1. Bellringer-December 11, 2014
1. If a cell contains 85% water and is placed into a environment which is 50% water. Is the CELL hypotonic or hypertonic? In which direction will the water move, into the cell or out of the cell?
2. A cell contains 85% water and is placed into a solution which contains 90% water. Is the SOLUTION in the environment hypotonic or hypertonic? In which direction will the water move?
3. A cell contains 95% water, the environment outside the cell contains 45% solutes. Is the cell in a hypotonic or hypertonic environment?
4. A cell containing 25% solutes is placed into a solution which contains 35% solutes. Which direction will the water move, into the cell or out of the cell?
5. A plant cell containing 95% water is placed into a 10% salt solution. Is the salt solution hypotonic or hypertonic? Which direction will the water move?

2. ACTIVE TRANSPORT

3. Remember…. Passive Transport does NOT require energy
Types of passive transport:
Diffusion
Facilitated Diffusion
Osmosis

4. Active Transport Requires energy!
Molecules move against (up) their concentration gradients (from LOW concentration to HIGH)
Cells use energy to power this process
Two types: Endocytosis and Exocytosis

5. Active transport
Uses energy to move solutes against their [ ] gradients across the cell membrane
Energy required  usually ATP
Carrier proteins are used…NEVER channel proteins
Ex: sodium-potassium pump

6. Passive vs. Active Transport
Figure 7.17

7. Sodium Potassium Pumps (Active Transport using proteins)
1. PROTEIN PUMPS
Sodium Potassium Pumps (Active Transport using proteins)
Protein Pumps -transport proteins that require energy to do work
Examples:
Na+/K+ Pumps are important in nerve responses
H+ (proton) pump
Protein changes conformational shape to move molecules: this requires energy!

8. 2. Bulk transport across the plasma membrane
Occurs by exocytosis and endocytosis
BOTH MOVE “BIG” AMOUNTS OF STUFF in OR out OF THE CELL

9. Exocytosis USES ENERGY! Moves “BIG” materials OUT of the cell
Vesicle moves to the plasma membrane and fuses with it, contents are emptied from the cell
“exo-” means “exit”
Ex: hormone excretion; nerve cells and transmitters; removal of wastes

10. Exocytosis

12. ROUGH ER GOLGI APPARATUS Glycolipid Vesicle Secreted protein
Membrane glycolipid
Secreted
protein 4 1 2 3
GOLGI
APPARATUS

13. Endocytosis
USES Energy!
Brings “BIG” materials INTO the cell
Cell takes in macromolecules by forming new vesicles from the plasma membrane
“endo-” means “enter”

14. Endocytosis

15. 2 types of Endocytosis 1. Phagocytosis
“cell eating”
Cell engulfs SOLIDS into vesicle & “digests” it
2. Pinocytosis (think “pineapple juice)
“cell drinking”
Cell engulfs LIQUIDS into vesicle & “digests” it

17. Additional Notes T- CHART
Passive Transport
NO ENERGY NEEDED
THREE SUB UNITS
Osmosis
Diffusion
Facilitated Diffusion
3. HIGH to LOW
4. SMALL MOLECULES
Active Transport
YES! ENERGY NEEDED
TWO SUB UNITS
Exocytosis
Endocytosis
3. LOW to HIGH
4. BIG MOLECULES

18. DON’T FORGET