Question

When a neuron is at "rest", there are more _____ ions on the inside of the neuron than on the outside. This helps create the difference in charge across the neuron membrane.

Answer 1

At rest, a neuron has a higher concentration of potassium ions (K+) inside than outside, contributing to a negative resting membrane potential. The sodium-potassium pump and selective ion permeability are critical for sustaining this ionic gradient.

Step-by-step explanation:

Resting Membrane Potential and Ion Distribution

When a neuron is at rest, there are more potassium ions (K+) on the inside of the neuron than on the outside. This polarized state helps to establish the resting membrane potential, typically measured as approximately -70 millivolts. The sodium-potassium pump uses ATP to maintain this ionic balance by pumping two K+ ions into the neuron and expelling three Na+ ions out. Potassium ions tend to leave the neuron through leakage channels, contributing to the net negative charge inside the neuron, while sodium ions are found at higher concentrations outside the neuron. The higher permeability for potassium movement compared to sodium movement is essential for maintaining the negative charge inside the cell, which is crucial for the function and signaling of neurons.