What stage allows for DNA strands to become single stranded in the PCR process?

In the PCR (Polymerase Chain Reaction) process, the denature stage is crucial because it is the step where the double-stranded DNA is heated to a high temperature, typically around 94-98 degrees Celsius. This high temperature causes the hydrogen bonds between the complementary bases of the DNA strands to break, resulting in the separation of the two strands into single strands of DNA. This single-stranded DNA is essential as it provides the template for the next stages of PCR, allowing for the specific amplification of a target DNA sequence in subsequent steps, such as annealing and extension.

The other stages of PCR serve different purposes: the annealing stage involves the binding of primers to the single-stranded DNA, while the extension stage is when DNA polymerase synthesizes new DNA strands by extending from the primers. The replication stage is not a technical term commonly used in the context of PCR.