chap_17-3

chap_17-3 - size transcript will form Keys to attenuation:...

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Chapter 17, Part III (of III) Prokaryotic Gene Regulation Brainstorm activity : Review lac operon and “create” the trp operon
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Gene expression controls metabolism Catabolism lactose glucose + galactose Anabolism precursors tryptophan What is a probable repression mechanism?
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Tryptophan is a ___________: Molecule that binds repressor and allows it to stop transcription What kind of protein is the repressor? ______________
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lacI mutants (flashback)
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tryptophan binding sites DNA binding sites
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Attenuation by alternative transcripts Attenuation =
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or trpE trpD trpC trpB trpA Attenuation by alternative transcripts Keys to attenuation: 1) Internal secondary structure of the mRNA transcript (specifically the #3 region)
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Simultaneous translation determines what
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Unformatted text preview: size transcript will form Keys to attenuation: 1)Internal secondary structure of the mRNA transcript 2)Simultaneous movement of Ribosome along transcript trpE trpD trpC trpB trpA 100 100 ? What mutation(s) would lead to 100% expression in the presence of trp? What other mutation(s) would affect expression? What is the benefit of attenuation? Why need it if the repressor turns transcription on and off? Fine-tuning the cell can sense the concentration of tryptophan via the trp tRNA level Do you think this type of attenuation mechanism occurs in eukaryotes? No. transcription and translation are not coupled. Transcription nucleus, translation cytoplasm....
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This note was uploaded on 02/03/2011 for the course BIOL 2153 taught by Professor Larkin during the Fall '03 term at LSU.

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chap_17-3 - size transcript will form Keys to attenuation:...

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