Exons and Introns
Introns and Exons Exons: coded regions of DNA that get transcribed and translated into proteins make up 5% of the genome
Introns and Exons Introns: non-coded regions of DNA Must be removed before transcription
Introns and Exons Introns are removed by snrna and proteins called snrnp s (snurps)
Introns and Exons Introns are removed by snrna and proteins called snrnp s (snurps) snrnp s recognize intons and bind to them
Introns and Exons Introns are removed by snrna and proteins called snrnp s (snurps) snrnp s recognize introns and bind to them snrnp s interact to form an enzyme called a splicosome that removes introns
Introns and Exons There is no quality control in splicing out introns, so errors in replication are not removed
DNA in Prokaryotes vs Eukaryotes
DNA in Eukaryotes DNA in Prokaryotes -Located in the nucleus
DNA in Eukaryotes DNA in Prokaryotes -Located in the nucleus -Highly compact due to it s association with histones (proteins) and it s formation of nucleosomes (DNA wrapped around a protein)
DNA in Eukaryotes DNA in Prokaryotes -Located in the nucleus -Highly compact due to it s association with histones (proteins) and it s formation of nucleosomes (DNA wrapped around a protein) -Eventually becomes so compacted that it forms chromosomes
DNA in Eukaryotes -Located in the nucleus -Highly compact due to it s association with histones (proteins) and it s formation of nucleosomes (DNA wrapped around a protein) -Eventually becomes so compacted that it forms chromosomes DNA in Prokaryotes -DNA is circular and double stranded
DNA Replication Similarities between prokaryotic and eukaryotic replication Elongation starting to build at the 5 end (moves from 3 5 on parent strand) Have leading and lagging strand Require a primer to join Okasaki fragments Use DNA Polymerase
Replication in Eukaryotes Replication in Prokaryotes -Uses a variety of DNA polymerases -Thousands of origins of replication
Replication in Eukaryotes Replication in Prokaryotes -Uses a variety of DNA polymerases -Thousands of origins of replication
Replication in Eukaryotes Replication in Prokaryotes -Uses a variety of DNA polymerases -Thousands of origins of replication -Telomeres: Repeating sequences of DNA that prevent genetic information from being lost
Replication in Eukaryotes -Uses a variety of DNA polymerases -Thousands of origins of replication -Telomeres: Repeating sequences of DNA that prevent genetic information from being lost Replication in Prokaryotes -Rate of replication faster -One origin of replication
Transcription in Eukaryotes -Require a 5 cap of guanine nucleotides and a 3 poly-a tail added before translation happens Transcription in Prokaryotes
Transcription in Eukaryotes -Require a 5 cap of guanine nucleotides and a 3 poly-a tail added before translation happens Transcription in Prokaryotes -Transcription and translation happen simultaneously -No introns and exons, don t have to be removed
Gene Regulation
Genes have the ability to turn on and off, allows proteins to be made only when needed
Gene Regulation in Eukaryotes There are 5 levels of gene regulation in eukaryotes Pre-transcriptional Transcript ional Post-transcriptional Translat ional Post-translation
Gene Regulation in Eukaryotes 1) Pre-transcriptional Condensed nucleosome prevents transcription In areas that need to be expressed, nucleosome will loosen
Gene Regulation in Eukaryotes 2) Transcriptional Transcription factors (proteins) must interact with the promotor region to allow RNA polymerase to bind
Gene Regulation in Eukaryotes 3) Post-transcriptional mrna undergoes modifications as it leaves (introns removed, 5 cap and 3 tail added)
Gene Regulation in Eukaryotes 4) Translational RNA Interference: Use mirna(microrna) and sirna(small interfacing RNA) to inhibit gene expression by degrading RNA or inhibiting translation
Gene Regulation in Eukaryotes 5) Post-translational Controls time at which a protein becomes functional Ongoing: Never turn off Inducible: Only turn on when needed