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ACTIVE TRANSPORT. 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 )
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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
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
Sodium Potassium Pumps (Active Transport using proteins) 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 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
1 ROUGH ER Glycolipid 2 Vesicle 3 4 Secreted protein Membrane glycolipid ER 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”
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
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