Polymerase Chain Reaction (PCR) Cycle Explained

What is the correct order for one cycle of polymerase chain reaction (PCR)?

Which of the following is in the correct order for one cycle of polymerase chain reaction (PCR)?

A. Extend primers; anneal primers; denature DNA.

B. Denature DNA; add fresh enzyme; anneal primers; add dNTPs; extend primers.

C. Denature DNA; anneal primers; extend primers.

D. Add fresh enzyme; denature DNA; anneal primers; add dNTPs; extend primers.

E. Anneal primers; denature DNA; extend primers.

Answer:

Denature DNA; anneal primers; extend primers.

The correct order of one cycle of Polymerase Chain Reaction (PCR) is: Denature DNA; anneal primers; extend primers. This process involves heating the DNA to separate it, adding primers to the separate strands, and then extending the DNA sequence with nucleotides.

Explanation:

The proper order of steps in one cycle of Polymerase Chain Reaction (PCR) is: Denature DNA; anneal primers; extend primers. The PCR cycle starts with denaturation, where the DNA template is heated to separate the double strands. Following the denaturation, the temperature is lowered to allow primers to anneal (stick) to the DNA strands. These primers are short pieces of DNA that are complementary to each end of the target sequence. Finally, the temperature is raised for the extension phase. In this phase, heat-stable DNA polymerase adds nucleotides to the primers, extending the DNA sequence.