Question

How many copies of DNA sample are produced in PCR technique after 6-cycles?

• A. 4
• B. 32
• C. 64
• D. 16

Answer 1

The correct option is C 64

• PCR technique amplify the gene of interest in three steps namely denaturation of target DNA (thermal cycle to separate the DNA strands), annealing of primers to the ssDNA, and polymerization (extension of primer into complete DNA strand complementary to the template strand).
• After completion of one cycle of PCR, two copies of the target DNA are produced both of which serve as a template for the next PCR cycle and produce 4 copies.
• Hence, there is an exponential amplification of DNA copies.
• The total number of DNA molecules, produced after "n" PCR cycle = $2^n$. Thus, the total number of DNA molecules, produced after "6" PCR cycles = $2^6$ = 64.

Thus, the correct answer is option C.