What happens to introns in eukaryotic mRNA during RNA processing?

• A. They are spliced out and removed from the mRNA.
• B. They are left intact and become part of the mature mRNA.
• C. They are translated into proteins.
• D. They are converted into exons.

Answer: (A)

Verified step by step guidance

1. Understand the structure of eukaryotic genes: Eukaryotic genes consist of exons and introns. Exons are sequences that code for proteins, while introns are non-coding sequences.
2. Learn about RNA processing: After transcription, the pre-mRNA undergoes processing to become mature mRNA. This involves several modifications, including splicing.
3. Explore the splicing mechanism: During splicing, introns are removed from the pre-mRNA. This process is carried out by a complex called the spliceosome, which recognizes specific sequences at the intron-exon boundaries.
4. Recognize the outcome of splicing: Once introns are spliced out, the remaining exons are joined together to form the mature mRNA, which is then ready for translation into proteins.
5. Clarify the fate of introns: Introns are not translated into proteins, nor are they converted into exons. They are simply removed during the splicing process and do not become part of the mature mRNA.