ACTIVE TRANSPORT
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Transcript of ACTIVE TRANSPORT
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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 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
• Antiports and Symports (Cotransport)
• 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