Lab Quiz 2 for MCRO 251 UNC (Labs 6-11)

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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.


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