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) amplifies DNA by doubling the number of copies each cycle, assuming 100% efficiency.
2. Recall the formula for the number of DNA copies after n cycles starting from one copy: \(\text{Number of copies} = 2^{n}\), where \(n\) is the number of cycles.
3. Substitute the given number of cycles (15) into the formula: \(\text{Number of copies} = 2^{15}\).
4. Calculate or estimate the value of \$2^{15}$ to determine the approximate number of copies produced after 15 cycles.
5. Compare the calculated number to the options provided (a few, a few hundred, a few thousand, millions) to select the correct answer.

Key Concepts

Polymerase Chain Reaction (PCR) Basics

PCR is a technique used to amplify a specific DNA segment exponentially by cycling through denaturation, annealing, and extension steps. Each cycle ideally doubles the number of DNA copies, leading to rapid accumulation of the target sequence.

Exponential Amplification in PCR

In PCR, the number of DNA copies doubles with each cycle, so after n cycles, the total copies equal 2^n. Starting with one copy, 15 cycles would produce 2^15 copies, illustrating the power of exponential growth in molecular biology.

Calculating PCR Product Quantity

To estimate the number of DNA copies after PCR, use the formula 2^n, where n is the number of cycles. For 15 cycles, 2^15 equals 32,768 copies, which corresponds to tens of thousands, helping to choose the correct answer from the options.