Final answer:
PCR requires specific temperature changes to occur successfully. Without the proper heating, there would be no amplification, because the necessary denaturation, annealing, and extension phases are temperature-dependent. A wrong annealing temperature affects primer binding and can result in reduced or failed DNA amplification.
Step-by-step explanation:
If the PCR system fails to heat up and remains at room temperature for the duration of the PCR reaction, the outcome would be no amplification of the DNA sequence. This is because the heat is required in the initial denaturation step to separate the double-stranded DNA, which must occur before the primers can bind to the single-stranded DNA in the annealing step. Moreover, the high temperature is also critical for the activity of the DNA polymerase enzyme in the extension step. Without these temperature changes, the three fundamental steps of PCR, which include denaturation, annealing, and extension, cannot occur, and thus the process cannot proceed to multiply the DNA fragment.
In the scenario of having the annealing temperature erroneously set to 65 °C instead of the intended 50 °C, this would negatively affect primer binding since primers are designed to anneal optimally at a specific temperature. The higher-than-optimal annealing temperature may reduce the efficiency of primer annealing, potentially leading to decreased or even failed DNA amplification.