Lab 3, Chapter 11
To study growth characteristics, pathogenicity, metabolism, antibiotic susceptibility or othe
characteristics, requires:
A. A growth medium
B. Agar
C. Broth
D. Pure Culture
A Pure culture contains:
A. Bacteria
B. Virus
C. isolated microbes
D. A single type of microbe
Because bacteria are too small to separate directly without sophisticated
micromanipulation equipment,
of separation are used.
A. Scientific Methods
B. Sterile Methods
C. Microbiology Methods
D. Indirect Methods
In the 1870's
attempted to obtain pure cultures by performing serial
dilutions until each of the containers theoretically contained one bacterium.
A. Joseph Lister
B. Paul Ehrlich
C. Ronald Ross
D. Robert Koch
In 1880
A. Joseph Lister
B. Paul Ehrlich
C. Ronald Ross
D. Robert Koch
prepared solid media
Currently, three dilution methods are commonly used for isolating bacteria:
A. Streak Plate, Spread Plate, Pour Plate
B. Hot Plate, Cold Plate. Warm Plate
C. Red Plate, Blue Plate, Green Plate
D. Acid Plate, Base Plate, Dilute Plate
The
and
number of bacteria in a sample.
A. Streak Plate and Spread Plate
B. Streak Plate a Pour Plate
C. Spread Plate and Pour Plate
are quantitative techniques to determine the
1
The
technique, a loop is used to streak the mixed sample many
times over the surface of a solid culture medium in a Petri dish.
A. Streak Plate
B. Spread Plate
C. Pour Plate
In the
technique, a small amount of a previously diluted specimen is
spread over the surface of a solid medium using a spreading rod.
A. Streak Plate
B. Spread Plate
C. Pour Plate
In the
technique, a small amount of diluted sample is mixed with
melted agar and poured into empty, sterile Petri dishes.
A. Streak Plate
B. Spread Plate
C. Pour Plate
When reporting results for the streak plate method (colony descriptions), which of the following
IS NOT reported?
a.
b.
c.
d.
e.
f.
Diameter
Appearance
Margin
Elevation
Color
pH
Which of the following is TRUE in regards to inoculating a Petri plate?
a. Lift one edge of the corner while the plate rests on the table
b. Lift the entire lid while the plate rests on the table
c. Take the lid off and place it face down on the table, as well as the plate
For the pour plate technique, what happens to the bacteria prior to pouring them into Petri
dishes?
a. We expose them to flame prior to placing them in the incubator
b. We run a series of tests to determine their pH
c. The bacteria are diluted through a series of tubes containing 19 ml of melted
nutrient agar
In regards to Ch.11 “Isolation of Bacteria by Dilution Techniques,” which of the following is
NOT an objective?
a. Isolate bacteria by using the streak plate and pour plate techniques
b. Use various staining techniques in order to isolate bacteria
c. Prepare and maintain a pure culture
2
Which of the following correctly depicts the streak plate technique for pure culture isolation of
bacteria, as depicted in our lab manual?
A
B
C
3
Which of the following depicts the CORRECT way to mix the inoculum in a tube?
A
B
C
4
What is contamination?
a. The presence of unwanted microorganisms
b. The absence of unwanted microorganisms
c. Using a mixed culture to reach a pure culture
Which of the following is NOT one of the most commonly used dilution methods for isolating
bacteria?
a. Streak plate method
b. Spread plate
c. Pour plate
d. A complex medium consisting of peptones
Which of the following is the MOST COMMON isolation technique used today?
a. Streak plate
b. Pour plate
c. Spread plate
Chapter 12
True/False
One of the major limitations of dilution techniques used to isolate bacteria is that organisms
present in limited amounts may be diluted out on plates filled with dominant bacteria. True
If bacterium B is heat-resistant, the specimen could be heated after isolation. False
Dyes such as phenol red, eosin, or methylene blue are sometimes included in differential media.
True
What methods are used to isolate particular organisms?
A. Selective media
B. Enrichment media
C. Differential media
D. All of the above
E. (A and C)
F. None of the above
What is selective media?
A. Contain various nutrients that allow the investigator to distinguish one bacterium from
another by how they metabolize or change the media with a waste product
B. Media that contain nutrients that enhance growth of desired bacteria.
C. Contain chemicals that prevent the growth of unwanted bacteria without inhibiting
the growth of the desired organism.
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What is enrichment media?
A. Contain chemicals that prevent the growth of unwanted bacteria without inhibiting the
growth of the desired organism.
B. Media that contain nutrients that enhance growth of desired bacteria.
C. Contain various nutrients that allow the investigator to distinguish one bacterium from
another by how they metabolize or change the media with a waste product
What is differential media?
A. Contain various nutrients that allow the investigator to distinguish one bacterium
from another by how they metabolize or change the media with a waste product.
B. Media that contain nutrients that enhance growth of desired bacteria.
C. Contain chemicals that prevent the growth of unwanted bacteria without inhibiting the
growth of the desired organism.
Why is special media testing performed?
A. It helps isolate organisms found in the minority
B. Various enrichment and selective culturing methods are available that enhance the growth of
certain organisms.
C. Various enrichment and selective culturing methods are available that inhibit the growth of
certain organisms.
D. All of the above
Selective media contains chemicals that prevent the growth of unwanted bacteria without
inhibiting the growth of the desired organism.
True
Fale
Enrichment media contains chemicals that inhibit the growth of specific desired bacteria.
True
False
Enrichment media is typically
A. Solid and bacteria in addition to the desired one one will grow.
B. Solid and no bacteria other than the desired one will grow.
C. Liquid and bacteria in addition to the desired one will grow.
D. Liquid and no bacteria other than the desired one will grown.
With special media testing, how does one incubate the plate?
A. Inverted at 0 degrees Celcius
B. Inverted at 35 degrees Celcius
C. Right side up at 0 degrees Celcius
D. Right side up at 35 degrees Celcius
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Using differential media, dyes such as phenol red, eosin, or methylene blue are included to
produce a color change in the medium or colonies. What part of the bacteria reacts to this?
A. Products of bacterial metabolism
B. Bacterial cell walls
C. Products of bacteria organelles
D. Proteins in the bacteria
Which techniques are used in special media testing?
A. Streak plate procedure
B. Gram staining
C. Aseptic techniques
D. All of the above
Chapter 22
Extreme ____________ is widely used to control the growth of microbes.
A. temperature
B. moisture
C. light
D. all of the above
Generally, if _____ is applied, microbes are killed; if _____ temperatures are used, microbial
growth is inhibited.
A. cold, hot
B. heat, cold
C. moisture, extreme
D. both A & C
Psychrophilic refers to optimal growth ranges about ____________.
A. 0 degrees celcius to 20 degrees celcius
B. 20 degrees celcius to 30 degrees celcius
C. 25 degrees celcius to 40 degrees celcius
D. 45 degrees celcius to 65 degrees celcius
E. about 80 degrees celcius or higher
Psychrotrophic refers to optimal growth ranges about ____________.
A. 0 degrees celcius to 20 degrees celcius
B. 20 degrees celcius to 30 degrees celcius
C. 25 degrees celcius to 40 degrees celcius
D. 45 degrees celcius to 65 degrees celcius
E. about 80 degrees celcius or higher
Mesophilic refers to optimal growth ranges about ____________.
A. 0 degrees celcius to 20 degrees celcius
B. 20 degrees celcius to 30 degrees celcius
C. 25 degrees celcius to 40 degrees celcius
D. 45 degrees celcius to 65 degrees celcius
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E. about 80 degrees celcius or higher
Thermophilic refers to optimal growth ranges about ____________.
A. 0 degrees celcius to 20 degrees celcius
B. 20 degrees celcius to 30 degrees celcius
C. 25 degrees celcius to 40 degrees celcius
D. 45 degrees celcius to 65 degrees celcius
E. about 80 degrees celcius or higher
Hyperthermophilic refers to optimal growth ranges about ____________.
A. 0 degrees celcius to 20 degrees celcius
B. 20 degrees celcius to 30 degrees celcius
C. 25 degrees celcius to 40 degrees celcius
D. 45 degrees celcius to 65 degrees celcius
E. about 80 degrees celcius or higher
Heat such as that in hot-air ovens or incineration are what type of heating?
A. Moist
B. Dry
C. Extreme
D. None of the above
Heat methods such as pasteurization, boiling, and autoclaving are what type of heating?
A. Moist
B. Dry
C. Extreme
D. None of the above
The most effective method of moist heat sterilization that involves steam under pressure is
known as __________.
A. Boiling
B. Autoclaving
C. Incineration
D. Baking
Match the rate of growth to the correct temperature:
A) Hyperthermophilic
B) Psychrotropic
C) Thermophilic
D) Psychrophilic
E) Mesophilic
Temperature in Degrees (in Celsius)
0-20 (D)
20-30 (B)
25-40 (E)
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45-65 (C)
80 or higher (A)
Overall, bacteria are more ______ resistant that most other forms of life.
A) Heat
B) Cold
Heat sensitivity of organism can be affected by what?
A) Container size and cell density
B) Container size, cell density, and moisture content
C) Container size, cell density, moisture content, and pH
D) Container size, cell density, moisture content, pH, and medium composition
Dry heat denatures enzymes, dehydrates microbes, and kills by oxidation effects.
A) True
B) False
Moist heat methods include which of the following:
A) Pasteurization
B) Boiling
C) Autoclaving
D) All of the above
A psychrophilic optimal growth range is ________?
A. 45° C - 65° C
B. 20° C - 30° C. 25° C - 40° C
D. 0° C - 20° C
A thermophilic growth range is between 45° C - 65° C.
True False
Bacteria is NOT more heat resistant than most others forms of life.
True False
Pasteurization, boiling and autoclaving are all examples of _________
A. Dry Heat
B. Moist Heat C. Thermophilic
D. Procedure Heat
Hot air ovens and incineration are which type of heat?
A. Dry Heat
B. Moist Heat C. Thermophilic
D. Procedure Heat
Which one of the following is NOT accomplished with Dry Heat?
A. Denatures Enzymes B. Dehydrated Microbes C. Oxidation
D. Composition
Autoclaving is the most effective method of moist heat sterilization.
True False
Boiling for 2 minutes will kill vegetative bacteria
True False
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Which is appropriate for Pasteurization?
A. 63° C for 30 min B. 72° C for 15 seconds C. 59 ° C for 20 minutes D. Both A &
B
Heat sensitivity can be affected by
A. container size B. cell density C. moisture content D. All of the above
Chapter 24
Chemical agents used on inanimate objects to lower the level of microbes on their surfaces are
A Antiseptics
B Bactericidal
C Disinfectants
Chemicals that cause temporary inhibition of growth are bacteriostatic agents
A True
B False
Chemicals used on living tissue to decrease the number of microbes are
A Antiseptics
B. Disinfectants
C Bactericidal
D. All of the above
E. Both A and C only
Antimicrobial agents must be matched to a specific organisms and environmental conditions.
A False
B True
Variables to consider in selecting an antimicrobial agent include
A pH
B solubility
C toxicity
D all of the above
What is an important criteria in evaluating the effectiveness of antimicrobial agents
A the concentration
B the pH of the solution
C length of contact
D. All of the above
E both A and C
Bacteriostatic agents cause temporary inhibition of growth
A True
B False
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How many strains are used for the use-dilution test for most purposes?
A 1
B 4
C 3
D None of the above
What type of technique is used for the use-dilution test
A Sterile
B Aseptic
C Clean
What is a disinfectant?
A. chemical objects used on inanimate objects to lower the level of microbes on their
surfaces
B. chemical objects used on objects to raise the level of microbes on surfaces
C. chemical objects used to show microbes on surfaces
D. chemical objects used to collect microbes on surfaces
What are the intervals of time used to inoculate bacteria on a Petri dish?
E. 5,10,15,and then 20 minutes
F. 2,4,6,8, and then 10 minutes
G. 1, 3,5,7 and then 9 minutes
H. 2.5, 5, 10, and then 20 minutes
Disinfectants and antiseptics affect bacteria in many ways. Those that result in bacterial death
are called :
F. bactericidal fluids
G. bactericidal waste
H. bactericidal sanitizers
I. bactericidal agents
Antimicrobials causing temporary inhibition of growth are:
A. bacteriostatic agents
B. bactericidal agents
C. bacteriostatic chemicals
D. bactericidal chemicals
True or false. The standard method for measuring the effectiveness of a chemical agent is the
American Official Analytical Chemist’s use-dilution test. True
True or false. The use-dilution test is limited to bactericidal compounds and cannot be used to
evaluate bacteriostatic compounds. True
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Wide varieties of chemicals called
microbes.
A. Antimicrobial
B. Disinfectants
C. Antiseptics
D. None of the above
agents are available for controlling the growth of
What are the variables to consider in selecting an antimicrobial agent?
A. pH
B. Solubility
C. Toxicity
D. Organic material present
E. Cost
F. All of the above
The effectiveness of disinfectant can be determined by the amount of resulting growth. T
In evaluating the effectiveness of antimicrobial agents, the concentration, length of contrast, and
whether it is lethal (-cidal) or inhibiting (-static) are the important criteria. T
Enumeration
When a doctor takes a swab from an infected wound:
a. It is to find out which organisms are present so he can select the proper antibiotic
b. There will usually be more than one organism present
c. Pure cultures need to be made to identify the organism(s)
d. All of the above
True or false - E. coli forms white colonies:
a. True
b. False
If three organisms each grew different color colonies on a plate, but all were Gram negative:
a. If you only did a Gram stain each organism would color differently because they are
different organisms
b. If you only did a Gram stain it would look as if there were only one organism
present
c. It is impossible to isolate each organism
d. The organisms are not transferrable to a petri dish for further examination
When inoculating cultures with a loop:
a. Poke the agar several times with the loop to create air holes
b. Make sure the loop is still red-hot when placing it in the agar
c. Straighten the loop so that it forms a needle-like point and it is no longer round at the
end
d. Sterilize the loop with a flame between samples to avoid unwanted
contamination
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If your colonies overlap after streaking to isolate the organisms with a zigzag like motion in a
petri dish:
a. You have created a culture that is difficult to examine the variations in organisms
b. You failed because perhaps there were too many organisms on the first quadrant
c. You failed because you dragged to long across quadrants of the petri dish
d. You failed because your zigzags were too narrow and did not cover enough surface
area
e. All of the above
True or false: When incubating the cultures, you should place them right side up so that
condensation is able to collect and provide water to the organisms
a. True
b. False
True or false: Cultures should be placed in the incubator upside-down so that removing it from
the incubator is easier and prevents accidental removal of the lid
a. True
b. False
One way to know if your organism isolation techniques were successful is:
a. There are multiple colors in each tube indicating multiple organisms
b. There is only one color in each tube
c. The tube has turned black
d. One can never know if their isolation efforts were successful
Who is called when there is an unusual amount of people that come in with the same illness?
A. The Center for Disease Control (CDC)
B. The Hospital
C. Urgent Care
What does the CDC do when there is an unusual amount of people that come in with the same
illness?
A. Interview the patients to find out if all the patients went to the same location right
before they got sick.
B. Count the number of patients in the hospital.
C. Examine Nursing techniques.
What is the measurement of how many living and dead organisms per ml are in the sample?
A. Cultures
B. Turbidity (cloudiness)
C. Community
What is the name of the machine that measures turbidity?
A. Microscope
B. Spectrophotometer
C. Incubator
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Using a spectrophotometer to measure turbidity is a(n) _________ estimate of cell density.
A. Direct
B. Indirect
What does the indirect method of enumeration of bacteria rely on?
A. The color of the sample
B. The number of the bacteria in the sample
C. The cloudiness of the sample
What is the Standard Plate Count (SPC)?
A. The number of colonies that grow on a plate.
B. The Direct Method of enumeration of bacteria
C. All of the above.
Before a standard plate count can be performed what must first happen?
A. A serial dilution
B. Staining
C. Culture count
Transmission and absorbance are:
A. Directly related
B. Inversely related
C. Neither
Cuvettes are made of:
A. Plastic
B. Optically pure glass
C. Cork
D. Plates
To make a standard plate count, how do you make a plate that has the colonies that are within
our ability to count?
A. We need to have a plate that does not have too many colonies to count.
B. Dilute the original plate and do a series of dilutions.
C. Let the bacteria grow for a few days and see how many grew.
D. All of the above
The number of colonies that are within our ability to count are
A. 10-300
B. 30-300
C. 100-300
D. 300-500
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If there are more than 300, some colonies may overgrow on other colonies and the count is not
accurate. If there are less than 30 colonies, there are not enough to count.
A. True
B. False
Which of the below four plates can be used to count colonies?
A. Bottle B, first plate = 1:10,000  800 colonies
B. Bottle B, second plate = 1:100,000  200 colonies
C. Bottle C, first plate = 1:1,000,000  20 colonies
D. Bottle C, second plate = 1:10,000,000  10 colonies
The formula for Concentration is Colony numbers x Dilution Factor= Concentration
A. True
B. False
How do you write the solution for concentration?
A. Write the number and box it
B. Convert to scientific notation
C. Convert to scientific notation and write units (org/ml)
What are the proper dilution sequence when making a dilution series?
A. 1:10-- 1:100-- 1:1000
B. 1:100-- 1:1000-- 1:10,000
C. 1:100—1:10,000—1:1,000,000
We counted 50 colonies on a plate that has 1:1000 dilution. What is the total number of
organisms in the original solution?
A. 50,000 org/ml5.0 x 104 org/ml
B. 5,000 org/ml5.0 x 103 org/ml
True or false. The more H+ ions, the more acidic the substance is.
True
What are organisms that grow best at pH 2 and 4 called
Thermophiles
Hydrophiles
autophiles
Acidophiles
What are organisms that grow best at pH 7 called?
Dreams
Acidophiles
metaphors
Neutrophiles
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What are organisms that grow best at pH 10-12 called?
Acidophiles
Neutrophiles
frogs
Alkaliniphiles
What does each unit change in pH represent?
A 1 fold difference in Hydrogen ions
A 10 fold difference in Hydrogen ions
A 20 fold difference in Hydrogen ions
A 100000 difference in H ions
What happens to cells that are placed in a suboptimal pH environment?
The proteins in their cell walls can become denatured.
The cells get sad
The tough cells get going
Nothing
What disease does alcaligenes faecalis cause?
Tourettes
Urinary tract infections
Stomach ulcers
Hand foot and mouth disease
True or false. Saccharomyces cerevisiae is used to make beer.
True
What type of organism is staph aureus?
Acidophile
Basophil
A neutrophile
An eosinophil
True or False. Saccharomyces cerevisiae is a neutrophile.
False (it is an acidophile)
What is effect of ultraviolet (UV) light on different types of bacteria?
A. UV light causes a bond to form between the two thiamine’s, and this stops
DNA replication.
B. This is the cause of death in the organism.
C. If an organism can produce endospores, it could survive UV light exposure
for a longer time.
D. All of the above
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When is an antiseptic used?
A. on tabletops
B. on tissue
What are the two kinds of antiseptics
A. topical and oral
B. Intramuscular and intravenous
What are disinfectants?
A. detergent
B. chemicals that are used on inanimate objects
With antimicrobials, are the largest zones of inhibition the most effective?
A. yes
B. sometimes
C. not necessarily
Antimicrobials are either:
A. Long or short spectrum
B. Tall or wide spectrum
C. Narrow or broad spectrum
D. Flat or oval spectrum
What type of antimicrobial is effective against Gram positive organisms?
A. Narrow spectrum
C. Broad spectrum
B. Long spectrum
D. Flat spectrum
What type of antimicrobial is effective against Gram positive and Gram negative organisms?
A. Binding spectrum
C. Wide spectrum
B. Narrow spectrum
D. Broad spectrum
If there are a lot of Gram negative bacteria in the blood stream and they are killed, what can be
released into the bloodstream and become deadly to the patient?
A. Exotoxins
C. Endomicrobials
B. Endomicrobials
D. Endotoxins
If your disc has a clear zone around it, which indicates no bacterial growth, this is called what?
A. Zone of detection
C. Zone of bacterial growth
B. Zone of inhibition
D. Zone of the clear zone
An antibiotic sensitivity table is called a what?
A. Snelling chart
B. Kirby chart
C. Antibiotic chart
D. Kirby-Bauer chart
The first treatment option for a patient is an antibiotic in which category?
A. Intermediate category
C. Synergistic category
B. Sensitive category
D. Effective category
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If a patient is allergic to the best drug, the second treatment option is to give _______
antibiotic(s) in which category?
A. Two, Sensitive category
C. One, intermediate category
B. One, sensitive category
D. Two, intermediate category
What is a nonsocomial infection?
a) Acquired from sharing needles for recreational drug use
b) Acquired from tattoos
c) Patient acquired it after admission to the hospital, did not have it before
d) Acquired from an open wound
How can nonscomial infections be avoided?
a) Proper handwashing techniques at all times
b) Washing hands only when exposed to blood or handling specimens
c) Wearing gloves at all times
d) Using hand sanitizer between patients
What are transient organisms?
a) Organisms that are always present on our skin
b) Organisms that are always present on our hands
c) Organisms that are on our hands for a short while
d) All of the above
How are we exposed to transient organisms?
a) Touching objects
b) Drinking after someone
c) Sharing a toothbrush
d) None of the above
What are resident organisms?
a) Organisms that are always present on our skin
b) Organisms that are always present on our hands
c) Organisms that are on our hands for a short while
d) All of the above
Are resident organisms harmful to us?
a) No, unless there is a break in the skin from which bacteria can enter
b) Yes, unless there is a break in the skin
c) A and B
d) B
Are resident organisms harmful to others?
a) No, unless there is a break in the skin from which bacteria can enter
b) Yes
c) A and B
d) None of the above
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True or False:
F- Washing your hands with water removes all transient organisms
F- Washing with soap and water removes all transient and resident organisms
T- Washing with soap and water is more effective than washing with water alone
T- Washing with soap and water for a short time removes transient organisms
What can you accomplish by washing your hands with soap and water?
A. Removes many more organisms than washing with water alone. Additionally,
washing for a short time will remove the transient organisms. You have to wash longer
to remove the resident organisms.
B. Rinses off a few organisms.
C. Removes all organisms: your hands are sterile.
D. None of the above
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