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WorksheetsChapter 13 Trivia
Total questions: 62
Worksheet time: 49mins
What is a current common use for phenolic compounds?
Disinfecting surfaces at home
Bathing infants
Antiseptic used before surgery
Preserving food
What chemical functional group defines phenolic compounds?
A chlorine, fluorine, or iodine atom
A positively charged nitrogen group
A carboxylic acid
A benzene ring with a hydroxyl group
How do heavy metals kill microbes?
Destabilizes the cell membrane
Binds to and inhibits enzymes
Denatures proteins and nucleic acids
Decreases the pH in the cytoplasm
What are the five common heavy metals used in microbial control?
Mercury (Hg), Silver (Ag), Zinc (Zn), Copper (Cu), and Nickel (Ni)
Cobalt (Co), Magnesium (Mg), Sodium (Na), Zinc (Zn), and Mercury (Hg)
Sodium (Na), Calcium (Ca), Copper (Cu), Nickel (Ni), and Silver (Ag)
Magnesium (Mg), Zinc (Zn), Sodium (Na), Calcium (Ca), and Lithium (Li)
Why are many heavy metals both antimicrobial and toxic to humans?
The disrupt cell membranes of any cell type.
They are able to diffuse across the membrane of any cell type.
They are not selective against enzymes from any particular species.
They damage DNA, which is present in all organisms.
What are the three halogens used in microbial control?
silver, copper, and nickel
chlorine, fluorine, and iodine
ethanol, isopropanol, and butanol
oxygen, hydrogen, and nitrogen
How do halogens kill microbes?
Inhibit protein synthesis
Add hydrocarbon groups to proteins and nucleic acids
Oxidize and destabilize macromolecules
Disrupt the cell membrane
What product is commonly used in clinical settings and contains a halogen?
povidone-iodine
isopropanol
carbolic acid
chloramine
What are the two most common alcohols used for disinfection and antisepsis?
ethanol and propanol
butanol and propanol
butanol and isopropanol
ethanol and isopropanol
What concentration of alcohol works best for disinfection and antisepsis?
100%
70%
37%
3%
What are the key chemical characteristics of a surfactant?
A positive charge and a negative charge
A hydrophilic portion and hydrophobic portion
A benzene ring and a hydroxyl group
An alkyl group and a carboxylic acid
How do soaps work to control the spread of microbes?
mechanically removes them from surfaces
completely kills all microbes on a surface
temporarily stops their growth
prevents microbes from forming aerosols
How do quaternary ammonium salts (quats) affect microbes?
causes the cytoplasm to congeal
mechanically removes them from surfaces
disrupts cell membranes
damages their DNA and proteins
Chlorhexidine and alexidine are examples of what class of microbial control agent?
alkylating agents
bisbiguanides
quaternary ammonium salts
heavy metals
What effect does chlorhexidine have on bacterial cells when given in high concentrations?
congeals the cytoplasm
damages DNA
disrupts cell membranes
inhibits enzymes
What effect does chlorhexidine have on bacterial cells when given in low concentrations?
congeals the cytoplasm
damages DNA
disrupts cell membranes
inhibits enzymes
How do alkylating agents kill microbes?
causes breaks in DNA
lowers the pH of the cytoplasm
adds hydrocarbon groups to proteins and nucleic acids
absorbs nearly all water from the cytoplasm
Why are alkylating agents only used as disinfectants or sterilants and not used as antiseptics?
They can burn the skin.
They can cause discoloration of the skin.
They can cause neurological problems.
They are carcinogenic.
How do peroxygens kill microbes?
disrupts cell membranes
oxidizes and destabilizes macromolecules
congeals the cytoplasm
binds to and inhibits enzymes
Which types of microbial control agent is NOT effective against enveloped viruses?
quats
alkylating agents
heavy metals
alcohols
What microbial control agent is effective against both Gram-positive and Gram-negative bacteria, viruses, and endospores?
peroxygens
phenolics
quats
bisbiguanides
What is a drawback of using sulfites as food preservatives?
They can cause cancer.
They can be harmful to the environment.
They do not kill all types of foodborne pathogens.
Some individuals are allergic to them.
What are two examples of natural chemical food preservatives?
nicin and natamycin
boric acid and penicillin
sorbic acid and nitrites
propionic acid and sodium benzoate
What would a phenol coefficient of 0.5 indicate?
The agent is more effective than phenol.
The agent is less effective than phenol.
The agent is similarly as effective as phenol
The agent does not work as a disinfectant.
In the disk-diffusion assay, which would indicate the more effective disinfecting agent?
a larger zone of inhibition
a smaller zone of inhibition
a thicker lawn
a thinner lawn
What method determines a chemical’s disinfection effectiveness on an inanimate surface?
disk-diffusion method
in-use test
phenol coefficient
use-dilution test
How much growth on either plate in the in-use test would indicate that a disinfectant solution is contaminated?
No growth
5 or more colonies
10 colonies or less
No more than 1 colony
Inanimate items that may harbor microbes and aid in disease transmission are called _____.
sterilants
fomites
contaminants
specimens
What factor most heavily influences the level of cleanliness required for a particular fomite?
what possible sources of contamination it has come into contact with
whether it could be harmful to the environment
what material it is made of, such as wood, plastic, or metal
whether it requires insertion into the human body
What is the system that rates microbes based on infectivity, ease of transmission, and disease severity?
Biosafety Levels
Biohazard Risk Assessments
Safety Data Sheets
Microbial Control Protocols
Which Biosafety Level describes organisms that pose very little risk to human beings?
BSL-1
BSL-2
BSL-3
BSL-4
Which Biosafety Level requires a respirator or working in a biosafety cabinet?
BSL-1
BSL-2
BSL-3
BSL-4
What is an example of a BSL-2 microbe?
Ebola virus
Most strains of Escherichia coli
Influenza virus
Some strains of Staphylococcus aureus
What is an example of an exotic pathogen that can be inhaled and causes deadly illness?
Mycobacterium tuberculosis
Marburg virus
Clostridium botulinum
Rhinovirus
What type of microbial control protocol completely kills all organisms on an item?
disinfection
pasteurization
sterilization
degerming
What type of microbial control protocol uses chlorine bleach, phenol, or glutaraldehyde?
disinfection
asepsis
sanitization
degerming
What type of microbial control protocol is used for commercial dishwashing and cleaning public bathrooms?
disinfection
commercial sterilization
sanitization
degerming
What is a chemical agent used to clean skin before surgery?
iodine
chlorine bleach
glutaraldehyde
detergents
What is the purpose of degerming?
to completely kill all microorganisms on a fomite
to physically remove microorganisms from skin or tissue
to prevent the transfer of microorganisms to an organic material
to slow the growth of microorganisms in food items
What process aims to reduce a population of 1012 endospores down to 1?
pasteurization
commercial sterilization
aseptic technique
sanitization
What type of microbial control agent kills bacteria?
bactericidal
virocidal
bacteriostatic
virostatic
What type of microbial control agent would inhibit the growth of mold, but not kill it?
bactericidal
virocidal
protostatic
fungistatic
What describes the trend of a typical microbial death curve?
parabolic
sigmoidal
logarithmic
linear
What is a D-value for a particular population of microbes?
the time it takes for 10% of organisms to die
the time it takes for 90% of organisms to die
the temperature it takes to remove 50% of organisms
the temperature it takes to remove 100% of organisms
What is a factor that would typically improve the effectiveness of a microbial control protocol?
lower temperature
higher concentration of disinfecting agent
presence of a biofilm
shorter exposure time
What is a factor that would typically hinder the effectiveness of a microbial control protocol?
higher temperature
higher concentration of disinfecting agent
presence of a biofilm
longer exposure time
What is the thermal death point of an organism?
the time needed to kill all microbes at a given temperature
the lowest temperature at which all microbes are killed in a 10-minute exposure
the highest temperature at which all microbes are killed in a 1-minute exposure
the time needed to kill 90% of microbes at a given temperature
What is the thermal death time of an organism?
the time needed to kill all microbes at a given temperature
the lowest temperature at which all microbes are killed in a 10-minute exposure
the highest temperature at which all microbes are killed in a 1-minute exposure
the time needed to kill 90% of microbes at a given temperature
What is the purpose of the high pressures used in autoclaving?
to enhance incineration of materials
to force hot steam to penetrate materials
to raise the achievable boiling temperature of liquids
to kill cells by crushing them
What is a typical temperature, pressure, and run time for an autoclave?
20 psi, 121 °C, 20 minutes
40 psi, 100 °C, 2 hours
2 psi, 171 °C, 40 minutes
800 psi, 210 °C, 4 minutes
Which is NOT a method used to ensure that optimum temperature was reached during an autoclave run?
heat shock
Diack tube
autoclave tape
biological spore test indicator
What is the main benefit of pasteurization?
maintains food quality while minimizing spoilage
allows storage of culture media at room temperature
kills all organisms in a food item
does not introduce harmful chemicals
Which type of pasteurization allows milk to be stored at room temperature for months or years without spoiling?
UHT
HTST
TSHU
HST
Which of the following is often preserved by snap freezing and storing at -70°C?
viruses
proteins
biological tissue samples
microbial growth media
What can be used to store specimens at -196°C?
dry ice
wet ice
freezer
liquid nitrogen
Which is NOT a way prevent microbial growth by lowering its water activity?
salting
desiccation
lyophilization
sonication
What method of microbial control involves freezing cells under a vacuum?
HEPA filtration
desiccation
lyophilization
sonication
What is a common application of ionizing radiation in controlling microbial growth?
to sterilize biological tissue samples
to clean skin before surgery
to sterilize many packaged materials
to treat a systemic infection
Which type of radiation works by creating many thymine dimers in DNA?
visible light
gamma rays
X-rays
UV light
What method of microbial control involves exposing cells to ultrasonic waves?
pasteurization
desiccation
lyophilization
sonication
What method of microbial control is used to remove microbes from air?
HEPA filtration
membrane filtration
sonication
lyophilization
What is a typical pore size of a membrane filter?
30 μm
100 μm
0.2 μm
0.04 μm
