1. The Cell Membrane

4. What is a membrane?
A membrane is a device that selectively permits the separation of one or more materials from a liquid or gas.
                          ?

5. Passive Transport
The transport of substances through the cell membrane without using energy.

6. Now there are two different ways to transport material through the cell membrane WITHOUT using energy:
Diffusion and Osmosis

7. Diffusion
The process of moving from areas of high concentration to areas of low concentration

9. Diffusion Demonstration Model
Molecules are always in motion
In a closed system the molecules evenly try to distribute
Which results in a the initial movement of molecules from high to low concentrations
Once an equilibrium is reached there is no net movement of molecule.

10. What is separating the two different types of beads?
How do the two volumes compare in this model?
Which side of the model has a higher concentration of beads?
How is diffusion going to take place?
What happens with continued shaking?
Is equilibrium reached? (Has homeostasis been reached?)

11. is the maintenance of a stable internal environment.
Add: Homeostasis
is the maintenance of a stable internal environment.

12. Dialysis
It’s a process that separates solvents from blood. Such as removing glucose or fats with out removing the important molecules that our blood needs.
The tubing used in semi-permeable. Meaning some material can pass through and other cannot.

14. Osmosis

15. Osmosis
The diffusion of water from areas of high concentration to areas of low concentration through a semi-permeable membrane.

16. Water moves from a high concentration of water (less salt or sugar dissolved in it) to a low concentration of water (more salt or sugar dissolved in it).  This means that water would cross a selectively permeable membrane from a dilute solution (less dissolved in it) to a concentrated solution (more dissolved in it).

17. Water can cross the cell membrane through the lipid bi-layer and with special proteins. If enough water enters the cell by osmosis, the cell can swell enough to burst open and die.  This is demonstrated in the picture.

18. In this picture a red blood cell is put in a glass of distilled water (all water with no salt or sugar in it).  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. 

19. Osmosis Cont.
The concentration (amount) of all substances affects the movement of materials in and out of the cell.

20. Hypotonic Solute concentration: contains a low concentration of solute
Water concentration: contains a high concentration of water
Water movement: water diffuses into the cell
Effect on the cell: causing the cell to swell and possible explode

22. Cells in hypotonic solution

23. Draw a picture

24. Isotonic Solute concentration: is equal to the water concentration
Water concentration: is equal to the solute concentration
Water movement: equal diffusion (water diffuses into and out of the cell at equal rate)
Effect on cell: none

25. Normal cells in isotonic solution

26. Draw a picture of an isotonic solution next to the definition

27. Hypertonic
Solute concentration: contains a high concentration of solute
Water concentration: contains a low concentration of water
Water movement: water diffuses out of the cell
Effect on the cell: causing the cell to shrivel

28. Cells in hypertonic solution

29. Draw a picture next to the definition

31. Quiz yourself

34. Active transport

35. Active transport
The transport of molecules from areas of high to low concentration with the use of energy.
The cell energy is the ATP made in the mitochondria.

36. Bulk movement of substances across the membrane
Endocytosis:
Phagocytosis
Pinocytosis
Exocytosis

37. Endocytosis
A process by which a cell surrounds and takes in materials from its environment by engulfing them.

38. Phagocytosis
Process in which phagocytes engulf and digest microorganisms and cellular debris
"phagocyte" or eating cell
(phago = "eating", cyte = "cell").
An important defense against infection

40. Pinocytosis
process by which certain cells can engulf and incorporate droplets of fluid

42. Exocytosis
when transport
is out of the cell.