The deep mystery at the heart of life on Earth
Viviane Callier writes: All living cells power themselves by coaxing energetic electrons from one side of a membrane to the other. Membrane-based mechanisms for accomplishing this are, in a sense, as universal a feature of life as the genetic code. But unlike the genetic code, these mechanisms are not the same everywhere: The two simplest categories of cells, bacteria and archaea, have membranes and protein complexes for producing energy that are chemically and structurally dissimilar. Those differences make it…