Transfer  RNA  (tRNA)  molecules  play  an  very significant  role  in  protein  synthesis. Each tRNA becomes covalently bonded to a particular amino acid  to  create  aminoacyl- transfer RNA that  recognizes  the  corresponding  codon  in mRNA  and  make sure in which  the  correct  amino  acid  is  added  to  the  growing polypeptide  chain. The transmit RNAs are small molecules, only 74-95 nt long, that form distinctive   cloverleaf secondary structures shown in the figure by internal base pairing. The stem-loops of the cloverleaf are called as arms: