Question

When the polymerase chain reaction (PCR) is used to amplify segments of DNA, the sample is first heated, and then cooled, in cycles. How many cycles of heating and cooling would be necessary to produce 16 times the original quantity of DNA?

a. 16
b. 2
c. 4
d. 6
e. 8

Answer 1

To produce 16 times the original quantity of DNA using PCR, 2⁴ = 16 indicates that four cycles of heating and cooling are required.

Step-by-step explanation:

When the Polymerase Chain Reaction (PCR) is used to amplify segments of DNA, the number of DNA molecules doubles with each cycle. To produce 16 times the original quantity of DNA, PCR would undergo a series of heating and cooling cycles, each consisting of denaturation, annealing, and extension. Since the amount of DNA doubles with each cycle, to calculate the number of cycles needed to reach 16 times the original amount, we can use the formula 2n = amount, where n is the number of cycles.

In this case, 2n = 16, so n must be 4 because 24 = 16. Therefore, four cycles would be necessary to produce 16 times the original quantity of DNA. The correct answer is c. 4.