1. The cell membrane

2. Characteristics Regulates what enters & leaves the cell
Protection & support
Lipid bilayer – tough & flexible
semipermeable

5. Proteins - form channels & pumps that help move material across the cell membrane
Carbohydrate – i.d. cards; allow cells to identify one another

8. Diffusion -02, CO2
Molecule movement – from an area of higher concentration to an area of lower concentration
Goal: Equilibrium – when the solute is the same inside & outside the cell
Does NOT require energy!

9. Concentration gradient
When particles are uneven in concentration in one area, they move with the concentration gradient until equilibrium is reached.

13. Osmosis Diffusion of water molecules Moves from high to low
Osmotic pressure effects can be bad 
Let’s see:

16. Solutions
Hypotonic – more water on the outside – cell fills up & explodes
The solution is below strength in solute
Animal cells- swelling and bursting= cytolysis

17. Hypertonic – more solute (salt) on the outside –cell loses water – cell shrinks
The solution is above strength in solute
Plant cells shrinking=plasmolysis
Animal cells = crenation

18. Remember: SALT SUCKS!!!
Isotonic - solutions are the same strength; no change

21. Facilitated Diffusion
another type of passive transport
Molecules go through protein channels
Molecules that cannot move through the lipid bilayer

22. Ex. Sugar & salts-(Glucose)
Molecules move from higher concentration to lower concentration
No energy needed

24. Active Transport
Movement of molecules from lower concentration to higher concentration
Example: Sodium (Na+) low on the inside, Potassium (K+) is high – keep it that way!
Requires energy

25. Requires use of “protein pumps”
2 types:

26. Endocytosis
Taking material into the cell by an infolded pocket of the cell membrane itself
Pocket breaks loose & forms a vacuole

28. Ex. white blood cells attacking bacteria

29. Exocytosis Moving stuff OUT of the cell Vacuole surrounds material
Vacuole fuses with cell membrane
Material is forced out