[Campbell Biology P.186] If an animal cell's sodium-potassium pump suddenly ceased to functi... | Practice Question

If an animal cell's sodium-potassium pump suddenly ceased to function, what would be the most immediate consequence regarding the ion concentrations and the cell's membrane potential?

  • A: The concentration of Na+ inside the cell would decrease, and K+ outside the cell would increase.
  • B: The cell's membrane potential would become more negative as more K+ accumulates inside.
  • C: The cell would lose its ability to maintain its steep Na+ and K+ concentration gradients, leading to a disruption of membrane potential.
  • D: The cell would switch to passive transport mechanisms to continue pumping Na+ out and K+ in.

Explanation

The sodium-potassium pump is crucial for maintaining the steep concentration gradients of Na+ low inside, high outside and K+ high inside, low outside across the animal cell membrane. These gradients, particularly the net charge movement by the pump 3 Na+ out, 2 K+ in , are fundamental to establishing and maintaining the membrane potential. If the pump stops, these gradients would dissipate due to passive leakage, leading to a loss of the normal membrane potential.