Notes 10-10-08

Notes 10-10-08 - Cyclic amp works with CAP catabolite...

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Cells have the ability to regulate the expression of genes. Operon-group of genes co-transcribed by the same promoter sequence Initiation of transcription Within the promoter is the operator ( a set of nucleotides creating a site which is recognized by a regulatory element) [activator or a repressor] Lac operon-inducible (inducer is allolactose) Tryptophane-repressible (repressor is inactive; called an aporepressor “tryp R”) (“co”repressor is tryptophane-amino acid) Lactose-used for carbon source (lac “i” = repressor); allolactose binds to the repressor Positive regulation-enhancement of mRNA production When glucose is present, cells monitor levels of cyclic AMP (molecule monitoring availability of glucose0 When little glucose (cyclic AMP high)
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Unformatted text preview: Cyclic amp works with CAP catabolite activator protein”[regulator] When glucose is low, cyclic amp is low, so the CAP complex has difficulty binding to the promotert and thereby assisting the binding of RNA pol Eukaryotes Chomatin (dna histone complex) chromosome (more structural organization) Histone DNA molecules when wrapper around histone complexes make a nucleosome (ball) Chromosomes observed in DNA replication chromatin remodeling-highly packed nucleosomes modified to stringlike structure to make DNA more accessible to RNA pol Histone acetylation & phosphorylation of histone tails (n terminal)-addition of acetyl or phosphate groups-acetylation of histone tails prevents them from being packed tight together...
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This note was uploaded on 05/20/2010 for the course BIOL 101 taught by Professor Fevzidaldal during the Fall '08 term at UPenn.

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