The molecules that translate the codons into the amino acid sequence of a protein are the transfer RNA (tRNA) molecules. They function as intermediates that deliver amino acids to the mRNA.

20 distinct tRNA transfer each amino acid to the site of protein synthesis. All tRNA molecules have the same general shape, a “cloverleaf” and this shape is crucial to how they function.

The 3’ end of the open part of the cloverleaf structure is where an amino acid becomes covalently bonded to the tRNA molecule. The carboxyl groups of amino acids are attached to the 3-hydroxyl group of the adenosyl moiety through an ester bond.

The anticodon loop at the end of a base paired stem recognizes the triplet nucleotide or codon of the template mRNA. The interaction of the codon on the mRNA and the anticodon on the tRNA leads to the proper placement of an amino acid on the growing peptide chain during protein synthesis.

In all tRNA molecule, there is a loop containing the nucleotides of ribothymine and pseudouridine for binding amino acyl tRNA by ribosome and another loop containing the minor base dihydrouracil for recognition of tRNA.

Each of the different tRNA molecules is specifically recognized by an aminoacyl tRNA synthetase enzyme. These enzymes recognize the kind of amino acid that belongs to the particular tRNA and facilitates its bonding to the tRNA.