Question

How many DNA duplexes are obtained from one DNA duplex after 8 cycles of PCR?

• A. 8
• B. 16
• C. 128
• D. 256

Answer 1

The correct option is D 256

The number of double-stranded DNA pieces is doubled in each cycle of the PCR.
So, after n cycles of PCR, number of dsDNA obtained = $2^n$ copies of DNA.
After 8 cycles of PCR = $2^8$ copies of DNA
= 256 copies of DNA.