BIO230H1 Lecture Notes - Lecture 2: Lac Operon, Lac Repressor, Trp Operon
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BIO230H1 Full Course Notes
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Lecture 2 - prokaryotic transcriptional regulation: genetic switches, trp operon, lac operon. Can also be associated with disease state eg. cancer. Eg. extreme case some genes are only expressed in one particular cell type - hemoglobin. Responses to extracellular stimuli (both multicellular and unicellular organisms) Recall that dna is transcribed into rna by the enzyme rna polymerase. Dna rna hybrid, ribonucleoside triphosphates are added onto the 3" end. Sigma factor find the promoter, which indicated the transcription start site. Genes can be transcribed at different efficiencies. Regulated similarly in both prokaryotes and eukaryotes. Gene expression in both prokaryotes and eukaryotes is regulated by: gene regulatory proteins (transcription factors ) Which bind specifically to: regulatory regions of dna (cis-elements) Gene regulatory proteins were discovered using bacterial genetics. Anything found to be true of e. coli must also be true of elephants. Double every 20 min, in the 20 min period they will try to find food.
