No soup for starters? Autotrophy and the origins of metabolism.

In recent years, several alternatives to the classical prebiotic-soup model for the origin of life have been proposed. Among these, the theory of Wächtershäuser proposes that an archaic version of the autotrophic reductive citric acid cycle, driven by pyrite formation and contained on the resulting pyrite surface, was the earliest metabolic cycle, from which the central biosynthetic pathways arose, initially without enzymes or nucleic acids.