Evolution of the Genetic Code

The genetic code is the set of rules that all living cells use for the synthesis of proteins, and to this purpose they employ three different types of RNAs: the messenger-RNAs, the transfer-RNAs and the ribosomal-RNAs. The messenger-RNAs carry genetic information in the form of sequences of codons, where the codons are groups of three nucleotides. The transfer-RNAs transport amino acids to the place of protein synthesis and contain anticodons that recognize the codons of the messenger-RNAs. The ribosomal-RNAs are the molecules that actually stick amino acids together in the order provided by the messenger-RNAs.