Question

Choose the components that are required for the proper functioning of DNA polymerase enzyme.
(P) DNA template
(Q) A DNA primer
(R) An RNA primer
(S) Four different dNTPs

• A. Only (P), (Q) and (R)
• B. Only (P), (R) and (S)
• C. Only (Q), (R) and (S)
• D. Only (P), (Q) and (S)

Hint:

In PCR (in-vitro), we use DNA primers, but in the biological context of the enzyme's proper functioning in a cell, RNA primers are the standard requirement.

Answer 1

The Correct Option is B

The question requires identifying the components necessary for the proper functioning of the DNA polymerase enzyme. Let's go through the options provided to understand why the correct answer is "(P), (R), and (S)":

1. DNA Template (P): A DNA template is essential for DNA polymerase as it provides the sequence that needs to be copied. Without a template, the enzyme would have no guide for synthesizing new DNA strands.
2. DNA Primer (Q): While it is true that primers are required for DNA synthesis, DNA polymerase specifically relies on RNA primers, not DNA primers, in biological systems like within a cell during replication.
3. RNA Primer (R): RNA primers are necessary for DNA polymerases because they provide a starting point for addition of nucleotides. This primer has a free 3' hydroxyl group that enables the addition of new nucleotides.
4. Four Different dNTPs (S): Deoxyribonucleotide triphosphates (dNTPs) are the building blocks for new DNA strands. They are essential substrates that provide the nucleotides to be added by the DNA polymerase to the growing DNA chain.

From the analysis above, the correct components for the function of DNA polymerase are the DNA template (P), an RNA primer (R), and the four dNTPs (S).

Therefore, the correct answer is Only (P), (R) and (S).