Question

Why is the mRNA not equal in length to the DNA it was transcribed from? 1) the mRNA was longer because it has a Poly A tail 2) The mRNA was longer because it contains only introns 3) The DNA was shorter because it does not have the Methylated cap 4) The mRNA was shorter because of Intron splicing

Answer 1

4) The mRNA was shorter because of Intron splicing

Step-by-step explanation:

In eukaryotic cells, the process of gene transcription uses a fragment of DNA as template in order to synthesize a complementary single-stranded RNA molecule known as primary messenger RNA transcript or 'pre-mRNA', which is then processed to yield a mature messenger RNA (mRNA). This mature mRNA is finally used as template to synthesize a polypeptide chain (i.e., a protein) by the process of translation. RNA splicing refers to the processing mechanism by which a pre-mRNA is transformed into a mature mRNA. During RNA splicing, non-coding regions of the pre-mRNA called 'introns' are removed, whereas the remaining coding regions called 'exons' are joined toghether to form a mature mRNA. In consequence, RNA splicing generates an mRNA that is shorter than the originally transcribed gene sequence.