BIOL 261 Lecture Notes - Lecture 11: Lac Repressor, Lac Operon, Repressor
30 Nov 2016
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Chapter 11: 1, 2, 3, 4,9, 10, 12, 19. Chapter 11: compare the structure of iptg with the structure of galactose. Ans: iptg is bound by the lac repressor because it has similar structure to lactose. Ans: promoter mutations cluster around the -10 and -35 positions because these are the dna sequences recognized and bound by the sigma subunit of the polymerase. Alterations to these sequences will affect the ability of the rna polymerase holoenzyme to recognize the promoter: note the large overlap between the operator and the region of the lac operon that is transcribed. Ans: oc mutants are changes in the dna sequence of the operator that impair the binding of the lac repressor. Therefore, the lac operon associated with the oc operator cannot be turned off. Using the conventional gene symbols for the lac operon, designate each genotype in the table. Ans: explain the fundamental differences between negative control and positive control of transcription in prokaryotes.
