On the Origin of Life: From networks of prebiotic reactions to the DNA-protein world

Life is thought to have started around 3.8 to 4 billion years ago and have split into Bacteria and Archaea some 3.5 billion years ago, at which time we already had biochemically modern cells with a plasma membrane, a universal genetic code, a comprehensive core metabolism, and prototypes for all the main families of folded proteins. Here we will review the obstacles that Life most likely encountered in its progress over the first half billion years, focusing particularly on the last hurdle, the protein folding problem.