1. 7-3 Cell boundaries

2. Cell membrane
Define: The cell membrane regulates what enters and leaves the cell and also provides protection and support.
Composition: Made up of a double-layered sheet called a lipid bilayer
The lipid bilayer gives the cell membrane a flexible structure that forms a strong barrier between the cell and its surroundings.
The lipid bilayer also includes proteins used to channel molecules across and carbohydrates for communication.

4. Cell Wall
The main function of the cell wall is to provide support and protection for the cell
Plant cell walls are made up of cellulose

5. Quick Review Solution – A mixture of two or more substance
Solvent – The liquid in which a solute is dissolved to form a solution
Solute – The substance dissolved in the solution
Concentration – The mass of a solute found in a volume of solution. Mass / Volume (g/L)

6. Transport Active Passive
Transport across a membrane that requires the cell to use energy
Transport across a membrane that requires the cell to use NO energy

7. Diffusion
Diffusion is the process of particles moving from an area of high concentration to an area with low concentration
When the concentration of the solute is the same throughout a system, the system has reached equilibrium
Because diffusion depends upon random particle movement, substances diffuse across membranes without requiring the cell to use energy

8. Diffusion does not require energy!

9. FAcilitated diffusion
Few molecules are too big to get through the membrane by themselves.
Facilitated: Make an action or process easier.
Facilitated diffusion: Molecules that cannot normally pass through the cell membrane get help using their own personnel protein channel.
NO ENERGY REQUIRED!!!

10. Active Transport Uses energy
Generally carried out by transport proteins or “pumps”
“Pumps” work pumping concentration from low to high. (Backwards from normal)

11. Osmosis
Most biological membranes are selectively permeable. Only allowing some substances through and denying others.
Osmosis is the diffusion of water across a selectively permeable membrane.

12. How osmosis works
Movement of WATER from an area of high concentration to an area with low concentration.
Water will continue to move across a membrane until equilibrium is complete.
Isotonic – Same strength of solute
Hypertonic – Above strength of solute
Hypotonic – Below Strength of solute

13. Osmotic Pressure
For cells to survive, they must find a way to balance the intake and outtake of water.
If balance is not met, a force called osmotic pressure occurs. Creating a situation where cells will struggle to survive.

15. Endocytosis
Process of taking material into the cell by means of infolding or pockets.
Pocket breaks loose and forms a vacuole.
Two main types of endocytosis
Phagocytosis
Pinocytosis

16. Phagocytosis
“Cell Eating”
Cell slowly surrounds and engulfs the food.

17. Pinocytosis “Cell Drinking”
Cells form tiny pockets around the cell wall and fill them with liquid and pinch off

18. Exocytosis Removal from the cell
Vacuole fuses with the cell membrane, forcing the contents out of the cell
Contractile vacuole in some fresh water protists.