Several classes of biological reactions that are mediated by an enzyme and a co-factor can occur, to a slower extent, not only without the enzyme but even without the co-factor, under catalysis by metal ions. This observation has led to the proposal that metabolic pathways progressively evolved from using inorganic catalysts to using organocatalysts of increasing complexity. However, there is...
It is plausible that the Hadean Earth had less sub-aerial land, yet it still had an enormous number of shallow water lakes, often in closed basins, and often in association with hydrothermal fields. The N2-CO2-H2O atmosphere was likely neutral or weakly reduced (with minor CO and H2), except for short periods after major impacts capable to briefly reduce the atmosphere. Episodic drying of the...
