Answer: DNA ligase.
- A DNA polymerase
- B RNA polymerase
- C DNA ligase
- D Topoisomerase
Correct answer: C. DNA ligase
Explanation: DNA ligase seals the nicks between adjacent Okazaki fragments, joining them into a continuous lagging strand.
Helicase unwinds the double helix at the replication fork; one new strand (leading) is synthesised continuously toward the fork, while the other (lagging) must be made in short, separate Okazaki fragments because DNA polymerase only adds nucleotides 5'→3'.
Concept context
DNA structure, replication, transcription, translation, the genetic code, and gene regulation (lac operon). The single most important chapter for NEET molecular biology.