You perform a series of experiments on the synthesis of the pituitary hormone prolactin, which is a single polypeptide chain 199 amino acids long. the mrna coding for prolactin is translated in a cell-free protein synthesizing system containing ribosomes, amino acids, trnas, aminoacyl-trna synthetases, atp, gtp, and the appropriate initiation, elongation, and termination factors. under these conditions, a polypeptide chain 227 amino acids long is produced.