Here's how it works:

1. ATP Binding: The pump binds to ATP.

2. Phosphorylation: ATP is hydrolyzed, releasing energy and transferring a phosphate group to the pump protein. This phosphorylation changes the pump's shape.

3. Sodium Export: The shape change causes the pump to open towards the outside of the cell, releasing sodium ions (Na+) into the extracellular fluid.

4. Potassium Import: The pump then binds to potassium ions (K+) from the extracellular fluid.

5. Dephosphorylation: The phosphate group detaches from the pump, causing it to revert to its original shape. This opens the pump towards the inside of the cell.

6. Potassium Release: The pump releases potassium ions into the intracellular fluid.

The cycle then repeats, continuously moving sodium out of the cell and potassium into the cell against their concentration gradients.

Key Points:

* ATP is the primary energy source for most cellular processes, including active transport.

* The sodium-potassium pump is a crucial example of active transport, moving ions against their concentration gradients.

* This pump is essential for maintaining the membrane potential of cells, which is crucial for nerve impulse transmission, muscle contraction, and many other cellular functions.