Final answer:
Polyadenylation and splicing are both processes that take place in the nucleus of eukaryotic cells. They involve the removal of introns and the addition of a poly-A tail to pre-mRNA, resulting in a mature mRNA molecule ready for protein synthesis.
Step-by-step explanation:
Polyadenylation and splicing are essential processes that occur during the post-transcriptional modification of mRNA within the nucleus of eukaryotic cells. During splicing, non-coding regions called introns are removed from the pre-mRNA by a complex of enzymes known as the spliceosome. The remaining coding sequences called exons are then ligated together to form a mature mRNA molecule. Concurrently, polyadenylation involves the addition of a poly-A tail to the 3'-end of the mRNA, which signals the end of the molecule, aids in its export from the nucleus, and protects it against enzymatic degradation.
The mature mRNA, after being processed with a 5'-cap and a 3'-poly-A tail in addition to splicing, is then exported out of the nucleus and into the cytoplasm where it can be translated into protein by ribosomes. This regulated process ensures that the mRNA is appropriately modified and stable enough for efficient protein synthesis.