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Published byNicholas White Modified over 8 years ago
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Prokaryotes vs Eukaryotes
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But first it’s QUIZ TIME!! Copier is down – deal with it 1.Write the correct mRNA transcript based on the gene sequence below: GTA GTA GGT 2. Use your codon chart to determine the sequence of amino acids dictated by the gene sequence above.
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mRNAAmino Acid AGA arginine GGA glycine AGC serine GCA alanine CAG glutamine 3. Which mRNA would code for both amino acid sequences shown, simply by a shift in the reading frame? …glutamine…glutamine…glutamine …serine… serine… serine A.AGUAGUAGUAGUC. GCUGCUGCUGCU B.AGCAGCAGCAGCD. GCAAGCGCAAGC
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Use the amino acid chart from question #3 …glycine…serine…glycine… 4.Which of the following DNA strands would code for the amino acid sequence shown above? A.ACTCCTTCTC. CCGTCGACT B.TCTCCGTCGD. CCTTCGCCT
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#5 and #6 5. An incoming tRNA would attach to which site on the ribosome? 6. If the tRNA anticodon is UUU, what amino acid will it bring to the growing peptide chain?
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#7 and #8 7.Spliceosomes cut out ______ and splice together ________ which get expressed. 8. Modifications to the ends of the mRNA transcript are required before leaving the nucleus. Which end (3’ or 5’) is modified with a Poly- A tail?
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II. RNA modification
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5’ cap chemically speaknig
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The movie – yes there is a movie http://vcell.ndsu.nodak.edu/animations/mr naprocessing/movie.htmhttp://vcell.ndsu.nodak.edu/animations/mr naprocessing/movie.htm
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Why Cap and Poly- A tail? Protect the messenger! exonucleases – protect but destroy http://en.wikipedia.org/wiki/5'_cap
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III Bacteria genetics Binary fission
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Prokaryotic variation in genetic make-up Mutations Genetic recombination –Transformation –Transduction –Conjugation
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Transformation
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Transduction
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Conjugation
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IV. Control of metabolic pathways A.Two ways 1.Vary the activity of the enzymes (inhibit them or promote their ability) – feedback inhibition pathways 2.Vary the # of enzymes present – regulate enzyme production at the gene expression level
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B. Gene regulation in bacteriaGene regulation in bacteria OPERONS! –Need to know that an operon is a section of DNA that contains genes for a protein –Need to know the parts and players
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Ex 1 – Lac Operon
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Ex 2 Tryptophan operon
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A closer look at the parts A) promoter – site on DNA where RNA polymerase can bind and begin transcription B) operator – the “on/off” switch, located between promoter and structural genes C) structural genes – genes that code for a protein
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Important players Repressor – a protein that when active will bind to the operator thus blocking transcription Regulatory gene – the DNA sequence that codes for the repressor protein Co-repressor – a molecule that attaches to an inactive repressor and makes it active Inducer – a molecule that attaches to an active repressor and makes it inactive
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How they work together Negative regulation Positive regulation
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Negative regulation Two examples –Lac operonLac operon –Tryptophan operon – best animation link everTryptophan operon
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