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🔬 Biology  ·  Molecular Basis of Inheritance  ·  NEET

Which enzyme synthesises the short RNA primer needed for DNA replication?

Answer: Primase.

  • A Helicase
  • B Primase
  • C Ligase
  • D Topoisomerase

Correct answer: B. Primase

Explanation: Primase synthesises a short RNA primer complementary to the template, providing the free 3 prime end that DNA polymerase extends.

The Replication Forkhelicase (unwinds fork)leading strand (continuous, 5'→3')lagging strand: Okazaki fragments (discontinuous)

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.

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