The primary transcript in the nucleus of a eukaryotic cell is a messenger RNA but it is not yet functional. There will still be non-coding parts of the mRNA that needs to be removed (introns) and then coding parts must be spliced together (exons). After which, there is capping of the mRNA (5' or 5 prime capping) with 7-methylguanylate. There will also be adding multiple adenine residues in the 3' end of the mRNA called polyadenylation resulting to a poly-A tail at the 3' end of the mRNA. mRNA with spliced exons, a 5' cap, and a poly-A tail is now a functional RNA.