genetics of bacteria
DESCRIPTION
Genetics of Bacteria. Bacterial genome =. Genetics of Bacteria. Bacterial genome = One circular DNA molecule E. coli chromosome has 100 times more DNA than in a typical virus, but much less than a eukaryotic cell. Packed into nucleoid region of cell Plasmid =. Genetics of Bacteria. - PowerPoint PPT PresentationTRANSCRIPT
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Genetics of Bacteria
• Bacterial genome =
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Genetics of Bacteria
• Bacterial genome = One circular DNA molecule
• E. coli chromosome has 100 times more DNA than in a typical virus, but much less than a eukaryotic cell.
• Packed into nucleoid region of cell
• Plasmid =
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Genetics of Bacteria
• Bacterial genome = One circular DNA molecule
• E. coli chromosome has 100 times more Dna than in a typical virus, but much less than a eukaryotic cell.
• Packed into nucleoid region of cell• Plasmid = small circular extra piece of
DNA
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Bacterial Genetic Recombination
• What is the main source of genetic recombination in bacteria?
• Mutations
• What are the other sources of recombination?
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Transformation
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Transduction
What is the vector of
transduction?
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Conjugation
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Plasmids• What is a plasmid?
• Small circular, self replicating piece of bacterial DNA
• Plasmid genes are advantageous to the bacteria that has them
• Plasmids that confer resistance to antibiotics are called R plasmids
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Regulation of Gene expression in prokaryotes (operons)Why is it important that regulation of protein production occur in an organism?
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Repressible operons• Repressible operons have structural genes
that code for the production of the substrate (anabolic process).
• The repressor protein is produced in an inactive form, leaving the operator open
• In the presence of the substrate, the substrate will allosterically bind to the repressor protein (is a co-repressor) and activate the repressor protein causing it to bind to the operator
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Inducible operons• Inducible operons have structural genes
that produce enzymes that break down a substrate (catabolic process).
• The repressor is translated into its active configuration and will bind to the operator in the absence of the substrate.
• If the substrate is present, it binds to the repressor protein and de-activates it, thereby opening up the operator.
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In the lac operon, cAMP acts as a volume control…
What would happen if:
•High glucose, high lactose?
•Low glucose, high lactose?
•High glucose, low lactose?
•Low glucose, low lactose?
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Transformation Lab
• Each plate….– What amount of
growth do you expect?
– What is the purpose of the plate (hint: what would be indicated if amount of growth did NOT match expected?)?
• LB plate (-pGLO)• LB/amp plate (-pGLO)• LB/amp plate (+pGLO)• LB/amp/ara plate
(+pGLO)
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Ampicillin resistance gene
Gene for regulatory protein for arabinose operon
Modified arabinose operon – genes for enzymes replaced with pGLO gene (codes for glowing fluorescent protein = GFP)