The PCR technique doubles the amount of DNA in a sample in each cycle. If you started the PCR technique with two fragments of double-stranded DNA, calculate how many double-stranded DNA fragments you would you have after four cycles.

32

Explanation:

When we start with one fragment of DNA, 2ⁿ is the formula used to calculate the copies of the DNA after the specific number of cycle. The number of cycles is represented by n in the formula. But as in the question there are two fragments so one copy of DNA have already been completed. That why if we want to calculate the number of DNA copies produced after four cycles of PCR we have to put 2⁵ instead of 2⁴ to get the right number and that would be 32.

Pcr cycles comprises of denaturation, annealing and extension and number of PCR cycles depends on number of copies you needed. The PCR cycles will continue until it is deficient by rate on of the limiting factors such nucleotide bases.

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