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Unformatted text preview: Chapter 18: The Genetics or Viruses and Bacteria Operons: The Basic Concept - A key advantage of grouping genes of related function into one transcription unit is that a single on-off switch can control the whole cluster of functionally related genes- Operator: A sequence of nucleotides near the start of an operon to which an active repressor can attach o The binding of the repressor prevents RNA polymerase from attaching to the promoter and transcribing the genes of the operon o Positioned within the promoter or between the promoter and the enzyme encoding genes, the operator controls the access of RNA polymerase to the genes - Operon: A unit of genetic function common in bacteria and phages, consisting of coordinately regulated clusters of genes related functions o Can be switched off by a protein called the trp repressor The repressor binds to the operator and blocks attachment of RNA polymerase to the promoter, preventing transcription of the genes Repressor protein is specific o It recognizes and binds only to the operator of a particular operon...
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