Role Of Active Transport [new] -

Just outside the city’s walls—the cell membrane—lay the extracellular world. K+ had heard legends about it from a grizzled old sodium ion: “Out there, kid, the concentration of us potassium folk is low. Really low. You’d be special. You’d be needed.”

K+ looked back one last time. “No,” he said. “It’s the only way to make a real difference.”

The gatekeeper opened its three inner pockets. “Then you must pay the price.”

K+ nodded.