Question

Question: Would you expect spliceosome-catalyzed intron removal to be reversible in a highly purified in vitro system and in vivo?

Short answer

The degradation of the excised introns in vivo makes this reaction irreversible. In vitro reaction is though reversible due to presence of introns.

Step-by-step solution

Significance of introns

The non coding segments called as introns is removed from the mRNA to make it in its active hnRNA for the process of translation This is called self splicing. Presence of introns is must to make this reaction reversible.

Explanation

For the process of self splicing,there is no requirement of any free energy input . Also there is no loss of any phosphodiester bonds. Self splicing reaction catalysed by spliceosome is reversible when carried out in vitro.When this reaction occurs in vivo , then the cut introns are degraded and hence the reaction cannot be reversed.