Refer to the figure associated with this question. The mRNA is smaller than the length of the DNA that codes for it because ________.
A) the regulatory regions (exons) of the gene are not transcribed
B) post-transcriptional modification removes the introns
C) post-transcriptional modification removes the exons
D) bases are added to the tail of the primary transcript

Question

Refer to the figure associated with this question. The mRNA is smaller than the length of the DNA that codes for it because ________.
A) the regulatory regions (exons) of the gene are not transcribed 
B) post-transcriptional modification removes the introns 
C) post-transcriptional modification removes the exons 
D) bases are added to the tail of the primary transcript

Quizplus · Accepted Answer

Post-transcriptional modification removes the introns, leaving only the coding regions (exons) in the final mRNA molecule. This is why the mRNA is smaller than the length of the DNA that codes for it.

Refer to the Figure Associated with This Question