Life's energy currency, the proton gradient, is older than life itself

Lane argues that the mechanism nearly all life uses to generate energy, pumping protons across a membrane and letting them flow back through a molecular turbine to make ATP, did not need to be invented by early cells because it already existed naturally at alkaline hydrothermal vents. These vents produce a natural pH gradient between alkaline vent fluid and more acidic ocean water, mirroring the gradient cells now generate biologically.

He contends that early proto-cells, trapped in the vents' microscopic mineral pores, simply harnessed this pre-existing geochemical gradient rather than evolving proton pumping from scratch, an enormous evolutionary leap. This explains why the mechanism is universal across all known life, from bacteria to humans, inherited from a shared ancestor adapted to an environment where the gradient was simply given for free.

Lane treats this as the deepest possible explanation for a biochemical universal, tracing a modern cellular mechanism back to specific ancient geology rather than an arbitrary evolutionary accident.

Takeaway: the way your cells make energy right now traces back to free energy gradients at ancient seafloor vents.