Final answer:
The [K+] gradient is stronger than the [Na+] gradient to help maintain the cell's electrochemical gradient and membrane potential, critical for the transmission of nerve impulses and muscle contractions.
Step-by-step explanation:
The purpose of having the [K+] gradient be 2.5 times as strong as the [Na+] gradient is intrinsic to the functioning of cells, especially nerve cells. This differential in gradients is established by the action of the sodium-potassium pump (Na+/K+ ATPase), which expels three Na+ ions for every two K+ ions it imports. This activity creates an electrochemical gradient, powering processes such as nerve impulse transmission and muscle contraction. The gradient also influences the resting membrane potential, vital for cellular homeostasis.
The electrochemical gradient of K+, which is part of this dynamic, results from both the concentration gradient (potassium being higher inside than outside of the cell) and the electrical gradient (the inside of the cell being negatively charged). These combined effects contribute to the directional movement of K+ ions, generally out of the cell, countering the inward movement of Na+ ions.