Which RNA polymerase is responsible for transcribing tRNA?

The correct answer recognizes that RNA polymerase III is specifically responsible for transcribing tRNA, along with other small RNA molecules such as 5S rRNA and snRNA. This polymerase plays a crucial role in synthesizing genes that are vital for the translation process, which involves converting mRNA into proteins with the help of tRNA.

Each type of RNA polymerase has distinct substrates it works with, which makes RNA polymerase III integral for the synthesis of tRNA, as tRNA is essential for the proper functioning of ribosomes during protein synthesis. Understanding the specific functions of each RNA polymerase is fundamental in molecular biology, as it underscores the organization and regulation of gene expression in eukaryotic cells.

In contrast, RNA polymerase I is primarily involved in the transcription of rRNA (except for 5S rRNA), RNA polymerase II transcribes mRNA and some snRNA, and RNA polymerase IV, which is found in plants, is associated with small interfering RNA (siRNA) to regulate gene expression. Each RNA polymerase fulfills unique roles in the transcriptional hierarchy, highlighting the division of labor among them in the cell.