The production of peptides or proteins by the constituents of a living organism. The biosynthesis of proteins on ribosomes following an rna template is termed translation (TRANSLATION, GENETIC). There are other, non-ribosomal peptide biosynthesis (peptide biosynthesis, nucleic acid-independent) mechanisms carried out by peptide synthases and PEPTIDYLTRANSFERASES. Further modifications of peptide chains yield functional peptide and protein molecules.