Question

Problem 10 (3 points): Assume that you are using qPCR to determine the amount of DNA in a given sample. Your calibration sample, which contained an amount of 10^-15 mol, required 12 PCR cycles to reach a specific level of PCR product. Your cell sample with an unknown DNA amount required only 9 PCR cycles to reach the same level. How many moles of DNA did the cell sample contain? Describe how you arrived at that conclusion.

Answer 1

Since the given amount is 10-15 moles so we take its aaverag i.e 12.5 moles

As we know that in each cycle of qPCR the initial amount doubles itself,so after 12 PCR cycle this 12.5 mole becomes 51200 moles by using formula 2n

To calculate for 9 cycles, suppose there was X moles,

After 9 cycles of PCR X moles will become X×2n

As both PCR becomes of same lecel,So

X×2n=212×12.5

By calculating the above equation we find X=100

So the given sample contain 100 moles of DNA.