Post on 17-Jan-2018
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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?
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ACTIVE TRANSPORT
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Remember….• Passive Transport does NOT require energy• Types of passive transport:
• Diffusion• Facilitated Diffusion• Osmosis
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
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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
Passive vs. Active Transport
Figure 7.17
1. PROTEIN PUMPS•Protein Pumps -transport proteins that require energy to do work•Examples: • Na+/K+ Pumps are
important in nerve responses
• H+ (proton) pump
Sodium Potassium Pumps (Active Transport using
proteins)
Protein changes conformational shape to move molecules: this
requires energy!
2. Bulk transport across the plasma membrane
• Occurs by exocytosis and endocytosis• BOTH MOVE “BIG” AMOUNTS
OF STUFF in OR out OF THE CELL
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
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Exocytosis
ER
ROUGH ER
Glycolipid
Vesicle
Membrane glycolipid
Secretedprotein
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GOLGI APPARATUS
Endocytosis• USES Energy! • Brings “BIG” materials INTO the cell
• Cell takes in macromolecules by forming new vesicles from the plasma membrane– “endo-” means “enter”
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Endocytosis
2 types of Endocytosis1. Phagocytosis
“cell eating” Cell engulfs SOLIDS into
vesicle & “digests” it2. Pinocytosis (think
“pineapple juice) “cell drinking” Cell engulfs LIQUIDS into
vesicle & “digests” it
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Additional Notes T- CHART
Passive Transport
1. NO ENERGY NEEDED
2. THREE SUB UNITS- Osmosis- Diffusion- Facilitated Diffusion3. HIGH to LOW4. SMALL MOLECULES
Active Transport
1. YES! ENERGY NEEDED2. TWO SUB UNITS- Exocytosis- Endocytosis3. LOW to HIGH4. BIG MOLECULES
DON’T FORGET