Starting with a single piece of dsDNA, after 3 PCR cycles there are
A) 2 additional pieces of dsDNA.
B) 4 additional pieces of dsDNA.
C) 8 additional pieces of dsDNA.
D) 16 additional pieces of dsDNA.
E) 1 additional piece of dsDNA.

Question

Quizplus · Accepted Answer

PCR (polymerase chain reaction) is a technique used to amplify a specific segment of DNA. In each cycle of PCR, the two strands of the template DNA are separated, and primers (short DNA sequences that bind to the template DNA) are annealed to each strand. DNA polymerase then synthesizes two new strands of DNA complementary to the template strands.

At the end of the first cycle, there are two copies of the target DNA sequence. At the end of the second cycle, there are four copies (each of the two copies from the first cycle has been replicated). At the end of the third cycle, there are eight copies (each of the four copies from the second cycle has been replicated). Therefore, the correct answer is C) 8 additional pieces of dsDNA.

Starting with a Single Piece of DsDNA, After 3 PCR