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Ions - Sodium and Potassium quiz #3 Flashcards

Ions - Sodium and Potassium quiz #3
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  • What is the function of the sodium-potassium pump, and how does it maintain ion gradients across the cell membrane?
    The sodium-potassium pump uses ATP to actively transport three sodium ions out of the cell and two potassium ions into the cell, moving both ions against their electrochemical gradients. This maintains high sodium concentration outside and high potassium concentration inside the cell, which is essential for cell function and resting membrane potential.
  • What two gradients make up the electrochemical gradient that drives ion movement across cell membranes?
    The electrochemical gradient is made up of the electrical gradient and the concentration (chemical) gradient.
  • How does the concentration gradient influence the movement of sodium and potassium ions?
    The concentration gradient causes ions to move from areas of high concentration to areas of low concentration.
  • In a resting cell, where is the concentration of sodium ions highest?
    In a resting cell, the concentration of sodium ions is highest outside the cell.
  • In a resting cell, where is the concentration of potassium ions highest?
    In a resting cell, the concentration of potassium ions is highest inside the cell.
  • What direction does the electrical gradient move positively charged ions like sodium and potassium?
    The electrical gradient moves positively charged ions toward the negatively charged cytosol (inside the cell).
  • How do the concentration and electrical gradients affect potassium movement in a resting cell?
    The concentration gradient pushes potassium out of the cell, while the electrical gradient pulls it into the cell.
  • How do the concentration and electrical gradients affect sodium movement in a resting cell?
    Both the concentration and electrical gradients drive sodium into the cell.
  • What is the main function of the sodium-potassium pump in the cell membrane?
    The sodium-potassium pump uses ATP to move three sodium ions out of the cell and two potassium ions into the cell, maintaining their respective gradients.
  • Why is the sodium-potassium pump compared to a bouncer at a club?
    The pump is like a bouncer because it selectively allows potassium into the cell and ejects sodium, controlling which ions enter and leave.