Polymerase chain reaction (PCR) is a common laboratory technique used to make many copies of a particular region of DNA. PCR is usually used to create enough of the target DNA. DNA replication in organisms requires a DNA polymerase to create new strands of DNA from existing templates and this is needed in PCR. How does PCR separate the DNA strands to prepare for DNA replication?

A) Temperature in PCR does not influence DNA replication.

B) Low temperature is used in PCR to separate the DNA strands by breaking the hydrogen bonds.

C) High temperature is used repeatedly in PCR to denature the template DNA, or separate its strands.

D) High temperature is used to to break the covalent bonds that connect individual nucleotides to separate the DNA strands.

The correct answer is C high temperature is used repeatedly in PCR to denature the template DNA and separate its strands.

Explanation:

PCR or polymerase chain reaction is one the most significant application of moleular biology. PCR is used for amplification of target DNA molecule. PCR is carried out in thermal cycler.

There are 3 principle steps to carry out PCR

1 Denaturation it is done at very high temperature 95 degree centigrade. The DNA strands get separated from each other at this high temperature by a process called denaturation.

2 Renaturation it is done by lowering down the temperature to 55 degree centigrade so that the denaturated DNA strands can be annealed with each other.

3 DNA synthesis Addition of RNA primer at the 3" end of both strands along with the addition of deoxyribonucleotides and a thermostable DNA polymerase to carry out the synthesis of new DNA strands with respect to the template strands.