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Micro lab midterm
n/A
60
Biology
Undergraduate 3
03/03/2009

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Cards

Term
What kind of count involves a serial dilution?
Definition
standard plate count
Term
5 environmental factors that affect bacteria growth.
Definition
temperature, osmotic pressure, pH, oxygen availability, medium composition
Term
3 things that medium composition affects
Definition
susceptibility to antibiotics, heat resistance, colony characteristics
Term
What count? Counts all cells, living and dead, uses hemocytometer and miroscope.
Definition
Direct microscopic count
Term
What count method? estimates weight of cells rather than number, involves centrifuging, counts all cells living and dead
Definition
Cell mass determination
Term
Titer
Definition
Number of organisms per milliliter of liquid culture or suspension
Term
What count method? Bacterial sample is added to liquefied warm agar, bacteria are evenly distributed inside the agar. Bacteria grow on the surface and within the agar.
Definition
Pour plate method
Term
Why don't some bacteria survive the pour plate method?
Definition
The agar is too hot - 45C
Term
What count method? Sample is spread on surface of agar --> bacteria are only on the surface.
Definition
spread plate method
Term
What UV wavelengths are effective for radiation? And which is the most effective for radiation?
Definition
240-300 ... 260
Term
What kind of bacteria can survive in the presence of oxygen but won't use it for metabolism?
Definition
Aerotolerant anaerobes
Term
How much O2 is in the air?
Definition
20%
Term
___ is the basal component of rich broth.
Definition
Fluid Thioglycollate medium
Term
3 possible reducing agents in fluid thioglycollate medium
Definition
cysteine, sodium thioglycollate, glutathione
Term
Fluid thioglycollate medium contains __% agar... what is the significance of this?
Definition
0.5% ... not enough to solidify but supports and minimizes oxygen diffusion
Term
Indicator used to detect the presence of Oxygen in fluid thioglycollate medium
Definition
rezaurin
Term
Why is fermentation a valuable tool in the identification of certain species of bacteria?
Definition
It creates a variety of end products
Term
In citrate utilization reactions, what is the purpose of each component?
Simmons citrate agar :: citrate :: ammonium salts :: bromo blue
Definition
Simmons: used to detect the reaction :: citrate: sole source of C :: Ammonium: sole source of N :: bromo blue: changes from green to blue when organism causes alkalinity
Term
A positive citrate utilization test will produce ___.
Definition
NH3
Term
Reduction potential becomes more positive/negative as the electron transport chain continues.
Definition
positive
Term
___ shows gas production by inserting a smaller, upside down tube into a larger test tube with culture.
Definition
Durham tubes
Term
___ is used if it were important that we know the composition of gas
Definition
Smith tube
Term
Respiration or fermentation? presence of external electron acceptors
Definition
respiration
Term
Respiration or fermentation? carbon atoms of organic compounds are completely oxidized.
Definition
Respiration
Term
In respiration, ATP is prodcued through ____.
Definition
Oxidative phosphorylation
Term
More energy is released in respiration or fermentation?
Definition
respiration
Term
Respiration or fermentation? involves the ETC
Definition
respiration
Term
the end products of respiration are __ and __.
Definition
CO2 and H2O
Term
Respiration or fermentation? carbon atoms of organic compounds are only partially oxidized.
Definition
fermentation
Term
in fermentation, ATP is produced through ____.
Definition
substrate level phosphorylation
Term
sugar fermentation broth uses what dye? What color is it at neutral pH? What color is it at acidic pH?
Definition
bromo blue :: green :: yellow
Term
The Indole production test for ____. Indole is the intermediate in this compound's breakdown.
Definition
Tryptophan
Term
The ___ test indicates the presence of the enzyme tryptophonase.
Definition
Indole production
Term
What happens when you add Kovac's reagent to an Indole test?
Definition
If it reacts with Indole, it turns red
Term
What does the methyl red test test for?
Definition
strong acid production from fermentation
Term
The methyl red test turns red at pH ___?
Definition
less than 4.4
Term
The methyl red test has a small/large acid:alcohol ratio?
Definition
large
Term
The methyl red test is used for what kind of bacteria?
Definition
enteric -- intestinal or soil
Term
What medium is used for the methyl red test?
Definition
MR-VP
Term
The methyl red tests for fermentation of ___.
Definition
glucose
Term
The ___ test indicates fermentation of glucose to 2,3-butandiol and ethanol.
Definition
Voges-Proskauer (VP)
Term
The VP test detects the presence of ____.
Definition
Acetoin
Term
The VP test has a small/large acid:alcohol ratio.
Definition
Large
Term
Small/Large amount of gas is produced in the VP test.
Definition
Large
Term
The VP test involves adding ____ reagent and waiting for 20 min. A positive result is indicated by what?
Definition
Barritts A and B -- red or pink color
Term
3 Tests that test for metabolic intermediates or end-products.
Definition
Indole, MR, VP
Term
4 tests that test for the presence of specific enzymes
Definition
Oxidase, Catalase, Urease, Cysteine
Term
The Oxidase test determines if organisms have ____.
Definition
Cyt C oxidase
Term
___ are hemoproteins that transfer electrons to acceptors.
Definition
Cyt C oxidase
Term
The ___ test uses a dye that substitutes for oxygen as an artificial electron acceptor.
Definition
Oxidase
Term
Positive result for oxidase test
Definition
If the dye is reduced, it turns a blue/black color
Term
In the catalase test, Catalase converts ___ to __ and ___.
Definition
hydrogen peroxide to H2O and O2
Term
What types of bacteria usually have catalase?
Definition
facultative aerobes and obligate aerobes
Term
How do you know if a catalase test is positive?
Definition
Bubbles when H2O2 is present
Term
The urease test determines the ability of organisms to?
Definition
hydrolyze urea
Term
___ converts urea to ammonia
Definition
urease
Term
positive result to a urease test
Definition
if urease is present --> turns hot pink due to pH increase
Term
The cysteine desulfurase test tests for?
Definition
H2S production
Term
Medium used for cysteine desulfurase test?
Definition
Klinger's iron agar (KIA slant)
Term
Positive result for the cysteine desulfurase test.
Definition
dark precipitate indicates H2S production :: yellow = positive fermentation
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