Gene Expression

Gene Expression - Gene Expression/Test 3 Tuesday, March 03,...

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Gene Expression/Test 3 Tuesday, March 03, 2009 9:30 AM 1. Helicase molecule o Protein made on ribosome o In cytoplasm. Sometime cell needs sometime cell doesn’t 2. Hemoglobin o Sometimes made sometimes not o In bone marrow 3. Control of Gene Expression 4. Why? o Only way going to get different cells 5. Where? o Different genes expressed according to what is needed in that cell. o What is the signal in nose as compared to the liver. 6. When? 7. Flow Chart--Pipes and valves o DNA unpacking DNA must unravel so accessible for transcription o Transcription Copy of information that was on DNA o Addition of Cap and Tail Helps RNA get directed to particular locations in cell o Splicing o RNA leaves nucleus o Transcript goes to ribosome. Sometimes broken down before reaching ribosome. Hemoglobin takes several genes to make a molecule 8. Transcripts are Edited o In eukaryote cells, m-RNA has a cap and tail added o Some parts are removed (introns) and others remain to be expressed (exons) o Protein that had 100 amino acids
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300 bases o Introns cut out by particular enzyme o DNA shown in loops Way to find location of molecules of proteins 9. To find proteins o Figure out amino acid o Separate the gene which corresponds o Use radioactivity 10.Genome and genes are different 11.Splicing o Alternative splicing may make more products 12.Control of Gene Expression:Prokaryotes o Operons (sequence of genes operating together) o Lac Operon Several genes=switch/control Breaks down lactose Only needs enzymes to break down food available (lactose) RNA polymerase Needed to make mRNA Cant make mRNA because protein is stuck on switch part that prevents transcription from happening When lactose is present, binds with protein and the protein doesn’t fit and turn switch off, the RNA polymerase can make enzyme that breaks down milk sugar. When lactose is gone gene can turn off again When lactose present, enzyme for breaking down is needed Secret to turning gene off Presence or absence of protein Binding of protein to region of DNA True in Eukaryotes as well Commonly done by adding molecular group to DNA 13.If gene is expressed it is transcribing 14.All the cells in your body have the same genetic information, but they come out differently o Zygote looks homogeneous o Control of gene expression causes each cell to come out different o Cell in liver does different things at different times 15.Most of molecular genetics research started in bacteria. o
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Gene Expression - Gene Expression/Test 3 Tuesday, March 03,...

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