During eukaryotic DNA replication, which enzyme synthesizes the short RNA primer required to initiate leading and lagging strand synthesis?
Answer and explanation
Correct answer: D. DNA primase associated with DNA polymerase alpha
- Step 1: DNA polymerases cannot initiate polynucleotide synthesis de novo because they require an existing 3'-OH group. Step 2. DNA primase synthesizes a complementary RNA primer (approx. 10 nucleotides) providing the free 3'-OH terminus. Answer: DNA primase associated with DNA polymerase alpha. Why not the others: Ligase seals nicks, topoisomerase relieves torsional strain, and telomerase replicates chromosome ends.
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