Which RNA processing steps occur in eukaryotes after transcription?

• A. 5' capping, 3' polyadenylation, and splicing to remove introns.
• B. tRNA charging.
• C. DNA replication.
• D. Protein glycosylation.

Answer: (A)

RNA maturation in eukaryotes requires processing of the nascent transcript into a functional mRNA. The essential steps are adding a 5' cap early in processing, splicing out introns and joining exons, and adding a 3' poly(A) tail. The 5' cap helps protect the transcript and guides ribosome binding; splicing removes noncoding regions and allows different exon combinations (including alternative splicing) to generate diverse proteins; the poly(A) tail increases stability, aids export from the nucleus, and enhances translation. In contrast, tRNA charging is part of tRNA aminoacylation during translation, DNA replication is genome duplication, and protein glycosylation is a post-translational modification after protein synthesis. Therefore, the processing steps that occur after transcription are 5' capping, splicing, and 3' polyadenylation.