What are exons?

What are exons?

• A. Introns
• B. Coding segments that remain after splicing
• C. Promoters
• D. Noncoding segments

Answer: (B)

Exons are the parts of a gene that stay in the RNA after processing. In eukaryotes, the initial transcript (pre-mRNA) contains exons and introns. The spliceosome removes introns and joins the exons together, creating mature mRNA. The sequences in these exons are the coding portions that will be translated into protein (though exons can also include untranslated regions that remain part of the mature mRNA). So exons are the coding segments that remain after splicing. Introns are the parts removed, promoters are regulatory DNA sequences that initiate transcription, and noncoding segments is a vague description that doesn’t specify the retained, coding nature of exons.

Exons are the parts of a gene that stay in the RNA after processing. In eukaryotes, the initial transcript (pre-mRNA) contains exons and introns. The spliceosome removes introns and joins the exons together, creating mature mRNA. The sequences in these exons are the coding portions that will be translated into protein (though exons can also include untranslated regions that remain part of the mature mRNA). So exons are the coding segments that remain after splicing. Introns are the parts removed, promoters are regulatory DNA sequences that initiate transcription, and noncoding segments is a vague description that doesn’t specify the retained, coding nature of exons.