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Published byMyron Underwood Modified over 9 years ago
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Bacteria Gene Regulation
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Compare/Contrast Prokaryotic and Eukaryotic Protein Synthesis
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How do Prokaryotic Organisms Regulation Gene Expression? Almost ENTIRELY by REGULATION of TRANSCRIPTION The lack of a nucleus makes this very efficient
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What is an operon? An organized cluster of genes that all contribute to a particular metabolic pathway Prokaryotes MOSTLY! (very few have been found in eukaryotes)
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What are the two types of operons? Inducer Operons -> For metabolic pathways normally turned “OFF” (ex: lac operon) Repressible Operons -? For metabolic pathways normally turned “ON” (ex: trp operon)
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The Lac Operon Regulatory Gene (codes for repressor Protein) Promotor Operator LacZ, LacY, LacA Structural genes
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When lactose is absent…
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When lactose is present…
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Repressor Operons…The Trp Operon Regulatory Gene (codes for repressor Protein) Promoter Operator Structural Genes: trpE, trpD, trpC, trpB, and trpA
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When tryptophan is absent:
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When tryptophan is present…
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Why have bacteria that evolved the ability to utilize operons continue to remain in existence?
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Are there some genes in bacteria that are always turned on? YES!!! Ribosomal genes, Respiration Enzymes
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