1. Osmosis vs. Diffusion Diffusion:
The movement of molecules from high to low concentration
Osmosis:
The movement of water through a selectively permeable membrane from high water concentration to low water concentration

2. Red Blood Cells
Homeostasis- a cell’s ability to maintain equilibrium (balance) or stability
If water continues to move in, CYTOLYSIS will result (cell bursts)
If water continues to move out of the cell Plasmolysis results (cell shrivels)

3. Passive Transport NO energy needed ALWAYS - high to low concentration
Example: Oxygen moving from lungs into a red blood cell.

4. ACTIVE TRANSPORT REQUIRES ENERGY!
Movement from Low Concentration to High Concentration. (an uphill battle!)

5. Endocytosis Exocytosis Movement in Vesicles 2 Types:
For macromolecules (large molecules) and nutrients which are too big for the other methods
2 Types:
Endocytosis
endo – within- enter
Cyto- cell
Exocytosis
exo – without-exit
Cyto-cell

6. Endocytosis Exocytosis Used to engulf large particles
Called “cell eating”
Moving large molecules OUT of the cell (EXIT)
Reverse of endocytosis
Removes waste from cell
Exocytosis

7. Endocytosis
Outside the cell
cytoplasm
Used to engulf large particles such as food, bacteria, etc. into vesicles
Called “Cell Eating”

8. Moving the “Big Stuff” Exocytosis- moving things out.
Molecules are moved out of the cell by vesicles that fuse with the plasma membrane.
This is how many products and waste are secreted

9. Exocytosis The opposite of endocytosis is exocytosis
Exocytosis The opposite of endocytosis is exocytosis. Large molecules that are manufactured in the cell are released through the cell membrane.
Inside Cell
Cell environment

10. Endocytosis and Exocytosis in Action
agocitosis.swf