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Resting potential and action potentials

Biology • Nervous System & Senses • Knowledge-Based • 5 questions

Resting potential and action potentials Knowledge-Based Download PDF

Biology · Human Body & Physiology · Biology · Nervous System & Senses

5 Biology practice questions on Resting potential and action potentials. Questions that assess core concepts and understanding.

Questions

  1. 1.

    During a neuronal action potential, which event directly accounts for the afterhyperpolarization (undershoot) phase where the membrane potential temporarily becomes more negative than the resting potential?

    • A) Influx of extracellular chloride ions through ligand-gated ion channels
    • B) Delayed closure of voltage-gated potassium channels resulting in sustained potassium efflux
    • C) Temporary reversal of the sodium-potassium ATPase pumping direction
    • D) Rapid reopening of voltage-gated sodium channel activation gates
  2. 2.

    When a neuronal axon reaches its threshold potential, what immediate event is directly responsible for the rapid depolarization phase of the action potential?

    • A) Rapid efflux of potassium ions through open voltage-gated potassium channels
    • B) Active extrusion of sodium ions against their concentration gradient by the sodium-potassium pump
    • C) Rapid influx of sodium ions through open voltage-gated sodium channels
    • D) Influx of chloride ions through resting leakage channels across the plasma membrane
  3. 3.

    During the propagation of a neuronal action potential, what molecular event is directly responsible for establishing the absolute refractory period?

    • A) Inactivation of voltage-gated sodium channels
    • B) Delayed closure of voltage-gated potassium channels
    • C) Activation of the sodium-potassium ATPase pump
    • D) Efflux of potassium ions through resting leak channels
  4. 4.

    Which mechanism is primarily responsible for maintaining the resting membrane potential of a neuron by actively transporting ions against their concentration gradients?

    • A) Passive diffusion of sodium ions into the cell through non-gated leakage channels
    • B) Active transport of sodium ions out of the cell and potassium ions into the cell by the sodium-potassium pump
    • C) Opening of voltage-gated potassium channels causing a rapid efflux of positive ions
    • D) Inward movement of large negatively charged proteins across the axonal membrane
  5. 5.

    Which of the following events is directly responsible for the repolarization phase of an action potential in a neuronal axon?

    • A) Rapid influx of sodium ions through ligand-gated sodium channels
    • B) Active transport of three potassium ions outward by the sodium-potassium pump
    • C) Inactivation of voltage-gated sodium channels and the outward flow of potassium ions through voltage-gated potassium channels
    • D) Influx of chloride ions that neutralizes positive charges inside the axon