Question

You have selected your two primers and added all of the PCR components to a test tube. Use the answer choices [A-C] to explain what will happen as the polymerase chain reaction proceeds. Answers may be used more than once or not at all.

Answer 1

Hi. You did not provide any response options. However, a PCR reaction proceeds as follows.

After the primers are added to the test tube containing the PCR components. This tube is placed in a device called a thermocycler. At that moment, the stage called denaturation will begin, where the thermocycler increases the temperature to the point of breaking the hydrogen bonds that hold the two strands of DNA together. The thermal cycler increases the temperature up to 96°C.

After that, the second step of the reaction begins. At that moment, the thermal cycler lowers the temperature to 55º - 65ºC, which is the ideal temperature for the primers to be able to attach themselves to the DNA strands, preparing them for the presence of the polymerase.

After that, the thermocycler raises the temperature to 72ºC, which is the ideal temperature for the DNA polymerase to work. At this stage, the DNA polymerase will use the DNA strand and the primer to build a new DNA strand, which will be annealed to the DNA strand used as a template.

These three steps will be repeated about 35 times, generating many copies of DNA.