During protein synthesis peptide bonds are formed between the amino acids. Each codon on m-RNA consists of three nucleotides (triplet). A complementary antocidon is carried by t-RNA molecule. Such t-RNA has a specific amino acid attached to it. Codon and anticodon recognition takes place at a specific site and related amino acids are brought into definite positions. These amino acids are joined by the peptide bonds between COOH and OH groups to form a polypeptide chain.