RNA polymerase II primarily transcribes which class of RNA?

RNA polymerase II primarily transcribes which class of RNA?

• A. rRNA
• B. tRNA
• C. mRNA
• D. All of the above

Answer: (C)

The main idea is that different RNA polymerases in eukaryotes specialize in different RNA products. RNA polymerase II is the workhorse for making messenger RNA, the transcripts that carry genetic information from DNA to the ribosome to guide protein synthesis. It does produce some noncoding RNAs as well, but its primary product is mRNA. In contrast, ribosomal RNA is mainly transcribed by RNA polymerase I, and transfer RNA by RNA polymerase III. Because of that, the best answer is mRNA. The option that suggests all of the above would be inaccurate since rRNA and tRNA are not primarily transcribed by RNA polymerase II.

The main idea is that different RNA polymerases in eukaryotes specialize in different RNA products. RNA polymerase II is the workhorse for making messenger RNA, the transcripts that carry genetic information from DNA to the ribosome to guide protein synthesis. It does produce some noncoding RNAs as well, but its primary product is mRNA. In contrast, ribosomal RNA is mainly transcribed by RNA polymerase I, and transfer RNA by RNA polymerase III. Because of that, the best answer is mRNA. The option that suggests all of the above would be inaccurate since rRNA and tRNA are not primarily transcribed by RNA polymerase II.