Genetics5 - # 6 7 2 0 0 3 F in a l E x a m MDCB 1A Final...

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Co In E MDCB 1A Final Exam Friday July 31st 4-7 pm Chem 1179 Exam = cumulative (everything) 150 pts Students with last names A to C Please proceed to PHELPS 1260 Bring blue scantron and ID Co In E #67 2003 Final Exam ! " Co In E Figure 13.19 Two states of the lac Operon: Lactose absent Co In E Figure 13.19 Two states of the lac Operon: Lactose present # $
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Co In E Inducible system = turn on when needed Repressible system = switch off due to accumulation of end products eg. Tryptophan synthesis The trp operon controls the synthesis of tryptophan Repressor protein + corepressor = inhibition Co In E Figure 13.20 The trp Operon: A Repressible System Co In E Figure 13.20 trp Operon: A Repressible System Co In E Animation 13.2 The trp Operon $ %
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Co In E Difference between inducible and repressible systems Inducible system = substrate binds repressor = R cannot bind operator = transcription on Usually controls catabolic pathways. Turned on only when substrate is available Repressible system = product = corepressor Interacts with R to bind operator = blocks transcription Usually control anabolic pathways which are turned off until product becomes unavailable Co In E Protein synthesis can be controlled By increasing promoter efficiency Transcription Is Enhanced by the Binding of the CRP-cAMP Complex to the Promoter. Co In E Figure 13.21 Transcription Is Enhanced by the Binding of the CRP-cAMP Complex to the Promoter. Catabolite Repression: When preferred carbon source is available (glucose), other operons related to carbon utilization do not transcribe at high rate. The lac operon is highly expressed only when: - glucose, + lactose $ % Co In E Catabolite Repression When glucose is abundant, cAMP levels drop. The CRP–cAMP complex does not form. Without the CRP–cAMP complex, RNA polymerase cannot bind to the promoter efficiently. The lac structural genes are transcribed at a very low level (almost off). This is called catabolite repression . $ ’
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Co In E Positive and Negative Control of lac Operon $ " Co In E The Eukaryotic Genome and its Expression (Chapt 14) • Eukaryotic genomes are larger than those of prokaryotes. • Much of eukaryotic DNA is noncoding.
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This note was uploaded on 10/08/2010 for the course MCDB MCDB 1A taught by Professor Senghuilow during the Summer '09 term at UCSB.

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Genetics5 - # 6 7 2 0 0 3 F in a l E x a m MDCB 1A Final...

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