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Question: Answered & Verified by Expert
A virus with ssDNA is discovered. Its DNA is amplified by running 10 cycles of PCR. How many dsDNA strands will be formed at the end?
BiologyBiotechnology - Principles and ProcessesNEET
Options:
  • A 10
  • B 512
  • C 1024
  • D 102
Solution:
1404 Upvotes Verified Answer
The correct answer is: 512
Polymerase chain reaction (PCR) is a process to amplify nucleic acid sequences. In this process, the DNA is replicated multiples times by adding synthesized primer which attach to the denatured DNA strand and are extended using a thermostable polymerase enzyme -Taq polymerase obtained from a thermophilic bacterium, Thermus aquaticus. DNA is denatured by heating and breaking the H-bonds.

In each cycle of PCR the dsDNA is doubled, so after n cycles the copies of DNA will be 2n .

Now the given sample of viral DNA is single stranded, therefore, in the first cycle it will form a dsDNA. And in the consecutive cycles the dsDNA will double in copies. Therefore, after 10 cycles the number of copies will be 29=512 .

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