What occurs during the denaturation step of the PCR process?

During the denaturation step of the PCR process, the primary action is the separation of the DNA strands through the application of high temperatures. This heating causes the hydrogen bonds between the complementary bases of the DNA double helix to break, effectively "unzipping" the strands. Denaturation typically occurs at around 94-98 degrees Celsius, allowing the two strands to become single-stranded, which is essential for the subsequent steps in PCR, such as annealing of primers and extension.

This step is critical because it creates the necessary conditions for the primers to bind to their specific complementary sequences on the now-separated single-stranded DNA templates in the next stage of the cycle. The other options describe different processes or steps that occur either before or after denaturation and do not accurately reflect what happens during this particular step.