In a clever experiment performed in 1962, a cysteine already attached to its tRNA was chemically converted to an alanine. These “hybrid” tRNA molecules were then added to a cellfree translation system from which the normal cysteine-tRNAs had been removed. When the resulting protein was analyzed, it was found that alanine had been inserted at every point in the polypeptide chain where cysteine was supposed to be. Discuss what this experiment tells you about the role of amino acylt RNA synthetases and ribosomes during the normal translation of the genetic code.