A cation that is more abundant as a solute in the cytosol of a neuron than it is in the interstitial fluid outside the neuron is
A) HCO₃⁻.
B) Cl⁻.
C) Ca⁺⁺.
D) Na⁺.
E) K⁺.

Question

Quizplus · Accepted Answer

Neurons maintain a higher concentration of K⁺ ions inside the cell compared to the interstitial fluid outside the neuron. This is due to the action of the Na⁺-K⁺ pump, which actively transports three Na⁺ ions out of the cell and two K⁺ ions into the cell for each ATP molecule hydrolyzed. Therefore, K⁺ ions are more abundant as a solute in the cytosol of a neuron than they are in the interstitial fluid outside the neuron.

A Cation That Is More Abundant as a Solute in the Cytosol