Biology 330 Exam II Review 2008

Biology 330 Exam II Review 2008 - Material for Exam II I....

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Material for Exam II I. Regulation of Gene (and/or Protein) Expression A. Know material on Regulation handout B. lac operon 1. Three structural genes: lac z, encodes β -galactosidase; lac y, encodes permease; lac a, encodes transacetylase 2. Transcription levels regulated between “low” and “high” by action of regulatory protein, LacI, that tries to block RNApol, by binding to the operator site, lac O (near the promoter). 3. Inducers (chemical signals) include several types of β -galactoside sugars: a.) Such as derivative of lactose, like Allolactose, and b.) “Gratuitous” inducers, like IPTG (that can’t be eaten by the bacterial cell); c.) Inducers bind to the regulatory protein (LacI), altering its conformation so that it cannot bind to the operator. C. Catabolite Repression 1. Effects of glucose on multiple operons at the same time. 2. Glucose blocks synthesis of cAMP. 3. For several operons (e.g., lac, gal, ara, mal ), cAMP must join with the Catabolite Activator Protein and bind to the CAP binding sites in each operon. 4. This helps RNApol bind to the promoters of each operon.
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Biology 330 Exam II Review 2008 - Material for Exam II I....

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