<Table> <Tr> <Td> Regulatory sequence Regulatory sequence Enhancer / silencer Promoter 5'UTR Open reading frame 3'UTR Enhancer / silencer Proximal Core Start Stop Terminator Transcription DNA Exon Exon Exon Intron Intron Post-transcriptional modification Pre - mRNA Protein coding region 5'cap Poly - A tail Translation Mature mRNA Protein The structure of a eukaryotic protein - coding gene . Regulatory sequence controls when and where expression occurs for the protein coding region (red). Promoter and enhancer regions (yellow) regulate the transcription of the gene into a pre-mRNA which is modified to remove introns (light grey) and add a 5' cap and poly - A tail (dark grey). The mRNA 5' and 3' untranslated regions (blue) regulate translation into the final protein product . </Td> </Tr> </Table> <Tr> <Td> Regulatory sequence Regulatory sequence Enhancer / silencer Promoter 5'UTR Open reading frame 3'UTR Enhancer / silencer Proximal Core Start Stop Terminator Transcription DNA Exon Exon Exon Intron Intron Post-transcriptional modification Pre - mRNA Protein coding region 5'cap Poly - A tail Translation Mature mRNA Protein The structure of a eukaryotic protein - coding gene . Regulatory sequence controls when and where expression occurs for the protein coding region (red). Promoter and enhancer regions (yellow) regulate the transcription of the gene into a pre-mRNA which is modified to remove introns (light grey) and add a 5' cap and poly - A tail (dark grey). The mRNA 5' and 3' untranslated regions (blue) regulate translation into the final protein product . </Td> </Tr> <Table> <Tr> <Td> Polycistronic operon Regulatory sequence Regulatory sequence Enhancer Enhancer / silencer / silencer Operator Promoter 5'UTR ORF ORF UTR 3'UTR Start Start Stop Stop Terminator Transcription DNA RBS RBS Protein coding region Protein coding region mRNA Translation Protein The structure of a prokaryotic operon of protein - coding genes . Regulatory sequence controls when expression occurs for the multiple protein coding regions (red). Promoter, operator and enhancer regions (yellow) regulate the transcription of the gene into an mRNA . The mRNA untranslated regions (blue) regulate translation into the final protein products . </Td> </Tr> </Table> <Tr> <Td> Polycistronic operon Regulatory sequence Regulatory sequence Enhancer Enhancer / silencer / silencer Operator Promoter 5'UTR ORF ORF UTR 3'UTR Start Start Stop Stop Terminator Transcription DNA RBS RBS Protein coding region Protein coding region mRNA Translation Protein The structure of a prokaryotic operon of protein - coding genes . Regulatory sequence controls when expression occurs for the multiple protein coding regions (red). Promoter, operator and enhancer regions (yellow) regulate the transcription of the gene into an mRNA . The mRNA untranslated regions (blue) regulate translation into the final protein products . </Td> </Tr>

In eukaryotes name 3 types of modifications that occur to pre-mrna and explain their function