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Exam 2
Chapters 5,7,8,9 and 10
58
Microbiology
Undergraduate 3
10/21/2012

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Term
Psychrophiles
Definition
0-20C
Term
Mesophile
Definition
15-45C
Term
Thermophile
Definition
40-80C
Term
Hyperthermophile
Definition
80-121C
Term
Heat-shock response
Definition
stabilizes proteins and membranes in response to high heat.
Term
What are the physical agents that impede bacterial growth?
Definition
Pasteurization, freezing, irradiation, and autoclave.
Term
What is the D-value, and what does it test?
Definition
The D-value tests the efficacy of a lethal agent, refers to the length of the time it takes for the agent to kill 90% of the population.
Term
What pH do acidophiles live in?
Definition
0-5
Term
What do halophiles require?
Definition
High sodium.
Term
Where do Barophiles live?
Definition
High pressure environments
Term
Where do psychrophiles live?
Definition
High pressure environments
Term
Obligate Aerobe
Definition
Requires 02
Term
Obligate Anaerobe
Definition
Requires CO2
Term
Faculative Anaerobe
Definition
Can grow in O2 and CO2, prefers O2.
Term
Microarophile
Definition
Needs small amounts of CO2, less than 21%
Term
Aerotolerant
Definition
Uniformed growth in O2
Term
How do aerobes functions with O2?
Definition
They use peroxidases, super peroxidases, and catalases to break bad things like peroxide.
Term
Do anaerobes have peroxidases?
Definition
No.
Term
What is an autoclave?
Definition
Steam bath that heats bacteria for 121C for 15-20 minutes.
Term
What does heat-labile mean?
Definition
Susceptible to alteration from heat. (proteins are heat-labile).
Term
What is the Phenol Coefficient test, and what is it for?
Definition
It is used to compare disinfectants to phenol by exposing the target to both for 10 minutes.
Term
Facts about plasmids?
Definition
1) Confer bacterial resistance.
2) Multiple plasmids per cell.
3) The can be transmitted via horizontal gene transfer.
4) They are naked DNA.
5) They are only found in bacteria/archae.
6) They are between 2-25kb
Term
How are plasmids replicated?
Definition
Rolling circle replication, which starts at a nick.
Term
What is a high copy, and low copy number for the number of plasmids in a cell?
Definition
more than 50, and 1-2.
Term
What is the central dogma of biology?
Definition
DNA to RNA via transcription.
RNA to protein via translation.
Term
What is mRNA?
Definition
Something that is translated into a protein.
Term
What is a holoenzyme?
Definition
A protein (enzyme) + sigma factor (whcih is located at -10 and -35 bp upstream from the transcription storage site).
Term
What is the sigma factor for, and when does it fall off?
Definition
The sigma factor is for transcription initiation. It falls off during RNA synthesis.
Term
What are the names of chaperonins?
Definition
GROEL, GROES, and DNAK.
Term
What does tRNA do?
Definition
Makes a molecule of RNA from DNA template.
Term
What is Rho dependent termination?
Definition
It involves the Rho factor that moves along the DNA strand and ends transcription.
Term
What is Rho independent termination?
Definition
Transcription that ends when a stop sequence is reached.
Term
What do prokaryotic ribosomes consist of?
Definition
tRNA, RNA, and mRNA (as well as proteins).
Term
30s, 50s, and 70s?
Definition
Prokaryotic
Term
40s, 60s, and 80s?
Definition
Eukaryotic
Term
What can prokaryotes do that eukaryotes cannot (in relation to ribosomes)?
Definition
They can have may ribosomes work simultaneously.
Term
Which cycles are part of the generalized transduction cycles?
Definition
The lytic and lysogenic cycle.
Term
What is does specialized transduction cycle effect?
Definition
Transfer of closely linked genes
Term
What is transformation?
Definition
gene transfer that takes up naked DNA fro the environment.
Term
What is natural transformation and who does it?
Definition
Gram positive do it, and its the natural ability to perform transformation.
Term
What is artificial transformation and who does it?
Definition
Gram negative do it, and its the assisted ability to perform transformation.
Term
What does RecA do?
Definition
scans DNA for homology
Term
What does RecBCD do?
Definition
It unwinds DNA.
Term
What does RuvAVB do?
Definition
Aids in single stranded cross-over pairing.
Term
What are sign of horizontal gene transfer?
Definition
Different genomes between two different members of the species. A different G-C base ratio from flanking chromosomal DNA.
Term
How does replicative tranposition differ from nonreplicative transposition?
Definition
Replicative (copy and paste)
Nonreplicative (cut and paste)
Term
How is cell function regulated?
Definition
Via extracellular signals and biochemical pathways.
Term
Where can an enzyme be most rapidly changes?
Definition
Post translation level.
Term
What does an inducer cause?
Definition
An inducer causes gene expression by binding a repressor protein (inducer starts gene expression).
Term
When is the lac operon maximally transcribed?
Definition
The lac operon is maximally transcribed when lactose is present, but not glucose (because if glucose is present, then you don't need the lactose)
Term
What is a repressor?
Definition
Something that turns off an operon.
Term
What is the mechanism by which the repressor controls the operon?
Definition
Induction.
Term
What is catabolite repression?
Definition
The the product thats usually unavailable represses the operon (glucose is the catabolite responsible for lactose operon repression).
Term
How is the tryptophan operon regulated?
Definition
Its regulated by both repressor, and attenuation (down regulation).
Term
What is attenuation control?
Definition
Stops transcription.
Term
What can small regulatory RNA do?
Definition
Compliment base pairs with mRNA.
Term
What is phase variation?
Definition
An alternative DNA sequence that can code for a bacteria's cell surface structure, such as LPS, PLE, and flagella. This processes involves DNA rearrangement.
Term
When does a stringent response occur?
Definition
When energy stores are low to decrease rRNA transcription.
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