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Ions - Sodium and Potassium quiz #2

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  • What is the most abundant intracellular cation?
    The most abundant intracellular cation is potassium.
  • What ions rush into a neuron during depolarization?
    Sodium ions rush into a neuron during depolarization.
  • Which of these receptor molecules would allow Na+ to flow into the cell? A) Voltage-gated sodium channels B) Sodium-potassium pump C) Potassium leak channels D) Calcium channels
    A) Voltage-gated sodium channels
  • Why is the sodium-potassium pump important?
    The sodium-potassium pump is important for maintaining the resting membrane potential, regulating cell volume, and ensuring proper nerve and muscle function.
  • What substance blocks voltage-gated sodium channels?
    A) Tetrodotoxin
  • How do the concentration and electrical gradients influence the movement of sodium and potassium ions across the cell membrane in a resting neuron?
    In a resting neuron, the concentration gradient drives sodium ions (Na+) into the cell (high concentration outside, low inside) and potassium ions (K+) out of the cell (high concentration inside, low outside). The electrical gradient, due to the negatively charged cytosol, attracts both positively charged sodium and potassium ions into the cell. Thus, for sodium, both gradients favor entry into the cell, while for potassium, the concentration gradient favors exit and the electrical gradient favors entry.