Question

RNA polymerase I catalyzes

• A. Elongation in transcription
• B. rRNA synthesis
• C. mRNA synthesis
• D. tRNA synthesis

Answer 1

The correct option is B rRNA synthesis

There are three types of nuclear RNA polymerases in eukaryotic cells. RNA polymerase I (Pol I) synthesizes only one type of RNA, a transcript called preribosomal RNA (or pre-rRNA). It contains the precursor for the 18S, 5.8S, and 28S rRNAs. RNA polymerase III (Pol III) synthesizes tRNAs, the 5S rRNA, and some other small specialized RNAs. RNA polymerase II (Pol II) synthesizes mRNAs and some specialized RNAs. It is the enzyme that add ribonucleotides to primer during elongation phase of transcription. Correct option is B.