Question

Select the statement that best describes the function of heating and cooling in PCR.

1) Heating and cooling in PCR helps to denature the DNA strands.
2) Heating and cooling in PCR helps to amplify the DNA strands.
3) Heating and cooling in PCR helps to separate the DNA strands.
4) Heating and cooling in PCR helps to visualize the DNA strands.

Answer 1

The heating and cooling in PCR serve different functions. Heating (denaturation) breaks the DNA strands apart, while cooling (annealing) allows primers to bond and initiate amplification.

Step-by-step explanation:

The heating and cooling in PCR serve different functions at each step of the process. The heating step, known as denaturation, involves heating the DNA to break the bonds holding the two strands together, resulting in two single strands of DNA. This is important for the separation of DNA strands. The cooling step, known as annealing, involves cooling the single strands of DNA and mixing them with short DNA segments called primers. The primers have base sequences that are complementary to segments of the single DNA strands, allowing them to bond and initiate the amplification of the DNA strands. Therefore, the statement that best describes the function of heating and cooling in PCR is option 3) Heating and cooling in PCR helps to separate the DNA strands and initiate DNA amplification.