Na K exchange pump Very important to cell Example of ion exchange pump

Na k exchange pump very important to cell example of

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Na + /K + exchange pump : Very important to cell! Example of ion exchange pump: transports > 1 ion in opposite directions Moves ions against concentration gradient 3 Na + out for 2 K + in Requires ATP hydrolysis (energy source) Maintains HIGH extracellular Na + and HIGH intracellular K + CRITICAL for homeostasis animation
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Secondary active transport “Coupled transport”, ATP used indirectly Movement of first substance down its conc. gradient powers movement of a second different substance up its concentration gradient Energy source: ionic gradient of first substance created by primary active transport earlier (ie. Na + /K + ATPase pump) Symporters vs. antiporters animation
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Secondary active transport Symporters vs. antiporters animation
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Electrochemical gradient : electrical & chemical difference across the membrane Result of membrane selective permeability, passive and active transport Represents potential energy: affects ion movement Components: Gradients across the membrane Electr ical gradient: Transmembrane potential Resting membrane potential of cells: negative inside Due to more – charged proteins inside and fewer + charged ions. Concentration ( chemical) gradient: ie. more Na + outside and more K + inside
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Vesicular transport (bulk transport) Materials move into or out of cell in sacs that bud off membranes (vesicles) Requires ATP Types: Endocytosis: substance brought from outside to inside cell Phagocytosis Pinocytosis Receptor-mediated Exocytosis: substance released from inside to outside cell
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Endocytosis Vesicle formation requires energy Phagocytosis: “cell eating”: large particles Select cells: phagocytes Surrounds with pseudopods Forms vesicle: phagosome Digests when fuses with lysosome Pinocytosis: “cell drinking”: small vesicles Bring in interstitial fluid with dissolved molecules Most cells capable phagocytosis
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Endocytosis Receptor-mediated endocytosis Very selective! Binds specific receptor Increases uptake even if limited amount in ECF Cholesterol uptake from blood into cell
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Exocytosis Vesicle fuses with plasma membrane – requires energy Contents released ( secreted) Secretion of hormones, digestive enzymes, neurotransmitters Recycling and replacement of membrane Review of endocytosis and exocytosis
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