In translation process , proof reading of mRNA is done by :

Ans. is 'b' Amino acyl-t- RNA synthetase : Aminoacyl - tRNA synthetase :"This family of enzymes is required for attachment of amino acids to their corresponding tRNAs. Each member of this family recognized a specific amino acid and the tRNA that correspond to that amino acid. Each amino acyl - tRNA synthetase catalyzes a two-step reaction that results in the covalent attachment of an amino acid to its corresponding tRNA . The extreme specificity of the synthetase in recognising these two structures is largely responsible for the high fidelity of translation of the genetic message". - Lippincott, 2/e.