BY 108 Chapter Notes - Chapter 15: Rna Splicing, Alternative Splicing, Noncoding Dna
Document Summary
Introns - intervening sequences found in eukaryotic dna. Noncoding dna that doesn"t show up in mrna or proteins. Rna splicing - cuts apart primary transcript to make final mrna. Occurs in nucleus, before mrna goes into cytoplasm. Spliceosome - large complex of snrnps removes introns by twisting them in lariat shape. Exon-shuffling - theory that intron-exon arrangements represent shuffling of functional units over time alternative splicing - splicing primary transcript into many mrnas includes different sets of exons. Makes 120,000 different mrnas possible in human cells. Proteomics - study of proteins differences between prokaryotic/eukaryotic gene expression. Eukaryotic genes have introns, prokaryotic genes don"t. Prokaryotic mrna contain transcripts for many genes, eukaryotic mrna only contain transcript for 1 gene. Prokaryotes can start translation before transcription is done (no nucleus) 5" cap and 3" poly-a tail added to genes by eukaryotes. 5" cap starts translation in eukaryotes, aug codon starts translation in prokaryotes.
