So not all regions of the premrname molecule code for our protein or proteins. Those regions that do code for the proteins are known as exons and those regions that do not code for the protein are known as introns. And so special types of enzymes that together are known as the splicosome basically remove our introns and split together or combine or glue our exons and we form the final mRNA molecules. So basically to see what we mean, let's take a look at the following diagram. So let's suppose this is our precursor mRNA that now contains the polyatail that is shown here and it also contains the five guanosine triphosphate cap. Now, before our pre mRNA actually becomes the mRNA and is able to leave the nucleus, the final process that has to take place is the following.