Abstract

Many solar systems in the universe may be expected to contain rocky planets that have accreted organic compounds. These compounds are likely to be universally found. In addition, the chemistry of sulfur, phosphorus, and iron is likely to dominate energy transductions and monomer activation, leading to the eventual emergence of polymers. Proteins and polynucleotides provide living matter with function, structure, and information. The conceptual puzzle regarding their emergence is discussed. The fitness of various elements to serve various roles is analyzed from the viewpoint of electron orbitals. Elements with d orbitals are of central importance.