1. Diffusion & Osmosis

2. Cell Theory 1. All living things are made of one or more cells.
2. Cells are the basic units of structure and function in organisms.
3. All cells arise from existing cells.

3. Eukaryote- organism whose cells have a nucleus.
Prokaryote- a single celled organism that lacks a nucleus and other internal compartments.
Eukaryote- organism whose cells have a nucleus.

4. The Plasma Membrane -
Define Diffusion
Gateway to the Cell

5. Structure of the Cell Membrane

6. Photograph of a Cell Membrane

7. Define Diffusion

8. Define Diffusion
The movement of molecules from a area in which they are highly concentrated to a area in which they are less concentrated.

9. Solute moves DOWN concentration gradient (HIGH to LOW)

10. Draw a diagram of an example of diffusion we saw in class.

11. See an animation of diffusion here:

12. Define osmosis

13. Define osmosis
Osmosis- the diffusion of water through a selectively permeable membrane.

14. In Other words…
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).

15. See an animation of osmosis here:

16. Lets look even further…
In this picture a red blood cell is put in a glass of distilled water.  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.

17. Permeable- allows most all things to pass through
Semi permeable- allows some things to pass through
Impermeable- things can not pass through

18. Why are osmosis & diffusion important?
This membrane is a complex structure that is responsible for separating the contents of the cell from its surroundings, for controlling the movement of materials into and out of the cell, and for interacting with the environment surrounding the cell.

19. Passive Transport- Movement across cell membrane that does NOT require energy from the cell
Active Transport- Movement across cell membrane that requires energy from the cell

20. Be ready to explain in your own words the definition of diffusion and osmosis.