In this lecture we're simply going to introduce the fact that in prokaryotic cells we don't have this process taking place but in eukaryotic cells we do have the process of mrname modification. So as soon as we synthesize that particular mRNA that mRNA is known as the primary mRNA, the precursor mRNA or the pre mRNA molecule. And it consists of these introns shown in green and the exons shown in blue. So let's call this exon number one, exxon number two and exxon number three. Now first we basically create these two modifications. We cap our five end and we basically add the polya tail on the other end of that particular mRNA molecule.