1. The Cell Membrane; Active & Passive Transport
Chapter 7.2 and 7.4
The Cell Membrane; Active & Passive Transport

2. The Cell Membrane Gatekeeper
Regulates what comes in and out of the cell
Main components: proteins and phospholipids

3. Cell Wall Found only in plant cells and bacteria cells
Main function is support

4. Solutions Mixtures of substances Ex. Salt + water; sugar + water
HINT!!!!!
Solute: The thing being dissolved
Solvent: Doing the dissolving

5. Diffusion
The movement of molecules from an area of high concentration to an area of low concentration
Diffusion occurs until equilibrium is reached

6. Diffusion Molecules tend to “spread out”
The difference between concentrations in space is the Concentration Gradient
No energy is required= passive transport

7. Equilibrium
When molecules are evenly spread throughout a space

8. Osmosis
The diffusion of water molecules across a membrane from areas of high to low concentration
This is passive transport it requires NO energy for osmosis
Water always moves with/down the concentration gradient
Watch the animation

9. Rule for Osmosis
If the area outside the cell has more salt – then water will be sucked out of the cell
Salt is a solute or solvent?

10. U - Tubes

11. Cells In Different Solutions
The concentration of salt is equal on both sides!
"ISO" means the same

12. Hypo = less Plants become stiff and rigid
Cell wall stops bursting because of turgor pressure
Hypo = less

13. Animal cells may burst, called cytolysis or organelles called “contractile vacuoles” remove excess water

14. Hyper = more Water moves out! (in that direction)
Cell will shrink or die, plants wilt and turgor pressure is lost

15. Why is it dangerous to drink sea water?
Why does pouring salt on a slug kill it?

16. Passive Transport Requires no energy Diffusion & Osmosis
Facilitated Diffusion – carrier proteins “help” molecules across the membrane

17. 1.  Why is the water moving toward the left side of the beaker? 
2.  Which side of the beaker is hypertonic?
3.  What is the solute?  

18. WORD LIST Diffusion Contractile Vacuole Osmosis Passive Transport
Selectively permeable
Equilibrium
Solution
Facilitated Diffusion
Hypertonic
Hypotonic
Isotonic
Know all of these words for the test

19. ACTIVE TRANSPORT Requires the cell to use energy
Proteins or Pumps found in the membrane move materials across

20. Endocytosis Taking “in” large molecules by the cell
Phagocytosis = “phood”, taking in food particles
Pinocytosis = liquid substances

22. EXOCYTOSIS Removing large particles (waste) from the cell
Stuff “exits” the cell

23. Add to Word List Active Transport Endocytosis Phagocytosis Pinocytosis
Exocytosis
Protein Pump