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