How many copies could PCR make if we started with one copy of a template and
performed 15 cycles of copying?
a. A few
b. A few hundred
c. A few thousand
d. Millions

Verified step by step guidance

1. Understand that PCR (Polymerase Chain Reaction) is a technique used to amplify DNA, meaning it makes many copies of a specific DNA segment.
2. Each cycle of PCR doubles the number of DNA copies. So, if you start with one copy, after one cycle, you have 2 copies; after two cycles, you have 4 copies, and so on.
3. The number of copies after n cycles can be calculated using the formula: \(2^n\), where n is the number of cycles.
4. Substitute the given number of cycles (15) into the formula to determine the number of copies: \(2^{15}\).
5. Calculate \(2^{15}\) to find the total number of copies after 15 cycles.

Key Concepts

Polymerase Chain Reaction (PCR)

PCR is a molecular biology technique used to amplify specific DNA sequences. It involves repeated cycles of denaturation, annealing, and extension, allowing for exponential replication of the target DNA. Each cycle doubles the amount of DNA, making it a powerful tool for genetic analysis and research.

Exponential Growth in PCR

In PCR, the amount of DNA increases exponentially with each cycle. Starting with one copy, after n cycles, the number of copies can be calculated using the formula 2^n. Therefore, after 15 cycles, the theoretical maximum would be 2^15, which equals 32,768 copies, illustrating the rapid amplification capability of PCR.

Limitations of PCR

While PCR can theoretically produce millions of copies, practical limitations exist, such as enzyme efficiency, reaction conditions, and the presence of inhibitors. These factors can affect the actual yield of DNA, but under optimal conditions, PCR can still generate millions of copies from a single template.