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Microbiology Lab Practical 2 (Lab Quizzes)

Terms in this set (59)

Who discovered that infecting an animal with Pseudomonas aeruginosa could help treat infection with Bacillus anthracis?

Robert Koch
Alexander Fleming
Paul Ehrlich
Louis Pasteur
Louis Pasteur
Discovered by Waksman in 1940, the antibiotic streptomycin is produced by a species of:

protozoans
bacteria
viruses
fungi
bacteria
Another term for the Kirby-Bauer antibiotic susceptibility test is the:

disk diffusion method
minimum inhibitory concentration test
hybridization method
immunodiffusion method
disk diffusion method
What type of agar is recommended for performing Kirby-Bauer tests?

Pasteur-Fleming agar
Müller-Hinton agar
Kirby-Bauer agar
Michael-Jackson agar
Müller-Hinton agar
In order to perform a Kirby-Bauer test, a pure culture of the bacteria of interest is swabbed onto a plate, creating a bacterial:

field
lawn
yard
garden
lawn
Arrange the steps in performing a Kirby-Bauer antibiotic susceptibility test from earliest (1) to latest (4):

1) apply antibiotic disks to the plate

2) incubate the plate for 1-2 days

3) measure the zones of inhibition use a metric ruler

4) swab bacteria onto the agar plate
4, 1, 2, 3
True or false: It is very important to sterilize your forceps before using them to position the antibiotic disks onto your agar plate.
false
True or false: In the Kirby-Bauer antibiotic susceptibility test t is very important to thoroughly swab the agar plate so all (or nearly all) of the agar surface is covered by bacteria.
True
Viewing ONLY the results of this Kirby-Bauer test (and not looking up any additional numbers or interpretation), which antibiotic would be the very best choice for treating an infection with this particular bacterial species?
Cannot be assured
Suppose the disk labeled "S" above contains streptomycin, 10 ug, and the zone of inhibition measures 16 mm. Select the proper interpretation:
These bacteria are sensitive to streptomycin.
Which would be the most efficient method to determine whether bacteria within a zone of inhibition (ZOI) have been killed by the antibiotic, or just inhibited from growing?

Use a sterile loop to transfer some bacteria from the ZOI to fresh media, incubate, and check for growth.

Obtain a sample of bacteria from the ZOI and send them to a lab for DNA analysis.

incubate the plate a few more days or weeks to see if bacteria start growing in the ZOI.
Use a sterile loop to transfer some bacteria from the ZOI to fresh media, incubate, and check for growth.
This is not covered in the lab manual but make an educated "guess." In clinical medicine, when treating a potentially serious infection such as bacterial meningitis, which of these factors are usually considered when choosing an antibiotic?

distribution of the antibiotic to specific tissues of the body

all of these are usually considered

potential serious side effects of the antibiotic

antibiotic susceptibility of the infectious bacteria
all of these are usually considered
Transformation
the uptake of naked DNA by a bacterial cell
Conjuation
contact-dependent transfer of DNA via a pilus
Transduction
transfer of bacterial DNA by a bacteriophage
Transposons
"jumping genes" that can move from the bacterial chromosome to plasmids, vice versa
The most likely explanation for why many bacteria naturally produce restriction enzymes is:

as a defense mechanism against bacteriophages

to create plasmids from chromosomal DNA

to cut DNA during bacterial DNA replication

to assist with RNA transcription
as a defense mechanism against bacteriophages
In the laboratory, bacteria that have been treated with CaCl and exposed to heat are able to take up DNA and are called:

confident

competent

arrogant

incompetent
competent
For each correct statements about the pGLO plasmid we used in lab, select "true." For each incorrect statement, select "false."

it contains a gene that codes for the production of an antibiotic
false
For each correct statements about the pGLO plasmid we used in lab, select "true." For each incorrect statement, select "false."

it contains a gene that codes for antibiotic resistance
true
For each correct statements about the pGLO plasmid we used in lab, select "true." For each incorrect statement, select "false."

it contains a gene that codes for green fluorescent protein
true
For each correct statements about the pGLO plasmid we used in lab, select "true." For each incorrect statement, select "false."

it contains a gene that codes for human insulin
false
For each correct statements about the pGLO plasmid we used in lab, select "true." For each incorrect statement, select "false."

it contains a gene that originally came from a jellyfish
true
For each correct statements about the pGLO plasmid we used in lab, select "true." For each incorrect statement, select "false."

it contains the promoter/operator region from the arabinose operon
true
What is the mechanism of action of ampicillin?

inhibits formation of peptide cross-bridges in peptidoglycan

interferes with DNA gyrase

digests the linkages between NAG and NAM molecules in peptidoglycan

breaks apart the beta-lactam ring
inhibits formation of peptide cross-bridges in peptidoglycan
For each correct statement about DNA electrophoresis, select "true." For each incorrect statement select "false."

DNA electrophoresis separates DNA fragments based on size .
true
For each correct statement about DNA electrophoresis, select "true." For each incorrect statement select "false."

DNA fragments have a positive charge, so they are "pulled" towards the negative pole
false
For each correct statement about DNA electrophoresis, select "true." For each incorrect statement select "false."

The size of DNA fragments migrating through a gel can be estimated using a set of DNA fragments called a DNA "escalator.""
false
For each correct statement about DNA electrophoresis, select "true." For each incorrect statement select "false."

DNA restriction enzymes cut DNA at different specific sequences, so cutting DNA with different enzymes will result in different patterns of DNA fragments.
true
Which of these is a lytic bacteriophage of that infects E. coli?

T4

M9

L3

T12
T4
When a lytic bacteriophage infects E. coli, the bacteria will be lysed in about _________ (how long), and each infected bacterial cell will release about ________ virions.

2 minutes; 100

2 minutes; 10

20 minutes; 1000

20 minutes; 100
20 minutes; 100
After obtaining a sample of human sewage, which of these methods would be the most effective at removing large particles as well as some of the larger bacteria and other microbes?
enrichment

incubation

autoclaving

centrifugation
centrifugation
After obtaining a sample of human sewage, which of these methods would be the most commonly used to to increase the number of bacteriophages that infect E. coli?

inoculate some of the sewage onto a special medium that better
supports the growth of this type of phage

treat the sample with anti-viral antibodies

add live E. coli to the sample and incubate

add dead E. coli to the sample and incubate
add live E. coli to the sample and incubate
In the previous question, in microbiology any method that is used to increase the amount of a particular microbe of interest is called:

selection

differentiation

enrichment

discrimination
enrichment
There are (about) five major steps in the replication cycle of a lytic bacteriophage. Match the earliest stage with "1," the next stage with "2," etc., until the last stage (5):

1. adsorption / attachment

2. assembly

3. release

4. penetration

5. synthesis
1, 4, 5, 2, 3
Refer to the Table titled "Comparison of Bacteriophage and Animal Virus Multiplication" at the end of the lecture notes, and note wither each description applies to bacteriophages or animal viruses.

attach to the cell by special tail fibers
bacteriophages
Refer to the Table titled "Comparison of Bacteriophage and Animal Virus Multiplication" at the end of the lecture notes, and note wither each description applies to bacteriophages or animal viruses.

inject their nucleic acid through the cell wall
bacteriophages
Refer to the Table titled "Comparison of Bacteriophage and Animal Virus Multiplication" at the end of the lecture notes, and note wither each description applies to bacteriophages or animal viruses.

some acquire an envelope by budding from the host cell membrane
animal viruses
Suppose you collect blood into the tube shown below and centrifuge. NOTE that EDTA is an anticoagulant, so the blood would be prevented from clotting. What would the liquid on top be called?
plasma
When blood is collected into a tube with an anticoagulant and centrifuged, the "buffy coat" (shown) is made up of mostly:
white blood cells
Which of these should NOT be present in serum?

albumin

clotting factors (e.g., fibrinogen)

antibodies

hormones
clotting factors
What type of white blood cell (leukocyte) is this?

neutrophil

eosinophil

macrophage

monocyte
monocyte
What is indicated by the arrow?

band cell

platelet

reticulocyte

red blood cell
platelet
Match whether each type of WBC is considered a granulocyte or a mononuclear cell:
B cell
mononuclear cell
Match whether each type of WBC is considered a granulocyte or a mononuclear cell:
basophil
granulocyte
Match whether each type of WBC is considered a granulocyte or a mononuclear cell:
natural killer cells
mononuclear cell
Match whether each type of WBC is considered a granulocyte or a mononuclear cell:
band cell
granulocyte
Which is the most likely way to become infected with a bloodborne pathogen?

splash to or contact with broken or non-intact skin

being cut or punctured by a sharp object that is contaminated

splash to or contact with the eyes, nose or mouth
being cut or punctured by a sharp object that is contaminated
Which is the best disinfectant to use during the final stages of cleaning up a spill of blood?

1:10 dilution of household bleach

1:100 dilution of household bleach

undiluted household bleach
1:10 dilution of household bleach
Indicate whether each statement related to B cells and antibodies (Abs) is true or false:

The specific part of an antigen where an an Ab binds is called an epitope.
true
Indicate whether each statement related to B cells and antibodies (Abs) is true or false:

Ab responses are MHC-restricted, meaning they bind only to antigens presented by certain MHC molecules.
false
Indicate whether each statement related to B cells and antibodies (Abs) is true or false:

The different Ab subclasses - IgM, IgG, etc., all bind to different specific antigens
false
Indicate whether each statement related to B cells and antibodies (Abs) is true or false:

A "typical" antibody molecule (such as shown in the lab manual notes) consists of two "heavy" polypeptide chains and two "light" chains.
true
When a B cell undergoes "class switching", it changes which part of the antibody molecules it produces?

constant portion of the light chain

variable portion of the heavy chain

variable portion of the light chain

constant portion of the heavy chain
constant portion of the heavy chain
Match each Ab class with the best description: IgA
the predominant type secreted onto mucosal surfaces
Match each Ab class with the best description: IgE
most is bound to FcE receptors on mast cells
Match each Ab class with the best description: IgG
the most common type in serum, crosses the human placenta
Match each Ab class with the best description: IgM
the first type produced
What is a toxoid?
antibodies produced that neutralize a bacterial exotoxin

vaccine produced by altering a toxin so it is no longer harmful

antibodies produced that neutralize a bacterial endotoxin
vaccine produced by altering a toxin so it is no longer harmful
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