You have a small gene that you wish replicated by PCR. You add radioactively labeled nucleotides to the PCR thermocycler. After 3 replication cycles, what percentage of the DNA single- strands are radioactively labeled?

Question

Quizplus · Accepted Answer

After 3 cycles of PCR, 87.5% of the DNA strands are radioactively labeled. This is because, in each cycle, the newly synthesized strands incorporate the labeled nucleotides, doubling the amount of labeled DNA. After the first cycle, 50% is labeled (the new strands), after the second cycle, 75% (half of the original strands plus all new strands), and after the third cycle, 87.5% (half of the remaining unlabeled original strands plus all new strands).

You Have a Small Gene That You Wish Replicated by PCR