Question

Which of the following answer choices is not a valid type of mrna editing that occurs during the process of transcription?

A) addition of a 5’ cap to the 5’ untranslated region of the mrna strand

B) addition of a poly-A tail to the 3’ untranslated region of the mRNA strand

C) splicing together of Exon’s through rna processing

D) splicing together of introns through rna processing

Answer 1

D) splicing together of introns through rna processing

Step-by-step explanation:

Transcription is the process by which an mRNA molecule is synthesized using a DNA template. However, the initial mRNA transcript is considered pre-mRNA until it undergoes post-transcriptional processing to become matured. The mRNA processing involves three steps viz: capping of 5', polyadenylation and splicing.

The 5' end of the mRNA molecule is capped with a 5' cap in the first mRNA processing stage. This is followed by the addition of a poly(A) tail to the 3' end of the mRNA strand. The last step called Splicing involves removal of introns (non-coding regions of sequence) from the mRNA sequence while the remaining protein-coding regions called EXONS are joined or spliced together.

Hence, option D which says: splicing together of introns through rna processing is not correct because exons are spliced together during splicing step of mRNA processing.