16_questions_regulation

16_questions_regulation - mal operon promoter so that it...

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Study questions for Regulation 1) Why do organisms have so many genes if they don't even express them all at once? 2) How is the lac operon regulated? Why aren’t the lac genes always transcribed? How does the regulator work? What would happen to lac operon transcription if you moved the LacI operator sequence upstream of the -35 element? 3) How does tryptophan repress the genes for its own biosynthesis? Why does this happen? How would transcription/expression or the trp operon change in mutants that lack the TrpR repressor? 4) How is the trp operon different and similar to the mal operon? How could you change the
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Unformatted text preview: mal operon promoter so that it was repressed by the MalT activator? 5) The following graph shows a time course of glucose (solid line) and lactose (dashed line) concentrations of a culture of E. coli growing with both sugars. What type of regulation is occurring in this culture prior to lactose consumption? Why is glucose used up before lactose? What are the molecular events for this type of regulation of lactose metabolism? 5) How does FNR differ with and without oxygen? What would be the growth physiologies of an fnr mutant for nitrate, fumarate, DMSO, and oxygen respiration?...
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