Nucleic acids and protein synthesis: describe question

In a eukaryotic cell, a gene coding for the protein cytokeratin contains several introns and exons. The primary transcript is synthesised during transcription and then processed in the nucleus before it can be used for translation. Describe why the removal of introns from the primary transcript is necessary before translation can produce a functional polypeptide. In your answer, include the roles of the relevant molecules and structures involved in transcription, RNA processing, and translation.