New Scientist writes on the possible origin of life on Earth:
The most counter-intuitive trait of life could be one of the best clues to its origin. At one time everyone assumed that cells got their energy using straightforward chemical reactions. However, Nobel Prize-winning biologist Peter Mitchell argued, correctly, that life is powered not by the kind of chemistry that goes on in a test tube but by a kind of electricity; the energy from food is used to pump positively charged hydrogen ions, or protons, creating an electrochemical gradient.
Proton power drives not only cell respiration, but photosynthesis too: energy from the sun is converted into a proton gradient in essentially the same way as the energy of food. This suggests that proton power is no late innovation but evolved early in the history of life, an idea supported by the tree of life. The obvious explanation is that both inherited this machinery from a common ancestor – the progenitor of all life on Earth…
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