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11 Cards in this Set
- Front
- Back
three different "bacterial genome" components
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• Bacterial chromosome - large DNA molecule, usually circular, contains all genes necessary for growth under normal conditions.
• Plasmids - small DNA molecules, usually circular, replicate independently from chromosome, encode genes for a variety of nonessential genes-- for example, those that make proteins that provide toxicity or antibiotic resistance. • Bacterial viruses - a bacteriophage chromosome incorporated into the bacterial chromosome; this can influence the phenotype of the bacterial cell (see below, "lysogenic conversion"). Example: diphtheria bacteria is only toxic if it stably acquires a particular viral gene. |
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• Bacterial chromosome -
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large DNA molecule, usually circular, contains all genes necessary for growth under normal conditions.
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• Plasmids -
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small DNA molecules, usually circular, replicate independently from chromosome, encode genes for a variety of nonessential genes-- for example, those that make proteins that provide toxicity or antibiotic resistance.
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• Bacterial viruses
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- a bacteriophage chromosome incorporated into the bacterial chromosome; this can influence the phenotype of the bacterial cell (see below, "lysogenic conversion").
Example: diphtheria bacteria is only toxic if it stably acquires a particular viral gene. |
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• Gene acquisition methods:
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Transposable elements:
Bacteriophage conversion Acquisition of plasmids Acquisition of "pathogenicity islands" |
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prophage
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viral DNA in the host chromosome
prophage can be induced to enter lytic state -->viral replication |
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temperate phages
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dont kill host cells.
elicit lytic response --> phage multiplication and hoset cell lysis (lysogenic response) |
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what does the repressor protein do in the lysogenic state
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the prophage encoded respressor protein maintains the lysogenic state and blocks expression of the phage genes that are required for viral DNA replication and lytic development
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lysogenic cycle
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integration of bacteriophage DNA into host bacteriums genome.
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lytic cycle
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main method of viral replication. results in destruction of infected cell
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conjugative transposon
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mobile elements for conjucation between pairs of cells
transferred DNA is the conjugative transposon itself. |