C. In another experiment, each translation reaction was carried out in the presence of microsomes, and then the microsomal membranes and bound ribosomes were separated from free ribosomes and soluble proteins by centrifugation. For each translation reaction, both the total reaction (T) and the microsomal membrane fraction (M) were resolved in adjacent gel lanes. Based on the amounts of labeled polypeptide in the membrane fractions in the autoradiogram depicted below, how long is the prolactin nascent chain when SRP binds to take the peptide to the microsomal translocon? (1 mark). Why is there no band visible in the 70M sample? (1 mark).