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19 Cards in this Set
- Front
- Back
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supercoiled DNA |
DNA is further twisted to save space |
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Negative supercoiling |
double helix is underwound |
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positive supercoiling |
double helix is overwound |
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relaxed DNA |
number of turns predicted by number of base pairs |
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DNA gyrase |
catalyses DNA supercoiling |
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Plasmid |
replicate separately from chromosome, double-stranded DNA and circular DNA |
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Transposable elements |
segments of DNA that can move from 1 site to another on the same or different DNA molecules |
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Pribnow box |
located 10 bases before the start transcription (prokaryotes) |
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Operons |
a group of related genes costranscribed on a polycistronic mRNA, allows expression of multiple genes to be coordinated. |
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Homodimeric protein |
composed of 2 identical polypeptides. each bind to 1 inverted repeat. |
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negative transaction regulation |
blocks transcription |
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positive transcription regulation |
activates transcription |
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Global Control system |
regulates multiple gene expression simultaneously |
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Catabolic repression |
repressed in the presence of glucose. lac operon under control. |
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Diauxic growth |
2 exponential phases: 1. glucose growth 2. lactose growth |
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sensor kinase |
detects environmental signals and autophosphorylates |
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Chemotaxis regulation |
1. response to signal (MCPs bind yo attraction and initiate flagella rotation) 2. controlling flagella rotation (controlled by CheY protein) 3. Adaptation (feedback loop) |
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Quorum Sensing |
mechanism by which bacteria assess their population density |
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autoinducer |
bind to specific activator proteins and trigger transcription |
