Question

Given below is a heterogeneous RNA formed during Eukaryotic transcription:
 
How many introns and exons respectively are present in the hnRNA?

• A. 7, 7
• B. 8, 7
• C. 8, 8
• D. 7, 8

Hint:

In eukaryotic hnRNA, introns are the non-coding regions between exons, and their number is typically one less than the number of exons in a linear sequence.

Answer 1

The Correct Option is D

Step 1: Heterogeneous nuclear RNA (hnRNA) in eukaryotes contains both exons (coding regions) and introns (non-coding regions) before processing into mature mRNA.
Step 2: The diagram $5' \sim \sim \sim \sim \sim 3'$ typically represents a sequence with alternating exons and introns. If the diagram implies 15 total segments (as a simplified representation), we interpret it as 8 exons (including the ends) and 7 introns (the segments between exons).
Step 3: This matches the pattern of eukaryotic transcription where introns are removed, leaving exons in the mature mRNA.
Thus, the hnRNA has 7 introns and 8 exons.