Question

Which of the following enzymes is responsible for transcription of ribosomal RNA?

• A. RNA polymerase
• B. RNA polymerase I
• C. RNA polymerase II
• D. RNA polymerase III

Hint:

Remember: RNA polymerase I → rRNA, RNA polymerase II → mRNA, RNA polymerase III → tRNA.

Answer 1

The Correct Option is B

Step 1: Functions of RNA polymerases in eukaryotes.
- RNA polymerase I: Transcribes rRNA (except 5S rRNA).
- RNA polymerase II: Transcribes mRNA, snRNA, some miRNAs.
- RNA polymerase III: Transcribes tRNA and 5S rRNA.
Step 2: Analyzing options.
(A) RNA polymerase: General term, not specific.
(B) RNA polymerase I: Correct — Transcribes most ribosomal RNA.
(C) RNA polymerase II: Incorrect — Responsible for mRNA synthesis.
(D) RNA polymerase III: Incorrect — Transcribes tRNA and 5S rRNA.
Step 3: Conclusion.
Hence, RNA polymerase I is responsible for transcription of rRNA.