Which enzyme is responsible for synthesizing a short complementary RNA primer required to initiate DNA replication?
Answer and explanation
Correct answer: C. RNA Primase
- Step 1: DNA polymerases cannot initiate polynucleotide synthesis de novo and require a free 3'-OH group. Step 2. RNA primase (an RNA polymerase) synthesizes an 8-12 nucleotide RNA primer providing the free 3'-OH end. Answer: RNA Primase. Why not the others: DNA helicase unwinds the double helix; DNA ligase seals phosphodiester nicks; topoisomerase relieves supercoiling tension.
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