Describe the role of RNA processing in creating mature mRNA in eukaryotes.

• A. Capping of the 5' end, splicing to remove introns, and polyadenylation at the 3' end generate stable, translatable mRNA.
• B. RNA processing converts mRNA to tRNA.
• C. Polyadenylation at the 5' end only; splicing not involved.
• D. Capping at the 3' end only; introns are retained.

Answer: (B)

RNA processing in eukaryotes creates mature mRNA through three coordinated steps: adding a 5' cap, removing introns by splicing, and adding a poly-A tail at the 3' end. The 5' cap protects the transcript and helps the ribosome recognize and initiate translation. Splicing removes noncoding introns and joins the remaining exons to form a continuous coding sequence. The poly-A tail increases stability and enhances translation efficiency, while also aiding export from the nucleus. Altogether, these modifications produce a stable, translatable mRNA ready for export to the cytoplasm. Note that RNA processing does not convert mRNA into tRNA; tRNA is produced and processed through its own distinct pathway.