Lab Quiz 4
Biological Sciences 101 with Daad Saffarini at University of Wisconsin - Milwaukee
About this deck
By: Sarah Norton
Textbook:
Microbiology: An Introduction, Books a la Carte Edition (10th Edition)
Created: 2010-05-03
Size: 51 flashcards
Views: 16
Textbook:
Microbiology: An Introduction, Books a la Carte Edition (10th Edition)Created: 2010-05-03
Size: 51 flashcards
Views: 16
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What is the objective of quantitative plating?
- To perform a plate count
- determined the number of microbes in a sample of raw milk
- witness the effectiveness of pasteurization
Pasteurization
Method of decreasing the number of bacteria in a sample
DOES NOT sterilize it
Kills all pathogens that commonly found in milk
DOES NOT sterilize it
Kills all pathogens that commonly found in milk
The two types of pasteurization?
LTH-low temp.- long time
HTST-high temp.-short time (used commercially)
HTST-high temp.-short time (used commercially)
What are the acceptable limits for milk?
Raw-105 /ml (100,000 cells/ml)
Pasteurized- 2 X 104
Pasteurized- 2 X 104
What do the number of colonies represent in the pour plate method
The number of colony forming units (cells) per ml of original sample
What is the amount of colonies to look for in a serial dilution?
30-300
Dilution Factor
volume (ml) of a sample/ total volume (ml)
# bacteria/ml sample
number of colonies/dilution factor (of bottle) X sample volume (vol added to plate)
OR
number of colonies/final dilution factor (on plate)
OR
number of colonies/final dilution factor (on plate)
Nitrate reduction
ability of an organism to reduce nitrate to nitrite
measures the reduction of nitrite to more reduced products i.e. nitrogen gas or ammonium
measures the reduction of nitrite to more reduced products i.e. nitrogen gas or ammonium
under anaerobic conditions nitrate and nitrite serve as terminal electron acceptors....describes what test?
nitrate reduction
What is catalase?
an enzyme used by bacteria to break down toxic compounds like hydrogen peroxide that may be produced by aerobic respiration
What is the result in a positive catalase test?
bubbling
Aerobic and facultative bacteria can produce cytochrome oxidase to be used in aerobic respiration is describing what test?
Oxidase test
What does cytochrome oxidase in the srespiratory chain of bacteria
oxidize what to pass electrons to O2
Cytochrome C, reduces to H2O
What is a positive result for the oxidase test?
turning dark purple within 3o seconds after adding the oxidase reagent
Anaerobes
any organism
that does not require oxygen for growth
Microaerophiles
organisms
are a specific type of microorganism
(especially bacteria) that requires oxygen to
survive, but requires environments containing lower levels of oxygen
than are present in the atmosphere
Facultative Aerobes
one that can live in the presence of oxygen.
Facultative Anaerobes /aerobes
n organism, such as a bacterium, that can live in the absence as well as
in the presence of atmospheric oxygen.
Aerotoloerant anaerobes
do not utilize oxygen, and is not affected by it.
What is a positive result for nitrate reduction?
gas in durham tube
Red color after adding sulfanilic acid and alpha-naphthol
Red color after adding Zinc
Red color after adding sulfanilic acid and alpha-naphthol
Red color after adding Zinc
What are the common products of carbohydrate breakdown by microbes
organic acids
i.e. acetic and lactic
and gasse such as carbon dioxide and hydrogen
i.e. acetic and lactic
and gasse such as carbon dioxide and hydrogen
What indicator is used to detect the formation of acids
phenol red (red at pH 8.2)
testing for fermentation of various carbohydrates and the nature of fermentation end products is called?
Glucose Iron Agar testing
Glucaose Iron Agar testing uses?
Glucose fermentation
H2S production
O2 requirement
H2S production
O2 requirement
What are the indications of O2 requirement?
Anaerobic-growth inside media
Aerobic- growth on surface of slant
Aerobic- growth on surface of slant
What is a positive result for H2S production?
Black iron sulfide precipitate
(H2S reacts with Fe=black if +)
(H2S reacts with Fe=black if +)
What is a positive result for the fermentation of lactose?
Gas in Durham tube
What does the gelatin hydrolysis test look for?
detects extracellular proteases that can break down proteins
What is a positive result for gelatin hydrolysis
remains liquid after ice bath
what test needed to be incubated for1 week?
Gelatin hydrolysis
What does the starch hydrolysis test look for?
detects the exoenzyme amylase that can break down starch
What is a positive result for starch hydrolysis?
the production of amylase will result in a clear zone around growth= positive amylase production OR blue/black color formation
What does Urease test for?
the enzyme urease that hydrolyzes urea to produce ammonia and CO2.
* ammonia will increase the pH, which will be detected by the phenol red indicator in the media*
* ammonia will increase the pH, which will be detected by the phenol red indicator in the media*
What is a positive result for the urease test?
If the indicator phenol red turns hot pink in broth
What does coagulase production test for?
the exoenzyme coagulase taht coagulates plasma.
What is coagulase
A virulence factor of the pathogenic bacterium Staphylococcus aureus
What was our bacteria inoculated in for the coagulase test?
rabbit plasma
What is a positive result for the coagulase test?
Rabbit plasma solidifies= production of coagulase
What do we look for in the DNase assay test?
the exoenzyme DNase that hydrolyzes DNA
*DNA agar contains mthyl green, which binds to polymerized DNA in the media. When DNA is hydrolyzed a clearing of dye occurs*
*DNA agar contains mthyl green, which binds to polymerized DNA in the media. When DNA is hydrolyzed a clearing of dye occurs*
What is a positive result for the DNase assay test?
A clearing of the green color around growth= DNase production
What is the purpose of the throat culture?
To identify microbes through hemolytic reactions in blood agar, gram stain, and biochemical tests
Normal Flora
microbiota- not typically diseasing causeing
commonly found in and on healthy individuals
commonly found in and on healthy individuals
What is normal flora found?
in or on skin, eyes, nose, mouth, upper throat, lower urethra, vagina, and lower intestine
*all body surfaces exposed to external enviroment*
*all body surfaces exposed to external enviroment*
What can normal flora produce in the large intestine?
Vitamin K
How does blood agar identify pathogens?
It is enriched with red blood corpuscles
*various reactions*
*various reactions*
Alpha reaction
appearance of a greenish tint in areas around the colonies
*breakdown of RBC's, green= production of hydrogen peroxide*
*breakdown of RBC's, green= production of hydrogen peroxide*
Beta reaction
Clear zone of varying diameter around colony
*RBC's have fully disintegrated and the red color has disappeared*
*RBC's have fully disintegrated and the red color has disappeared*
What is a beta reaction called?
Hyeolysis
*hemolysins released by bacterial cells*
*hemolysins released by bacterial cells*
Gamma reaction
No noticeable effect of bacterial cells
*no breakdown of RBC's*
*no breakdown of RBC's*
About this deck
By: Sarah Norton
Textbook: Microbiology: An Introduction, Books a la Carte Edition (10th Edition)
Created: 2010-05-03
Size: 51 flashcards
Views: 16
Textbook:
Microbiology: An Introduction, Books a la Carte Edition (10th Edition)Created: 2010-05-03
Size: 51 flashcards
Views: 16
About StudyBlue
STUDYBLUE makes things that make you better at school.
Things like online flashcards with photos and audio.
Things like personalized quizzes and friendly reminders about when (and what) to study next.
Think of it as a digital backpack™: access to all of your study materials online and on your phone.
STUDYBLUE exists to make studying efficient and effective for every student, for free. Join us.
“I have used this website for three exams, and I see a huge difference in my test results.”
Naj
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