Final answer:
The ATP-driven Na⁺ pump, or sodium-potassium pump, is key for cell membrane electrochemical gradients, cycling through distinct steps to transport ions using ATP energy.
Step-by-step explanation:
The ATP-driven Na⁺ pump, also known as the sodium-potassium pump or Na⁺/K⁺ ATPase, is essential for maintaining the electrochemical gradient across the cell membrane. This pump actively transports three sodium ions out of the cell and two potassium ions into the cell against their concentration gradients, using energy from the hydrolysis of ATP. The process is indeed step-dependent, consisting of multiple stages:
- Three sodium ions bind to the pump inside the cell.
- ATP is hydrolyzed, transferring a phosphate group to the pump, inducing a conformational change.
- The pump opens towards the exterior, releasing the sodium ions.
- Two potassium ions bind to the now-vacant sites on the pump.
- A subsequent conformational change happens, leading to dephosphorylation of the pump and release of the potassium ions inside the cell.
- The pump returns to its original conformation, ready to start another cycle.
This mechanism is vital for multiple cellular processes, including nerve impulse transmission and muscle contraction.