Choose the correct pair from the following
- Exonucleases – Make cuts at specific positions within DNA
- Ligases – Join the two DNA molecules
- Polymerases – Break the DNA into fragments
- Nucleases – Separate the two strands of DNA
Answer
(2) Ligases – Join the two DNA molecules
Solution
As per NCERT:
Exonucleases remove nucleotides from the ends of the DNA, while endonucleases make cuts at specific positions within the DNA.
DNA ligases join the DNA fragments (two DNA molecules) together.
Polymerases synthesise (polymerise) nucleic acids; they do not break DNA.
Nucleases break the phosphodiester bonds of nucleic acids; strands are separated by heat (denaturation) or helicase.
∴ The correct pair is (2).
Answer: (2)