BSCI 105 Chapter Notes - Chapter 18: Trp Operon, Lac Operon, Lac Repressor
31 Jan 2016
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Chapter 18- regulation of gene expression stages environment. Everyone must change pattern of gene expression in response to. Each cell contains same genome but expresses different genes. Usually regulated during transcription, but still need control at different. Bacteria often respond to environmental change by regulating transcription. Cells don"t want to work so much, so natural selection favors bacteria that express only the genes whose products are needed by cell (save energy) Two levels of metabolic control: cells can adjust activity of enzymes present- which is fast. If too much of something, the cell will repress expression of the genes encoding for the enzyme that creates the product. Occurs in transcription- synthesis of mrna coding for. The cell can translate one mrna into five peparate polypeptides, which make up the different enzymes because of the start and stop codons that signal different polypeptides.
