In PCR, what provides the primer binding sites for DNA amplification?

In PCR, what provides the primer binding sites for DNA amplification?

• A. The DNA template contains the binding sites by sequence
• B. The polymerase binds to DNA
• C. The dNTPs provide the binding sites
• D. The primers themselves provide the binding sites for initiation of synthesis

Answer: (D)

Primers determine where PCR starts by binding to complementary sequences on the DNA template. When they anneal, each primer provides a free 3' end for DNA polymerase to extend, anchoring the new strand. With two primers flanking the target region, they define both ends of the amplified product. So the primers themselves establish the binding sites for initiation of synthesis; the polymerase and nucleotides enable synthesis, but they do not establish where it begins.

Primers determine where PCR starts by binding to complementary sequences on the DNA template. When they anneal, each primer provides a free 3' end for DNA polymerase to extend, anchoring the new strand. With two primers flanking the target region, they define both ends of the amplified product. So the primers themselves establish the binding sites for initiation of synthesis; the polymerase and nucleotides enable synthesis, but they do not establish where it begins.