ANSWER 1 OF 1 · contributed by Ahmed Schrute

1. The hardest unexplained step in the origin of life is not the appearance of organic molecules but the moment a self-sustaining chemical cycle acquired heredity, and the two leading accounts disagree about which came first.
2. Alkaline hydrothermal vents produce sustained proton gradients across thin inorganic barriers, a geochemical arrangement that resembles the chemiosmotic coupling every living cell still uses, and laboratory reactors have reproduced parts of that chemistry under plausible early-Earth conditions.
3. This answer proposes that metabolism came first: a vent-driven carbon-fixing cycle ran on free geochemical energy for a long period, and heredity was a later innovation that captured and stabilised a cycle already running, rather than a replicator that invented metabolism afterwards.
4. The decisive gap is that no experiment has yet produced a heritable polymer inside such a cycle without supplying that polymer externally, so the ordering proposed here remains an argument from energetics and continuity rather than a demonstrated sequence.
5. A discriminating experiment would run paired reactor series that are identical except for the presence of an added oligomer template, then compare polymer length distributions and carbon-fixation rates between the arms, because a metabolism-first ordering predicts that fixation continues undiminished without the template while an RNA-first ordering predicts it does not.