1. Bell Work
1. If a membrane allows movement of only certain materials, it is called ___.
Somewhat permeable
Selectively permeable
Somewhat impermeable

2. Notes: Cell Membrane Cell membranes are also called plasma membranes
Facts:
Selectively permeable
Allows certain materials to move in and out of the cell when needed, but keeps other material from crossing the membrane
Made of phospholipid bilayer
Water soluble phosphate head (hydrophilic)
Water insoluble fatty acid tail (hydrophobic)
Has various carbohydrates, proteins and cholesterol mixed into the bilayer

3. Question 1. Which of these is NOT a type of cellular transport?
endocytosis
exocytosis
diffusion
nucleocytosis

4. Question 2. The cell membrane is made primarily of ___. carbohydrates
Nucleic acids
proteins
phospholipids

5. Question 3. When active transport is used, the cell ______.
Does not use any of its own energy
Uses some of its own energy
Uses energy from other cells
Uses the energy stored mainly in the nucleus

6. Question During passive transport, a cell ________.
Does not use any of its own energy
Uses some of its own energy
Uses energy from other cells
Uses the energy stored mainly in the nucleus

7. Notes: Cellular Transport
Diffusion
Movement of molecules from an area of higher concentration to an area of lower concentration.
Passive Transport
It does not require energy
Oxygen and Carbon Dioxide use diffusion
Not all molecules can enter and leave by diffuison
Once equilibrium is reached they stop

8. Notes: Cellular Transport
Concentration Gradient
The name of the difference that exist when there is a difference in concentration in two areas
Equilibrium
When the concentration on both sides of the cell membrane are equal

9. Draw Concentration Gradient

10. Notes: Facilitated Diffusion
Transport Proteins
Allow some of the ions, sugars, and amino acids to pass through from an area of high concentration to an area of low concentration
Many different types
Each selective for a specific molecule
Form of PASSIVE TRANSPORT

11. Questions Why is diffusion a type of passive transport?
A. It moves materials across a cell membrane
B. It does not require any of the cell’s energy
C. It does not need activation by an enzyme
D. It continues until equilibrium is reached

12. Questions During diffusion, molecules move _____.
A. from an area of higher concentration to an area of lower concentration
B. from an area of lower concentration to an area of higher concentration
C. across a cell membrane with the use of cellular energy
D. against a concentration gradient

13. Notes: Osmosis Osmosis 2 Facts Passive transport
Moves molecules down a concentration gradient
2 Facts
Always a movement of water molecules
Moves water molecules across a selectively permeable membrane through which the solute (dissolved particles) cannot cross

14. Notes: Osmosis Osmosis
Solute particles are too large to pass through the selectively permeable membrane
Like oil and water’s inability to mix, particles that are water soluble cannot pass through the middle of the membrane
To bring about equilibrium, either facilitated diffusion or osmosis must take place

15. Notes: Isotonic Solution
The solution on the outside of the membrane has the same concentration as the solution on the inside of the membrane
No net movement of water molecules across the membrane

16. Notes: Hypertonic Solution
The solution outside the membrane contains less water and more solute than the solution inside the membrane
water rushes out of the cell
Cell shrivels up
Example: salt on a slug

17. Notes: Hypotonic Solution
Solution on the outside of the cell membrane has a greater concentration of molecules than the solution inside the cell
More water on the outside
Ex. Wilted vegetable (celery)
Water rushes in an the cells swell

18. Notes: Active Transport
Used to move molecules against a concentration gradient
Requires Energy
3 Types of Transport Proteins help move substances in and out of the cell
channel proteins
carrier proteins
gate proteins

19. Notes: Transport Proteins
Often the protein has a certain shape that allows it to stick to a molecule with a matching shape
Uses chemical energy to move against the gradient

20. Notes: Endocytosis Endocytosis
A way of allowing particles that are too big to cross the cell member to enter
Particle is enclosed with material from the cell, then pulled into the cell
In = En
Into the cell = ENDOcytosis

21. Notes: Exocytosis Exocytosis Exit the cell = EXocytosis
Used to get rid of large particles
Undigested food, waste products or hormones
Material is enclosed in a vesicle
Vesicle meets the cell membrane, breaks open, then fuses with the membrane
Particles are released to the outside of the cell
Exit the cell = EXocytosis