Lab Quiz 2 for MCRO 251 UNC (Labs 6-11)
The enzyme cytochrome oxidase is produced by oxidase ________ (positive or negative) organisms.
positive
Sabouraud dextrose agar plates are good for
propagating fungi
In an oxidase positive organism, the colonies turn ______. (color?)
purplish
If an organism is catalase positive, _____________ occurs.
rapid and vigorous bubbling
plates good for propagating fungi are ____.
sabouraud dextrose agar
plates good for a large variety of bacteria are _____.
sheep blood agar (SBA)
______________ is used to prevent the spread of the phage so we can count plaques.
soft agar
What medium is used during the bacteriophage titration?
soft agar tubes
An example of a faculative anaerobes are ________.
staphylococci
An example of aerotolerant anaerobes are __________.
streptococci
The artificial electron donor is called
tetramethyl-p-phenylenediamine
Step 2
the phage DNA genome is injected into the bacterium via needle the phage makes
Step 1
the phage attaches to the bacterial cell wall
As phages attach to bacterium,
they inject its phage DNA into the bacterium
Hydrogen peroxide is ________ to the cell.
toxic
What bacteria does the catalase test differentiate?
two groups of Gram-positive cocci: staphylococci and streptococci
aerotolerant anaerobes
use fermentation for ATP but can tolerate oxygen
Step 3
using phage DNA as a template, more phage genomes are made by the bacterial DNA polymerase
The final end product of the cytochrome enzyme system is
water
What may happen due to a fibrin clot?
white blood cells can be walled off from the cocci
What inoculation tool is used for the oxidase test?
wooden applicator stick
Bacteria that are oxidase negative are ________.
Enteric bacteria (members of Enterobacteriaceae)
Bacteria that are oxidase negative are members of the ___________ family.
Enterobacteriaceae
What does the enzyme catalase do?
It breaks down hydrogen peroxide into water and oxygen
What does the enzyme cytochrome oxidase do?
It oxidizes an artificial electron donor.
Bacteria that are oxidase positive are _______.
Neisseria and Pseudonomas species
What bacteria does the oxidase test differentiate?
Neisseria and Pseudonomas species from eneteric bacteria
Step 4
Phage genes are transcribed and translated using bacterial cell machinery to produce more phages
If clumps are visible after mixing, the organism is ______________. (name?)
Staphylococcus aureus
What is the oxidase test?
Tests for the presence of Cytochrome oxidase
What is the catalase test?
Tests for the production of catalase by bacteria
What is the coagulase test?
Tests for the production of coagulase
Which dilution has the appropriate amount of plaques to use for the calculation?
The dilution with double digits
Step 5
The new phages lyse the bacterium, allowing the phages to exit the bacterial cell.This results in bacterial cell death
False positives may occur if ________.
The test is not read quickly
What is a plaque assay used for?
To determine the viral titer (to determine the concentration of phage in the undiluted stock)
A false positive for the oxidase test appears _____. (color)
pink
What tool is used during bacteriophage titration?
pipets
If clumps are visible after mixing, the organism is coagulase ____________(positive or negative)
positive
If the colonies turn purplish, it is an oxidase __________(positive or negative) organism.
positive
Neisseria and Pseudonomas species are oxidase ________. (positive or negative)
positive
Staphylococcus aureus is coagulase __________ (positive or negative)
positive
What is the equation to determine bacteriophage titer?
(number of plaques counted * dilution factor) / (volume of phage plated in ml)
What is the life cycle of a bacteriophage?
1. The phage attaches to the bacterial cell wall 2. The phage DNA genome is injected into the bacterium via needle that the phage makes 3. Using the phage DNA genome as a template, more phage genomes are made by the bacterial DNA polymerase. 4. Phage genes are transcribed and translated using bacterial cell machinery to produce more phages 5. The new phages lyse the bacterium, allowing the phages to exit the bacterial cell. This results in bacterial cell death
The dilution factor is
1/dilution
During aerobic respiration, __ types of enzyme systems are used.
2
What is a plaque assay?
A technique developed for the study of bacteriophages
______ organisms must have catalase to remove hydrogen peroxide.
Aerobic
Tetramethyl-p-phenylenediamine is the _____________.
Artificial electron donor
Why is coagulase associated with virulence?
Because fibrin is deposited onto the cocci and protects it from phagocytosis
How does blood plasma clot?
By converting fibrinogen to fibrin
What does the enzyme coagulase do to blood?
Causes blood plasma to clot
The conversion of fibrinogen to fibrin is caused by ______.
Coagulase
An artificial electron donor is oxidized by _______.
Cytochrome oxidase
Oxidase positive organisms produce __________.
Cytochrome oxidase
What bacteria does the coagulase test differentiate?
Differentiates pathogenic Staphylococcus aureus from non-pathogenic staphylococci
The catalase test differentiates what Gram-positive cocci?
Differentiates staphylococci from streptococci
If an organism is catalase negative, ____________.
a few bubbles are released
Hydrogen peroxide is formed __________. (aerobically or anaerobically)
aerobically
Streptococci are _______________ (oxygen type?)
aerotolerant anaerobes
Bacteriophages infect
bacteria
Pre-Step 1
bacteria is grown on plate with phage
The walling off of white blood cells from the cocci results in ________.
boils and pimples
Faculative anaerobes
can live with or without oxygen
Hydrogen peroxide is broken down into water and oxygen by _________.
catalase
Steptococci lack ___________. (what enzyme)
catalase
What removes hydrogen peroxide from the cell?
catalase
The loop is used for which tests?
catalase and coagulase
If an organism is coagulase positive, the mixture will be ______.
clumpy
The coagulase test asses the bacteria's ability to __________.
coagulate plasma (clump)
We are starting with a __________ phage stock and are __________ it to count the plaques
concentrated; diluting
What does coagulase do?
converts fibrinogen to fibrin
The enzyme systems used during aerobic respiration use ______________ and _______________.
cytochromes and flavoprotein oxidases
The bubbling from a catalase positive organism after adding hydrogen peroxide is ______.
oxygen released as catalase breaks down the hydrogen peroxide
A catalase test should not be performed on ______________.
dilute broth culture
A coagulase test should not be performed on ______________.
dilute broth culture
An oxidase test should not be performed on ______________.
dilute broth culture
The enzyme systems are involved in _________.
electron transport
Staphylococci are ____________. (oxygen type?)
faculative anaerobes
If a result for the oxidase test appears pink, it may be a _________.
false positive
An oxidase test must be read within 5-10 seconds or it may result in a ________.
false positive.
An oxidase test should be performed on ______________.
fresh growth from solid media
sheep blood agar plates are good for
growth of a large variety of bacteria
If an organism is coagulase negative, the mixture will be ________.
homogenous and white/milky
The final end product of the flavoprotein oxidase enzyme system is
hydrogen peroxide
What product of aerobic respiration is toxic to the cell?
hydrogen peroxide
the phage particles released from the host cell after lysis can then __________.
infect neighboring host cells
What inoculation tool is used for the catalase test?
loop
What inoculation tool is used for the coagulase test?
loop
More phage means what in terms of bacterial death?
more bacterial death
Enteric bacteria are oxidase _______. (positive or negative)
negative
If the colonies don't change color, it is an oxidase _________ (positive or negative) organism.
negative
If the mixture is homogenous and white/milky, the organism is coagulase __________ (positive or negative)
negative
Members of the family Enterobacteriaceae are oxidase ________. (positive or negative)
negative
In an oxidase negative organism, the colonies turn _____. (color?)
no color
what was used during the microbial floral lab? (3)
normal hand soap antibacterial soap alcohol sanitizer
A wooden applicator stick is used for the ___________ test.
oxidase
The presence of cytochrome oxidase is tested by the _________ test.
oxidase
The purpose of the cytochrome oxidase enzyme is to _____________.
oxidize an artificial electron donor
Hydrogen peroxide is formed in aerobically because
oxygen is there to accept the electrons.
