During processing of a newly synthesized eukaryotic mRNA, which statement describes a step in maturation?

• A. A cap is added to the 5' end
• B. Introns are removed from the coding region
• C. A poly-A tail is added to one end of the molecule
• D. The mRNA is translated after processing

Answer: (C)

During maturation of a eukaryotic mRNA, the transcript is processed to become stable and export-ready, including adding a poly-A tail to the 3' end. This polyadenylation step is a hallmark of maturation: it protects the mRNA from degradation, helps export from the nucleus, and enhances translation efficiency in the cytoplasm. While adding a 5' cap and removing introns are also part of processing, the phrasing here points to the poly-A tail as the defining maturation event described. Translation occurs after processing, not during it. The intron-removal statement is conceptually about splicing, but the wording about the coding region is imprecise.