Question

The device required for PCR is called thermal cycler. How many copies of the DNA segments are produced at the end of 9 cycles in an automatic thermal cycler?

• A. 18.
• B. 9.
• C. 128.
• D. 512.

Hint:

Each PCR cycle doubles the DNA, so the copies after n cycles are 2 to the power n.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept
In each PCR cycle (denaturation, annealing and extension) the amount of DNA doubles.

Step 2: Calculation
Starting with one DNA segment, the number of copies after \(n\) cycles is \(2^{n}\).
For 9 cycles: \(2^{9} = 512\).

Step 3: Compare the options
512 is the fourth option.

Final Answer:
512 copies are produced after 9 cycles. \[ \boxed{\text{(D) }512} \]