Question

DNA replication requires which of the following enzymes?

• A. DNA polymerase only
• B. DNA polymerase and ligase
• C. Ligase only
• D. RNA polymerase

Answer 1

The correct option is B

DNA polymerase and ligase

The correct option is B.

Explanation of correct option:

1. The biological process by which two identical DNA (deoxyribonucleic acid) replicas are generated from a single original molecule of DNA is called DNA replication.
2. One of the prime molecules used in the process of DNA replication is DNA polymerase.
3. DNA polymerases synthesize the DNA, it supplements DNA to the developing chain of DNA one by one, with only those complementing the template.
4. Apart from this, other enzymes like DNA ligase also play an essential role in the process of DNA replication.
5. The integrity of DNA is maintained by DNA ligase, that is, by joining the breaks in the phosphodiester bonds of DNA, which take place at the time of recombination and replication.

Explanation of incorrect options:

Option A:

1. In the process of DNA replication, apart from DNA polymerase, many enzymes play an important role like DNA ligase, DNA helicase, and topoisomerase.
2. In the process of DNA replication, DNA helicases separate double-stranded DNA into single strands, thus, permitting each strand to be copied.

Option C:

1. In the process of DNA replication, apart from DNA ligase, many enzymes play an essential role like DNA polymerase, DNA helicase, and topoisomerase.

Option D:

1. RNA polymerase has no role in the process of DNA replication.
2. It is an enzyme, which is accountable for copying a sequence of DNA into the sequence of RNA (ribonucleic acid) at the time of transcription.

Final answer: DNA replication requires both DNA polymerase and ligase.