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Published byChrystal Thompson Modified over 9 years ago
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Sodium-Potassium pumps The cell membrane as an electrical battery
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Active transport is responsible for cells containing relatively high concentrations of potassium ions but low concentrations of sodium ions. Requires E (ATP) The mechanism responsible for this is the sodium-potassium pump which moves these two ions in opposite directions across the plasma membrane.
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Concentrations of sodium and potassium ions on the two other sides of the membrane are interdependent, suggesting that the same carrier protein transports both ions. (green channel protein, red ATP-ase) The carrier is an ATP-ase and it pumps 3 sodium ions out of the cell for every 2 potassium ions pumped in.
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Function of the pump The Na+/K+-ATPase helps maintain resting potential, assists transport and regulates cellular volume. resting potential In order to maintain the cell’s resting potential, cells must keep a low concentration of ↓ sodium ions & high levels of ↑ potassium ions within the cell.sodiumpotassium
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Potential ? Means E possibility Potential: a gradient where there are different concentrations of ions on either side of a membrane just like a battery with + and – sides When the cell is at rest there is a homeostatic state called the resting potential & cell has good volume
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Cells need to bring in substances (glucose, amino acids) by facilitated transport The battery is maintained using ATP continuously to force sodium out of the cell & potassium into the cell. 3 Na+ out for every 2 K+ in
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Movement of sodium from one side of a cell membrane to the other side creates an osmotic gradient that drives the absorption of water.cell membrane Water diffuses back into the cell carrying needed substances = facilitated transport
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Concentrations of sodium and potassium ions on the two other sides of the membrane are interdependent, suggesting that the same carrier protein transports both ions. (green channel protein, red ATP-ase) The carrier is an ATP-ase and it pumps 3 sodium ions out of the cell for every 2 potassium ions pumped in.
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