Question

Exon segments are reunited after splicing by

• A. RNA primase
• B. DNA polymerase
• C. RNA polymerase
• D. RNA ligase

Answer 1

The correct option is D RNA ligase

RNA primase synthesizes RNA primer which is a stranded segment (complementary to the template) and has a free 3’ hydroxyl group to facilitate the addition of nucleotides by polymerase enzymes. RNA polymerase synthesizes RNA using DNA template strand by adding the ribonucleotides to a primer in 5' to 3' direction via phosphodiester bonds. Splicing is the removal of introns from the primary transcript and ligation of exons to form a continuous sequence specifying a functional polypeptide. RNA ligase enzyme joins two exons together via phosphodiester bond between 3’ hydroxyl at the end of one exon and a 5’ phosphate at the end of another exon. The correct answer is D.