What processes are involved in RNA processing to convert the primary transcript into mature mRNA?

• A. Transcription termination and promoter recognition
• B. 5' capping, 3' polyadenylation, and intron/exon splicing
• C. RNA editing by base modifications only
• D. Nuclear export alone

Answer: (B)

RNA processing transforms a freshly made RNA transcript into a functional mRNA by adding protective and enabling features and by removing noncoding sequences. The essential steps are adding a 5' cap, adding a 3' poly(A) tail, and removing introns while joining exons. The 5' cap protects the transcript from degradation and helps the ribosome recognize the message during translation. The 3' poly(A) tail increases stability, supports export from the nucleus, and enhances translation efficiency. Splicing excises introns and links exons, and it also allows the generation of multiple protein variants through alternative splicing. Transcription termination and promoter recognition are parts of transcription rather than RNA processing, base modifications aren’t the general maturation steps for most mRNA, and nuclear export happens after processing rather than being a processing step itself. Together these processing events convert the primary transcript into a mature mRNA ready for export and translation.