So this is the mRNA that has not yet undergone the necessary modification processes that are needed for the molecule to exit the nucleus and enter the cytoplasm. And there are three important types of post transcriptional modifications. So we have the addition of the five guanosine triphosphate cap, we have the polyadenylation of the three N tail and we have the splicing of our axons and the removal of our introns. So let's take a look at each one of these post transcriptional modifications of the mRNA and see what they are and why they actually take place. And let's begin with the addition of the five and guanosine triphosphate cap. So within the nucleus of the cell, before our pre mRNA actually leaves the nucleus the five end of the precursor mRNA is altered by the attachment or the addition of a guanacine nucleotide via a special type of bond, a special type of linkage known as the five to five triphosphate linkage.