What does PCR do in molecular biology?

What does PCR do in molecular biology?

• A. Amplifies a specific DNA sequence through repeated cycles of heating and cooling with DNA polymerase.
• B. Sequences an entire genome.
• C. Transcribes RNA from DNA.
• D. Translates RNA into protein.

Answer: (A)

PCR amplifies a specific DNA sequence by cycling through heating and cooling with a DNA polymerase. When heated, DNA strands separate; cooling allows short DNA primers to bind to the ends of the target region; the polymerase then extends from these primers to build new copies. Each cycle roughly doubles the amount of target DNA, so after many cycles you get a large amount of the chosen sequence. The primers define exactly which region is copied, and a heat-stable enzyme is used to survive repeated cycles. This is not sequencing an entire genome, nor transcription of DNA to RNA, nor translation of RNA into protein.

PCR amplifies a specific DNA sequence by cycling through heating and cooling with a DNA polymerase. When heated, DNA strands separate; cooling allows short DNA primers to bind to the ends of the target region; the polymerase then extends from these primers to build new copies. Each cycle roughly doubles the amount of target DNA, so after many cycles you get a large amount of the chosen sequence. The primers define exactly which region is copied, and a heat-stable enzyme is used to survive repeated cycles. This is not sequencing an entire genome, nor transcription of DNA to RNA, nor translation of RNA into protein.