Question

In eukaryotic cells, 5S rRNA genes are transcribed by _________________

-RNA polymerase II

-RNA polymerase III

-RNA polymerase V

-RNA polymerase I

-RNA polymerase IV

Answer 1

5S rRNA genes in eukaryotic cells are transcribed by RNA polymerase III. This enzyme also transcribes tRNA and small nuclear RNA genes, and it uses internal promoters within the transcribed sequence to initiate transcription.

Step-by-step explanation:

In eukaryotic cells, 5S rRNA genes are transcribed by RNA polymerase III. This particular polymerase is responsible for transcribing various small RNAs, which include 5S rRNA, tRNA, and small nuclear RNA genes. RNA polymerase I is tasked with transcribing the larger rRNA genes, while RNA polymerase II deals with all of the protein-coding genes. The transcription initiation for 5S rRNA involves unique promoter sequences that lie within the transcribed sequence itself. After binding these internal promoters with the help of initiation factors, RNA polymerase III re-positions itself to begin transcription at the correct start site.