Final answer:
The Na+-K+ pump's crucial role is to maintain electrochemical gradients by using ATP to transport Na+ out and K+ into cells, essential for nerve impulse conduction.
Step-by-step explanation:
The most important function of the Na+-K+ pump (also known as Na+/K+ ATPase) is to maintain the electrochemical gradient across the cell membrane by actively transporting sodium ions (Na+) out of the cell and potassium ions (K+) into the cell against their concentration gradients. This process requires energy, which is obtained from the hydrolysis of adenosine triphosphate (ATP). In nerve cells, this activity is critical for maintaining the negative electrical gradient necessary for the propagation of nerve impulses, consuming the majority of the cell's ATP. For each molecule of ATP utilized, three Na+ ions are moved out of the cell, and two K+ ions are moved in, critical for cellular functions such as nerve impulse transmission and muscle contraction.