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35 Cards in this Set
- Front
- Back
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Describe fermentation. There are 4 things that should be noted.
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*final e- acceptor is an organic cmpd
*there is no change in the redox state of the e- donor *low energy yield *many cycles which use many pdts that can be assayed |
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Describe respiration. There are 3 things that should be noted.
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*final e- acceptor is an inorganic cmpd, usually O2
*e- donor changes redox state *hi energy yield |
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What are siderophores? What are they used for?
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They are cmpds used by bacteria to capture Fe(III)
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Under what conditions do obligate anaerobes live? What is an example?
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They cannot live in the presence of O2. E.g. gut flora.
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Under what conditions do aerotolerant anaerobes live?
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They can live in the presence or absence of O2, but grow best in its absence.
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Under what conditions do facultative anaerobes live?
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They are able to live in the presence or absence of O2, but grow best in its presence.
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Under what conditions do obligate aerobes live?
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They can grow only in the presence of O2.
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Under what conditions do microaerophiles live?
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They grow only in the presence of small amounts of O2.
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What is the equation to predict the number of bacteria at time = t?
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Nt = No2^(t/T)
No = initial number of bacteria t = time T = generation time |
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Describe the life cycle of lytic phages.
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*invade baacterium
*begin replication using host machinery *host swells and lyses, releasing a new generation of phages |
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Describe the life cycle of lysogenic phages.
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*invade bacterium
*integrate DNA into host genome *DNA is replicated with host genome and passed to progeny *activated by certain stresses - enter lytic cycle |
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What kind of recombination involves the overlap of a single strand? Of both strands?
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Homologous involves the overlap of a single strand while nonhomologous involves both strands.
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What is homologous recombo based on?
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Sequence similarity.
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A bacterium undergoes homologous recombo with a piece of phage DNA. Describe the genetic makeup of of this bacterium's two daughter cells (after recombo)?
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One daughter will have 2 srands of the parental DNA, and the other will have a double stranded section of the phage insert.
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What is the end result of nonhomologous recombo? How is it done?
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A double-stranded piece of foreign DNA is inserted. This is done enzymatically.
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What is specialized transduction?
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A phage delivers only that DNA which flanked its insertion site on the donor genome.
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What is generalized transduction?
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A phage will transfer any piece of DNA between two bacteria.
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What is transformation?
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Bacterial uptake of naked DNA.
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What is conjugation? How is it usually mediated? What specialized thing is often involved?
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*transfer of DNA between bacteria via direct cell-cell contact
*usually mediated by plasmids *may or may not involve a pilus |
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Name two ways antibiotic resistance is acquired by bacteria.
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1.Chromosomal mutation
2.Picking up R factors from plasmids, phages, or fom another bacteria. |
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What are 3 general strategies for antibiotic resistance?
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1.Modify or inactivate the drug
2.Modify the target of the drug 3.Deny access to the drug |
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What is the S-layer? What is its function?
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An external structure that is a crystalline array of a single protein type. It protects the bacterium.
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What are the 2 forms a polysaccharide layer can take? What does each do?
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1.Capsule: provides protection, slippery surface is anti-phagocytic
2.Slime layer (glycocalyx): allows attachment to solid surfaces |
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What is the structure and function of pili? Where are they anchored?
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Filiments of pilin anchored in the outer membrane that function in attachment.
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What do flagella do? Where are they anchored?
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*function is locomotion
*anchored in the plasma membrane |
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Name 4 things that can serve as antigens. 3 of them have letter codes.
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1.flagella - H Ag
2.LPS - O Ag 3.capsule - K Ag 4.teichoic/teichuronic acids |
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What are the 5 stages of biofilm development?
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1.Adsorption of microbes
2.Irreversible attachment 3.Growth & division 4.EPS and biofilm formation 5.Attachment of other bugs |
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Name 3 ways normal flora provide protection against pathogens.
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1.Physical blocking
2.Synth of inhibitory cmpds 3.Stimulation of host defenses |
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What are 4 mediators of endotoxic shock?
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1.Lipid A/LPS (on G- only)
2.Lipoproteins 3.Peptidoglycan 4.Other sugars |
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What are 4 members of the TLR family and what do they bind?
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1.TLR-4: LPS
2.TLR-2: peptidoglycan 3.TLR-5: flagella 4.TLR-9: bacterial DNA |
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What are Koch's postulates? (3)
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1.Isolate bacteria from sick pt
2.Grow bacteria in pure culture 3.Infect another animal with isolate |
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What are 3 diffiiculties in the use of BT agents?
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1.Hard to produce highly transmissible forms.
2.Some require high inoculum and have no p-p spread 3.Agents with p-p spread are impossible to control |
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T/F:
Most exogenous nosomial pathogens are G+. |
False: most exogenous nosocomial pathogens are G-
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What are 2 aspects that make exogenous nosocomial pathogens difficult to deal with?
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1.Able to withstand harsh conditions
2.Multi-drug resistance |
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What are 4 things that make BT agents dangerous?
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1.Readily available
2.Inexpensive to produce 3.Easy to transport 4.Not easily detectable (5.Incubation time can make it difficult to determine time and place of release) |
