulf a particle to bring it in to the cell using energy Once is engulf the cell membrane connects and form a vesicle or vacuole

26. Phagocytosis Paramecium eating yeastParamecium eating yeast Contractile vacuole Amoebas eating parameciumAmoebas eating paramecium More amoebas

27. Active transport Exocytosis the process by which a cell packages materials in membrane secretory vesicles inside the cell and directs them to fuse with the cell membrane releasing the packaged materials to the exterior space.

28. Active TransportActive Transport BP

29. Question: How is active transport different than diffusion?  Diffusion: high concentration ► low concentration  Active Transport: low concentration ► high concentration

30. Why are cells so small? As cells grow, the amount of surface area becomes too large to allow food and wastes to enter & leave the cell quickly enough If it grows too large it cannot function well enough to survive When a cell reaches a certain size it divides into two new cells.

31. interactive video for active and pasive transportinteractive video for active and pasive transport

32. interactive

33. http://leavingbio.net/OSMOSIS%20AND% 20DIFFUSION.htmhttp://leavingbio.net/OSMOSIS%20AND% 20DIFFUSION.htm http://www.wisc- online.com/Objects/ViewObject.aspx?ID= AP1903http://www.wisc- online.com/Objects/ViewObject.aspx?ID= AP1903 http://www.wisc- online.com/Objects/ViewObject.aspx?ID= AP11403http://www.wisc- online.com/Objects/ViewObject.aspx?ID= AP11403 http://www.wisc- online.com/Objects/ViewObject.aspx?ID= AP1101http://www.wisc- online.com/Objects/ViewObject.aspx?ID= AP1101

34. http://www.udel.edu/biology/ketcham/micr oscope/testFLV8.htmlhttp://www.udel.edu/biology/ketcham/micr oscope/testFLV8.html