1. All Cells: Cell Membrane Cell Wall What are the Cell Boundaries???
Some Cells, Mostly PLANT:

2. Cell Membrane aka. THE GATE KEEPER
Function: regulates what enters and leaves the cell
Function: provides protection and support
aka. THE GATE KEEPER

3. Hydrophilic To Fear Hydrophobic TO LOVE The phospholipid bilayer
Function: give membranes a flexible structure that forms a STRONG barrier between the cell and its surroundings
Hydrophilic
TO LOVE
To Fear
Hydrophobic

4. Cell Wall: found in plants, algae, and many prokaryotes
Porous: allow water, oxygen, carbon dioxide, and other substance to pass
MAIN Function: provide support and protection for the cell
Made mostly from:
carbohydrates
:the polysaccharide…Cellulose

5. Diffusion
The process in which particles move from a HIGHER concentration to a LOWER concentration of particles
NO ENERGY is required
The particles are working toward EQUILIBRIUM

6. Diffusion is ALWAYS occurring
Molecules that are dissolved in water take up space
SALT IS NOT ALLOWED TO DIFFUSE THROUGH THE MEMBRANE

7. Question #1:
If a solution is 10% salt, what percentage of the solution is water?
90%

8. This cell’s cytoplasm is 95% water.
Question #2:
This cell’s cytoplasm is 95% water.
so how much is dissolved “stuff”?
The cell is placed in a 10% salt solution.
So how much is water?
WHAT HAPPENS TO THE CELL?
10% salt
90% water
95% water
5% “stuff”

11. Diffusion Problems
Step 1: Determine the concentrations of water on both sides of the membrane
Step 2: State the direction of the diffusion that is occurring

12. when substances can pass through the membrane
What does it mean to be permeable?
What does it mean to be impermeable?
What does it mean to be selectively permeable?
when substances can pass through the membrane
when substances can't pass through the membrane
SOME substances can pass through the membrane

13. Have you ever learned by OSMOSIS?
The diffusion of WATER through a selectively permeable membrane
PROBABLY NOT!

14. Osmosis
ENERGY

16. Important Terms
Isotonic: the concentration of solutes is the same inside and outside the cell
Hypertonic: Solution has a higher solute concentration than the cell
Hypotonic: Solution has a lower solute concentration than the cell

17. Osmosis in Red Blood Cells
Normal RBC
Shrunken RBC

18. Osmotic Pressure is building!!!

19. Facilitated Diffusion
High Concentration to Low concentration
NO ENERGY required
The cell membrane protein facilitates movement
In your body: Red blood cells (RBC’s) have a cell membrane protein with an internal channel that only allows glucose to pass through

20. Active Transport ENERGY LOW concentrations HIGH concentrations
Animations
Requires
Movement of molecules from areas of
to areas of
ENERGY
LOW concentrations
HIGH concentrations

21. A few examples of Active Transport
Endocytosis: Taking materials IN
Examples of endocytosis
Phagocytosis: cell eating
Endocytosis - Animation of Phagocytosis
Pinocytosis: WATER
Endocytosis - Animation of Pinocytosis
Exocytosis: Letting Materials OUT

25. Comparing Passive and Active Transport