Which cellular structure maintains the neuron's resting membrane potential by active ion transport?

Which cellular structure maintains the neuron's resting membrane potential by active ion transport?

• A. Golgi apparatus
• B. Sodium-potassium pump
• C. Ribosomes
• D. Mitochondria

Answer: (B)

Active ion transport establishes and preserves the ion gradients that underlie the neuron's resting membrane potential. The sodium-potassium pump uses energy from ATP to move three Na+ ions out of the cell and two K+ ions in, creating and maintaining the concentration gradients across the membrane. These gradients keep the inside of the neuron relatively negative and counteract the natural leakage of ions through channels, so the resting potential remains stable over time. Mitochondria supply the ATP that powers this pump, but the structure directly responsible for maintaining the resting potential through active transport is the sodium-potassium pump. Golgi apparatus and ribosomes handle protein processing and synthesis, not ion transport.

Active ion transport establishes and preserves the ion gradients that underlie the neuron's resting membrane potential. The sodium-potassium pump uses energy from ATP to move three Na+ ions out of the cell and two K+ ions in, creating and maintaining the concentration gradients across the membrane. These gradients keep the inside of the neuron relatively negative and counteract the natural leakage of ions through channels, so the resting potential remains stable over time.

Mitochondria supply the ATP that powers this pump, but the structure directly responsible for maintaining the resting potential through active transport is the sodium-potassium pump. Golgi apparatus and ribosomes handle protein processing and synthesis, not ion transport.