The picture painted by Russell and Martin is striking indeed. The last common ancestor of all life was not a free-living cell at all, but a porous rock riddled with bubbly iron-sulphur membranes that catalysed primordial biochemical reactions. Powered by hydrogen and proton gradients, this natural flow reactor filled up with organic chemicals, giving rise to proto-life that eventually broke out as the first living cells - not once but twice, giving rise to the bacteria and the archaea.-- from Was our oldest ancestor a proton-powered rock? by Nick Lane
Many details have yet to be filled in, and it may never be possible to prove beyond any doubt that life evolved by this mechanism. The evidence, however, is growing. This scenario matches the known properties of all life on Earth, is energetically plausible - and returns [Peter] Mitchell's great theory to its rightful place at the very centre of biology.