Chpt 9 control of growth q & a
Alcohol is most effective when used as a ________ solution. A. 95% B. 100% C. 60% D. 70% E. 25%
70%
Which concentration of ethanol is the most effective bactericide? A. 100% B. 70% C. 50% D. 40% E. 30%
70%
A nurse is degerming a patient's arm before giving a vaccination. Which of these concentrations of alcohol is most effective? A. 100% B. 75% C. 50% D. 25%
75% Alcohols work by denaturing proteins, and this process requires water. Generally, the most effective alcohol concentration is 70%.
The decimal reduction time is the time required to kill __________ percent of a bacterial population
90%
By definition, a tincture contains alcohol. Why would a tincture of an antiseptic be more effective than an aqueous solution? A. Alcohol contributes to the effectiveness of an antiseptic because it denatures proteins. B. Alcohol contributes to the effectiveness of an antiseptic because it dissolves lipids. C. Answers A and B are both correct. D. Neither answer A nor B is correct
Answers A and B are both correct
Treatment is directed at living tissue A. sterilization B. Antisepsis C. Disinfection D. Degerming E. Sanitization
Antisepsis
Kills microorganisms A. Biocides B. fungicides C. virucide D. bacteriostasis E. spesis
Biocides
The mechanical removal of most microbes in an area A. sterilization B. Antisepsis C. Disinfection D. Degerming E. Sanitization
Degerming
When skin is cleaned with alcohol prior to an injection A. sterilization B. Antisepsis C. Disinfection D. Degerming E. Sanitization
Degerming
The destruction of vegetative pathogens that do not form endospores A. sterilization B. Antisepsis C. Disinfection D. Degerming E. Sanitization
Disinfection
Some microbes are very resistant to antimicrobial chemicals. Which of the following would be the easiest to kill? A. Mycobacterium tuberculosis B. E. coli. C. cysts of protozoa D. Pseudomonas aeruginosa E. Clostridium endospores
E. coli
True/ False Microorganisms placed in high concentrations of salts and sugars undergo lysis.
False
True/ False The pH of the medium has no effect on the activity of the disinfectant being applied.
False
True/False All bacteria die at once when they are exposed to heat or chemical treatment
False
True/False Iodine is one of the least effective antimicrobial chemicals, effective only against certain very sensitive strains of bacteria.
False
True/False Most viruses are highly resistant to disinfectants and antiseptics
False
True/False Soap is ineffective in killing bacteria. Therefore, hand washing is a rather ineffective measure in preventing disease transmission.
False
True/False UV radiation and x-ray radiation are similar in that they damage DNA and have a high penetrating power
False
Why would filter sterilization be used rather than heat, such as autoclaving? A. Filter sterilization is less expensive than autoclaving. B. Filter sterilization is used when the contents of the liquid could be harmed by heat. C. Filter sterilization is more effective than autoclaving
Filter sterilization is used when the contents of the liquid could be harmed by heat
__________ bacteria may survive pasteurization
Heat resistant
60 minutes
In the figure, what is the thermal death time? A. 150°C B. 120 minutes C. 100°C D. 60 minutes E. The answer cannot be determined.
Which of the following is a limitation of the autoclave? A. It requires an excessively long time to achieve sterilization. B. It cannot be used with glassware. C. It cannot inactivate viruses. D. It cannot be used with heat-labile materials. E. It cannot kill endospores
It cannot be used with heat-labile materials
_______________ is a process used to destroy pathogens in food and drinks. It must be done at a lower temperature than other methods so that _______________. A. autoclaving; beneficial microorganisms are not killed B. Pasteurization; beneficial microorganisms are not killed C. autoclaving; the taste of the food or drink will not be altered D. Pasteurization; the taste of the food or drink will not be altered
Pasteurization; the taste of the food or drink will not be altered
You are preparing a medium for growing fastidious bacteria and must add several heat-labile solutions of growth factors. Which of the following is an appropriate strategy for preparing and sterilizing this medium? A. Prepare and autoclave the medium before adding the growth factors. After the medium has cooled, filter sterilize and aseptically add the growth factors. B. Use UV radiation to sterilize this medium. C. Use dry heat to sterilize the medium. D. Prepare the medium, add the growth factors, and autoclave. E. Pasteurize the medium.
Prepare and autoclave the medium before adding the growth factors. After the medium has cooled, filter sterilize and aseptically add the growth factors.
__________ ammonium compounds are less effective against gram-negative bacteria and more effective against gram-positive bacteria.
Quaternary
Treatment intended to lower microbial counts on eatting and drinking utensils to safe public health levels A. sterilization B. Antisepsis C. Disinfection D. Degerming E. Sanitization
Sanitization
When a restaurant washes its dishes in a high-temp dishwasher A. sterilization B. Antisepsis C. Disinfection D. Degerming E. Sanitization
Sanitization
A nurse is working in southeast Asia, where the incidence of Mycobacterium tuberculosis is very high. Why is it necessary to select a specific method of disinfection for this organism ? A. The presence of a capsule makes this organism more resistant to disinfectants. B. Bacterial endospores made by this organism are resistant to disinfectants. C. The presence of an envelope makes this organism relatively resistant to disinfectants. D. The waxy, lipid-rich components of the cell wall make this organism relatively resistant to disinfectants.
The waxy, lipid-rich components of the cell wall make this organism relatively resistant to disinfectants
________ is a compound found in antimicrobial soaps that targets gram-positive bacteria. A. Sodium nitrate B. Mercuric chloride C. Formaldehyde D. Triclosan E. Hydrogen peroxide
Triclosan
True/ False Heating is the most common use for killing microbes
True
True/ False Pseudomonas has been found growing in quaternary ammonium compounds (quats).
True
True/False Ethylene oxide gas is used to sterilize medical equipment that might be damaged by exposure to the heat of autoclaving
True
True/False Ionizing radiation can be used to sterilize some foods such as spices, meat, and fruits and vegetables.
True
True/False The presence of organic matter, such as blood or saliva, may impair the action of antimicrobial chemicals
True
True/False Times required for sterilization in an autoclave are shorter than those required in a dry oven because moist heat penetrates biological specimens more effectively than does dry heat.
True
While waiting for your meal at a restaurant, you read the information on the creamer containers at your table and notice that they do not need to be refrigerated. You are surprised, because dairy products typically must be kept cold to prevent spoilage. How were these products treated to eliminate microbial growth and prevent spoilage? A. UHT treatment B. chemical preservatives C. gamma irradiation D. pasteurization
UHT treatment Ultra-high-temperature (UHT) is a treatment that essentially sterilizes the product
Which of the following shows the moist heat methods in order of the temperature used (highest to lowest)? A. Ultrahigh>Boiling>Autoclave>Batch Pasteurization B. Ultrahigh>Autoclave>Boiling>Batch Pasteurization C. Autoclave>Ultrahigh>Batch Pasteurization>Boiling D. Ultrahigh> Boiling>Batch Pasteurization >Autoclave
Ultrahigh>Autoclave>Boiling>Batch Pasteurization
Which of the following pairs is mismatched? A. organic acids food preservation B. H2O2 open wounds C. alcohols open wounds D. Ag wound dressings E. CuSO4 algicide
alcohols open wounds
Oxidizing agents, such as hydrogen peroxide, are useful for irrigating deep wounds where released oxygen will inhibit the growth of __________.
anaerobic bacteria
The chemical disinfection of living tissue is known as A) antisepsis B) degerming
antisepsis Antisepsis is the chemical disinfection of living tissues
Which method achieves sterilization? A) pasteurization B) the autoclave
autoclave The autoclave uses heat under pressure to allow temperatures above the boiling point of water to be reached.
Which of the following treatments achieves sterilization? A. pasteurization B. freezing C. bringing water to a boil D. autoclaving
autoclaving Autoclaving destroys all living organisms, spores, and endospores, thereby sterilizing heat-stable items
Some antimicrobial treatments kill microbes; some inhibit growth. Which term refers to an agent that inhibits bacterial growth? A. germicidal B. bacteriostatic C. homeostatic D. fungicidal E. bacteriocidal
bacteriostatic
Which of the following pairs of terms is mismatched? A. virucide - inactivates viruses B. fungicide kills yeasts and molds C. sterilant destroys all living microorganisms D. bacteriostatic kills vegetative bacterial cells E. germicide - kills microbes
bacteriostatic kills vegetative bacterial cells
All of the following are examples of microbial control using heavy metals except ________. A. mouthwash solution containing zinc chloride. B. burn treatment using silver-sulfadiazine ointment C. algae control in swimming pools using copper sulfate D. benzoyl peroxide used for acne treatment E. antiseptic solution containing mercurochrome
benzoyl peroxide used for acne treatment
What group of chemicals does triclosan fall into? A) a halogen B) a bisphenol
bisphenol Triclosan is a bisphenol found in many antimicrobial products, including antibacterial soaps
Which of the following disinfectants acts by disrupting the plasma membrane? A. heavy metals B. halogens C. bisphenols D. soaps E. aldehydes
bisphenols
__________ is a common household disinfectant that has been used to disinfectant everything from dairies to drinking water.
bleach
How does alcohol kill bacteria? A) by denaturing proteins B) by inhibiting DNA synthesis
by denaturing proteins
Which one of the following substances is effective against bacterial endospores? A. bisphenols B. quaternary compounds C. mercury D. chlorine
chlorine
Which one of these halogen compounds would be considered an antiseptic? A. hypochlorous acid B. calcium hypochlorite C. chlorine dioxide D. chlorine gas
chlorine dioxide
Application of heat to living cells can result in all of the following EXCEPT A. alteration of membrane permeability. B. denaturation of enzymes. C. decreased thermal death time. D. damage to nucleic acids. E. breaking of hydrogen bonds
decreased thermal death time
What is removal of microbes from skin by mechanical cleansing or by an antiseptic called? A) sanitization B) degerming
degerming Degerming removes microbes from the skin, such as when an alcohol swab is used prior to an injection.
Moist heat kills microbes by __________ of cellular components
denaturation
The preservation of beef jerky from microbial growth relies on which method of microbial control? A. filtration B. lyophilization C. desiccation D. supercritical CO2 E. ionizing radiation
desiccation
Sterilization is the ________. A. destruction of all life-forms B. destruction of all forms of microbial life except endospores C. effective removal of all microbes on a surface D. control of all microbial growth E. same as sanitization
destruction of all life-forms
All of the following methods are used for food preservation except ________. A. dessication B. osmotic pressure C. direct flaming D. deep freezing E. commercial canning
direct flaming
What is the best definition of sterilization? A. removal of unwanted microorganisms B. removal of viruses C. elimination of bacteria D. elimination of all microorganisms
elimination of all microorganisms
Which of the following chemical agents is used for sterilization? A. phenolics B. ethylene oxide C. alcohol D. soap E. chlorine
ethylene oxide
Which one of these chemical treatments kills cells by causing cross-linking of nucleic acids and proteins and inhibits vital cellular functions? A. alcohol B. ethylene oxide C. heavy metals D. soaps and detergents
ethylene oxide
True/False Household bleach contains chlorhexidine as the active ingredient
false
Which of the following is not a major target for action of antimicrobials? A. proteins B. nucleic acids C. enzymes D. cell membranes E. flagella
flagella
A chemical that reduces spoilage in fruit by destroying fungi, but does not appear to affect other microbes, would be called a __________. A. fungicidal agent B. fungistatic agent C. sterilant D. bactericidal agent
fungicidal agent
Which one of these products is most useful for disinfecting medical instruments? A. iodine B. glutaraldehyde C. alcohols D. soap and detergents
glutaraldehyde
To which category do iodine and chlorine belong? A) biguanide B) halogen
halogen
Which of the following results in lethal damage to nucleic acids? A. heat B. radiation C. certain chemicals D. heat and radiation E. heat, radiation, and some chemicals
heat, radiation, and some chemicals
Which one of the following physical methods of microbial control is bactericidal? A. refrigeration B. deep-freezing C. desiccation D. incineration
incineration
When iodine is combined with an organic molecule, it is called A) an iodophor B) tincture
iodophor When iodine is combined with an organic molecule, it is called an iodophor.
Which of the following is the best method to sterilize heat-labile solutions? A. dry heat B. autoclave C. pasteurization D. freezing E. membrane filtration
membrane filtration
What is the typical mechanism of action for chemical food preservatives? A. oxidation B. surface-active agents for removal of microbes C. metabolic inhibition D. disruption of plasma membranes
metabolic inhibition
Which type of radiation is least effective in killing microbes? A. gamma rays B. microwaves C. x-rays D. high-energy electron beams E. ultraviolet rays
microwaves
Which of the following are NOT typically destroyed by antimicrobial agents? A. nuclei B. proteins C. nucleic acids D. plasma membranes
nuclei Bacteria do not contain nuclei, and since most disinfectants target bacteria, nuclei are not a typical target
Recently, silver has been considered in new applications for microbial control, such as impregnating surgical dressings and infusing food containers with silver. These new applications are important because silver is__________. A. useful as a surface-active agent B. effective in dissolving lipids in the plasma membrane C. oligodynamic and unaffected by antimicrobial resistance D. effective as an oxidizing agent
oligodynamic and unaffected by antimicrobial resistance
Which method of control is it when we use concentrated salt solutions to cure meats? A) osmotic pressure B) high pressure
osmotic pressure
Which of the following does not kill endospores? A) autoclaving B) pasteurization
pasteurization Pasteurization does not kill endospores
Which of the following infectious agents challenges current sterilization strategies that have been accepted and in use for decades? A. endospores B. mycobacteria C. HIV D. methicillin-resistant Staphylococcus aureus (MRSA) E. prions
prions
Which of the following is least likely to be damaged by exposure to gamma radiation? A. protozoa B. prions C. bacteria D. fungi E. viruses
prions
Disinfection methods have NOT completely solved the problem of destroying which of the following? A. prions B. endospores C. protozoan cysts D. enveloped viruses
prions Prions are especially difficult to destroy. Incineration has been used for infected organisms. but effective treatment for equipment is still being determined. Even autoclaving requires the addition of sodium hydroxide.
Which of these microbes is the most difficult to destroy using either chemical or physical methods? A. prions B. HIV C. MRSA (methicillin-resistant Staphylococcus aureus) D. bacterial endospores
prions Prions are the most difficult infectious particles to destroy. Currently, a combination of very high temperature and sodium hydroxide is used
Which of the following correctly describes antisepsis? A. destruction of vegetative microorganisms on inanimate surfaces B. removal of vegetative microorganisms from living tissue C. reduction of microbial cells on eating or drinking utensils D. destruction of all organisms on any surface
removal of vegetative microorganisms from living tissue
Which type of treatment is it when a restaurant washes its eating utensils? A) sanitization B) degerming
sanitization Sanitization lowers the microbial count to safe public health levels
An antiseptic is used to remove microbes from ________. A. restaurant glassware B. food preparation areas C. toilet surfaces D. skin, before an injection E. foods, before canning them
skin, before an injection
What is the main effect of refrigeration on microbes? A) kills microbes B) slows microbial growth
slows microbial growth
Food is subjected to enough heat to destroy the endospores A. sterilization B. Antisepsis C. Disinfection D. Degerming E. Sanitization
sterilization
The destruction or removal of all forms of life A. sterilization B. Antisepsis C. Disinfection D. Degerming E. Sanitization
sterilization
Usually done by steam under pressure or ethylene oxide A. sterilization B. Antisepsis C. Disinfection D. Degerming E. Sanitization
sterilization
Destroying all forms of microbial life is known as A) disinfection B) sterilization
sterilization Sterilization is the destruction of all forms of microbial life
What would be an appropriate use of ultra-high-temperature treatment? A) sterilizing rubber tubing B) sterilizing coffee creamers.
sterilizing coffee creamers
What does UV radiation damage in a cell? A) proteins B) the DNA
the DNA
Pasteurized milk in an unopened container spoils in the refrigerator. A sample reveals the presence of microorganisms. The most likely explanation is ________. A. the microbes that survived pasteurization were able to grow at 4°C. B. the microbes are pathogens C. the pasteurization process was ineffective D. a leak in the milk carton allowed microbes to enter E. pasteurization-resistant mutants developed after pasteurization
the microbes that survived pasteurization were able to grow at 4°C.
Which of these is not a characteristic of the autoclave? A. the use of moist heat B. the requirement for long (hours) exposure times C. the ability to sterilize solutions with endospores D. the use of high temperatures E. the use of high pressures
the requirement for long (hours) exposure times
For which of the following would it be appropriate to use high-energy electron beams as a means to control microbial growth? A) to sterilize disposable dental supplies B) to disinfect the air going into a nursery
to sterilize disposable dental supplies
Which of these chemicals inhibits an enzyme required for synthesis of membrane lipids? A. chlorine B. hydrogen peroxide C. ozone D. triclosan
triclosan
True/False The most commonly used iodophor is Betadine
true
Packages of milk and coffee creamers may be stored without refrigeration if they have been sterilized by ________. A. boiling B. ultra-high-temperature (UHT) treatment C. autoclaving D. treatment with phenol E. high-temperature short-time (HTST) pasteurization
ultra-high-temperature (UHT) treatment
For control of microbial growth on a surface, which of these conditions is LEAST likely to interfere with the effectiveness of an antiseptic or disinfectant? A. presence of organic matter B. high numbers of microbes C. presence of biofilms D. warm environmental conditions
warm environmental conditions
When would it be appropriate to use glutaraldehyde? A) when embalming corpses B) when disinfecting water for swimming pools
when embalming corpses
Pasteurization was first used by Pasteur to control spoilage of ________. A. milk B. yogurt C. wine D. cheese E. canned foods
wine
The following may be listed on the ingredients of your favorite snack food. Which of these products is not antimicrobial? A. sodium benzoate B. sorbic acid C. xanthan D. potassium sorbate E. calcium propionate
xanthan
During a flood, a community's well water system is contaminated with a pathogenic fungus. If the residents boil their water for 15 minutes prior to consumption, will they be protected? A. yes, most likely B. probably not C. definitely not
yes, most likely
