Question

With regard to mature $mRNA$ in eukaryotes

• A. exons and introns do not appear in the mature $RNA$
• B. exons appear but introns do not appear in the mature $RNA$
• C. introns appear but exons do not appear in the mature $RNA$
• D. both exons and introns appear in the mature $RNA$

Answer 1

Answer: (B)

Eukaryotic transcripts possess extra segments called introns or intervening sequences or noncoding sequences. They do not appear in mature or processed $RNA$. The functional coding sequences are called exons. Splicing is removal of introns and fusion of exons to form functional $RNAs$.