Chapter_18_The_Genetics_of_Viruses_and_Bacteria - Chapter...

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Bacterial Production of Enzymes Regulation of gene expression and enzyme activity in bacteria are regulated by a complex system of operons and repressors that indicate which genes should be transcribed. Operon : the stretch of DNA that contains the operator, promoter, and genes the two control. Repressor : the protein that switches off the operon. Repressible Operon (i.e. tryp operon):when the corepressor molecule, ike tryptophan, is present, the operon is switched off. Inductive Operon (i.e. lac operon): when the inducer molecule, like lactose, is present, the operon is switched on. Chapter 18 - Microbial Models: The Genetics of Bacteria Important Genetic Elements of Bacteria (a) Plasmids : small, self-replicating DNA molecules, small number of genes, some can undergo reversible incorporation into the cell. (b) Episomes : genetic elements that can replicate either as plasmids or as part of a chromosome; temperate viruses can qualify as episomes. (c) F Plasmid : has about 25 genes, is needed for the production of sex pili which aids in conjugation ; the F Plasmid is inheritable. d)
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This note was uploaded on 04/01/2012 for the course BIO 141 taught by Professor Dr.cafferty during the Spring '11 term at Emory.

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Chapter_18_The_Genetics_of_Viruses_and_Bacteria - Chapter...

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