Chapter R-15: Genetics of Bacteria and Bacteriophages and Beginning of Chapter 18: Regulation of Gene Expression in Bacteria

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27 Terms

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bacteria are good experimental organisms because...

-haploid

-single chromosome

-small genome

-short generation times

-easy to maintain

<p>-haploid</p><p>-single chromosome</p><p>-small genome</p><p>-short generation times</p><p>-easy to maintain</p>
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prototroph

-can synthesize all of the building blocks from a carbon source and salts

-a strain can grow on minimal medium (wildtype E.coli is a prototroph)

<p>-can synthesize all of the building blocks from a carbon source and salts</p><p>-a strain can grow on minimal medium (wildtype E.coli is a prototroph)</p>
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auxotroph

-does not grow on minimal medium

-requires nutritional supplements in the media because it can't synthesize it

<p>-does not grow on minimal medium</p><p>-requires nutritional supplements in the media because it can't synthesize it</p>
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genotype designations

a bacterial strain that can't synthesize something will have a minus and a if it can synthesize something it will have a plus

<p>a bacterial strain that can't synthesize something will have a minus and a if it can synthesize something it will have a plus</p>
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conjugation

a process in which there is a unidirectional transfer of genetic information through direct cellular contact between a donor bacterial cell and a recipient bacterial cell

<p>a process in which there is a unidirectional transfer of genetic information through direct cellular contact between a donor bacterial cell and a recipient bacterial cell</p>
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Conjugation Details

-conjugation is from donor to recipient

-donor must have F-factor which is a plasmid that is self-replicating circular DNA that is seperate from the chromosome. it has an origin and contains genes to make f-pilli which allow the donor to attach to the recipient

<p>-conjugation is from donor to recipient</p><p>-donor must have F-factor which is a plasmid that is self-replicating circular DNA that is seperate from the chromosome. it has an origin and contains genes to make f-pilli which allow the donor to attach to the recipient</p>
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transconjugants

recipients that have incorporated a piece of donor DNA into their chromosomes

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transformation

-the unidirectional transfer of extra-

cellular DNA into cells, resulting in a phenotypic change

in the recipient

-incorporates naked DNA from the environment

<p>-the unidirectional transfer of extra-</p><p>cellular DNA into cells, resulting in a phenotypic change</p><p>in the recipient</p><p>-incorporates naked DNA from the environment</p>
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competent

cell that is able to take up DNA from the environment

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transformants

recipients whose genotype + phenotypes are changed by

transformation

<p>recipients whose genotype + phenotypes are changed by</p><p>transformation</p>
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transduction

a process by which bacteriophages (bacterial viruses; phages, for short) transfer genes from one bacterium (the donor) to another (the recipient)

<p>a process by which bacteriophages (bacterial viruses; phages, for short) transfer genes from one bacterium (the donor) to another (the recipient)</p>
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generalized transduction

-the process by which a phage can transfer any gene from a donor to a recipient bacterium

-phage puts pieces of the host cell's DNA into phage particles

-the phages only have donor genes and infect bacteria but do not kill them, recipient's phenotype may be changes

<p>-the process by which a phage can transfer any gene from a donor to a recipient bacterium</p><p>-phage puts pieces of the host cell's DNA into phage particles</p><p>-the phages only have donor genes and infect bacteria but do not kill them, recipient's phenotype may be changes</p>
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bacterialphage

bacterial virus

<p>bacterial virus</p>
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Lederberg and Tatum Experiment

demonstrated recombination and conjugation in E.coli by using a mixture of two auxotrophs, one for Met and Bio and auxotroph thr, leu, and this. they combined to make a prototroph

<p>demonstrated recombination and conjugation in E.coli by using a mixture of two auxotrophs, one for Met and Bio and auxotroph thr, leu, and this. they combined to make a prototroph</p>
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strain

mutant form of an organism that differs in some way from wild-type

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Davis' U-tube Experiment

-2 different strains on opposite sides separated with pores too small for the bacteria to pass through and no prototrophic recombinants were formed

-showed that physical contact was needed for conjugation

<p>-2 different strains on opposite sides separated with pores too small for the bacteria to pass through and no prototrophic recombinants were formed</p><p>-showed that physical contact was needed for conjugation</p>
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donor

must be F+

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recipient

must be F-

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lytic cycle of bacteriophages

knowt flashcard image
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gene expression in bacteria

-it is the process by which information contained in a gene is converted into a function gene product that performs some function of the gene

-not all genes are regulated all the time and regulation of gene expression is critical

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constitutive

-gene that is expressed all the time and product of gene is always needed

-they are always on

-ribosomal proteins, ribosomal RNA, proteins that make up core RNA polymerase

<p>-gene that is expressed all the time and product of gene is always needed</p><p>-they are always on</p><p>-ribosomal proteins, ribosomal RNA, proteins that make up core RNA polymerase</p>
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regulated

-sometimes its expressed, sometimes it's not and product of gene is not always needed

-expression can be turned on and off in response to the cell's needs

<p>-sometimes its expressed, sometimes it's not and product of gene is not always needed</p><p>-expression can be turned on and off in response to the cell's needs</p>
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positive regulation

-regulatory protein triggers transcription

-activator protein

<p>-regulatory protein triggers transcription</p><p>-activator protein</p>
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negative regulation

-regulatory protein shuts down transcription

-repressor protein

<p>-regulatory protein shuts down transcription</p><p>-repressor protein</p>
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transcriptional control

-regulatory mechanisms that operate on the DNA and affect the rate at which transcription initiates

-most efficient but longest for cell to respond

<p>-regulatory mechanisms that operate on the DNA and affect the rate at which transcription initiates</p><p>-most efficient but longest for cell to respond</p>
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post-transcriptional (translational)

-regulatory mechanism that operates on preexisting mRNA and affects mRNA lifespan, which impacts translation

-more rapid than transcriptional control

<p>-regulatory mechanism that operates on preexisting mRNA and affects mRNA lifespan, which impacts translation</p><p>-more rapid than transcriptional control</p>
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post-translational control

-regulatory mechanisms that operate on the protein after synthesis and affect protein activity

-mechanisms that activate and inactivate a protein

-provides the most rapid response and only one step is needed to activate/inactivate an existing protein, but least efficient

<p>-regulatory mechanisms that operate on the protein after synthesis and affect protein activity</p><p>-mechanisms that activate and inactivate a protein</p><p>-provides the most rapid response and only one step is needed to activate/inactivate an existing protein, but least efficient</p>