How might you explain the discrepancy between the normal length of prolactin (199 amino acids) and the length of the polypeptide synthesized in your experiment (227 amino acids)? how might you explain the discrepancy between the normal length of prolactin (199 amino acids) and the length of the polypeptide synthesized in your experiment (227 amino acids)? in the absence of srp and er membranes, a prolactin precursor molecule is synthesized. in the absence of srp and er membranes, synthesis proceeds in the wrong direction. in the absence of srp and er membranes, introns aren't spliced from the mrna. in the absence of srp and er membranes, stop codons aren't recognized.