1. Transport through the Cell Membrane

2. Passive Transport
Movement across a cell membrane that does not require energy
2 examples:
Diffusion
Osmosis

3. Diffusion
Movement of a substance from areas of higher concentrations to areas of lower concentrations
Ex. Food coloring in water

6. Concentration Gradient
Difference in the concentration of a substance

7. Equilibrium
Concentration of a substance is equal throughout an area

8. Facilitated Diffusion
Type of passive transport that uses proteins to move substances down their concentration gradient.
Ex: There are specific proteins that help move sugars into the cell

9. Ion Channels

11. Osmosis Diffusion of water
- Osmosis in lettuce
Why should you gargle with salt water when you have a sore throat?

12. Answer Pain caused by swelling of throat tissues (these contain water)
Salt water has a lower concentration of water than the throat tissues.
When a person gargles with salt water, the water from the throat tissues moves to the salt water.
Loss of water from throat tissue results in less swelling and pain.

13. Question
Why do plants along side of the road die after a winter where roads were heavily salted? Explain in terms of osmosis.

14. Answer
The higher than normal amount of salt in the plants’ environment causes their cells to lose water through osmosis.
Their leaves begin to look they have been through a very hot, dry summer.
Eventually the plants die because they do not have enough water to live.

15. Question
Why do wooden drawers of a dresser become sticky after a rain storm or a high humidity day? Explain in terms of osmosis.

16. Answer
On very wet days, wooden drawers in dressers absorb water from the air because of osmosis. This absorption warps the wood, making the opening and closing of drawers difficult. In drier weather water is lost from the wood, and the drawers return to their normal size.

17. Movement of Water
Solute: the substance that is dissolved in a solution, the smaller amount.
Solvent: dissolves the solute in a solution, the larger amount
Ex: Make a solution of saltwater.
Solute: Salt
Solvent: Water
Water is the universal solvent.

18. Hypertonic solution: solution is more concentrated (more solute), water moves out of the cell

19. Hypotonic solution: solution has a lower concentration (less solute) water moves into the cell

20. Isotonic: concentration is equal (equal amts of solute), no water movement

21. Hypertonic, Hypotonic and Isotonic Solutions
If the fluid outside the cell has……
Then
Outside
Fluid is……
Water
diffuses……
Effect on Cell
Higher solute concentration than the inside
Hypertonic
Out of cell
Cell Shrinks
Lower concentration than the inside
Hypotonic
Into cell
Cell swells
Equal concentration to the inside
Isotonic
Equally
Cell stays the same size

23. Questions
Why are green leafy vegetables sprinkled with water at the supermarket?
Why is salt sometimes used to preserve food?
Why should you not drink sea water?

24. Answers This prevents them from wilting due to water loss
Because a salt solution is hypertonic , the microorganisms present on the foods shrink and die.
Sea water contains high concentrations of solutes. Cells in the body lose water because of osmosis, possibly causing death.

25. http://www. northland. cc. mn
animations/transport1.html

26. Active Transport
Chapter 4.2

27. Active Transport
Transport of substances against their concentration gradient, uses energy
Energy is in the form of ATP
Adenosine Triphosphate
Carrier proteins help move substances

29. Sodium-Potassium Pump
Transports sodium and potassium Ions against their concentration gradient

31. Sodium-potassium pump
Chapter 4
Cells and Their Environment
Sodium-potassium pump
pumps three
pumps two
sodium ions
potassium ions
out of the cell
into the cell

32. Sodium Potassium Pump
hill.com/olcweb/cgi/pluginpop.cgi?it=swf::535::535::/s ites/dl/free/ /120068/bio03.swf::Sodium- Potassium%20Exchange%20Pump

33. Movement in Vesicles
Many substances, such as proteins and polysaccharides, are too large to be transported by carrier proteins.
These substances are moved across the cell membrane by vesicles.

34. Movement in Vesicles
Endocytosis: movement of a substance into the cell.
Cell membrane forms a pouch and pinches off
Exocytosis: movement of a substance out of the cell
Vesicles fuse with the cell membrane and empty their contents outside the cell.

35. Endocytosis

36. Exocytosis

37. Review of Cell Processes
hill.com/olc/dl/120068/bio02.swf Exo and Endo animation
ter_group.htm?cin=2&rg=animated_biology&at=anim ated_biology&var=animated_biology
animations/transport1.html