Energy and Matter at the Origin of Life

There is a paradox at the base of life. Membrane bioenergetics - the use of ion gradients across membranes to drive carbon and energy metabolism - are universal, but membranes are not. Radical differences between bacteria and archaea in membrane chemistry and active ion pumping suggest that LUCA, the last universal common ancestor, may have used natural proton gradients in alkaline hydrothermal vents to drive growth. I will outline a possible scenario for the origin of life in this environment, and present some experimental and modelling results which suggest that proton gradients could have driven the transition from geochemistry to biochemistry, and the deep divergence of archaea and bacteria.