Deck 11: Physical and Chemical Control of Microbes

Question 1

Microbial death occurs when there is _______.

A) no movement
B) no reproduction
C) a change in appearance
D) a decrease in size
E) All of the choices occur.

Answer 1

no reproduction

Question 2

Each of the following is a target of antimicrobial agents except ______.

A) cell walls
B) cell membranes
C) ribosomes
D) cellular proteins
E) cytoplasm

Answer 2

cytoplasm

Question 3

Which is correct regarding the rate of microbial death?

A) Cells die at increasingly greater rates.
B) Only older cells die in a culture.
C) Cells in a culture die at a constant rate.
D) Upon contact with the control agent, all cells die at one time.
E) Cells become metabolically inactive but are never killed.

Answer 3

Cells in a culture die at a constant rate.

Question 4

Which of the following factors will in?uence the action of microbial agents?

A) The number of microorganisms
B) The type of microorganisms present
C) Temperature and pH
D) Mode and dosage of the agent
E) All of the choices will in?uence the action.

Question 5

Which of the following types of control agents would be used to achieve sterility?

A) Virucide
B) Bactericide
C) Germicide
D) Sporicide
E) Fungicide

Question 6

The process that destroys or removes all microorganisms and microbial forms, including bacterial endospores, on inanimate objects is ______.

A) disinfection
B) sterilization
C) antisepsis
D) sanitization
E) degermation

Question 7

Agents that can denature microbial proteins include all of the following except ______.

A) moist heat
B) alcohol
C) acids
D) metallic ions
E) X rays

Question 8

The alcohol wipe used on a patient's skin before an injection is an example of ______.

A) antisepsis
B) disinfection
C) sterilization
D) decontamination
E) sanitization

Question 9

Surfactants work by _______.

A) coating the organism preventing interaction with its environment
B) blocking transport into the organism
C) blocking transport out from the organism
D) disrupting membrane integrity

Question 10

Physical agents for controlling microbial growth include all of the following except ______.

A) ultraviolet radiation
B) boiling water
C) pasteurization
D) hydrogen peroxide

Question 11

The method of removing vegetative life forms from living surfaces is termed ______.

A) antisepsis
B) disinfection
C) sterilization
D) decontamination

Question 12

Which of the following microbial forms has the highest resistance to physical and chemical controls?

A) Naked viruses
B) Protozoan cysts
C) Fungal spores
D) Bacterial endospores
E) Yeast

Question 13

Some microbial control agents are able to _____ cell proteins by breaking bonds that maintain the native state, the three-dimensional con?guration of the proteins.

A) bind
B) mutate
C) denature
D) dissolve

Question 14

The removal of all life forms from inanimate objects is termed ______.

A) antisepsis
B) disinfection
C) sterilization
D) decontamination
E) degerming

Question 15

The method of removing vegetative microbial life forms and debris to reduce contamination to safe levels is termed ______.

A) antisepsis
B) disinfection
C) sterilization
D) decontamination
E) sanitization

Question 16

Scrubbing or immersing the skin in chemicals to reduce the numbers of microbes on the skin is _______.

A) disinfection
B) sterilization
C) sanitization
D) degermation

Question 17

The use of a physical or chemical process to destroy vegetative pathogens on inanimate objects is ______.

A) disinfection
B) sterilization
C) antisepsis
D) sanitization
E) degermation

Question 18

Which of the following does not affect microbial nucleic acids?

A) Moist heat
B) Ultraviolet light
C) X rays
D) Ethylene dioxide
E) Formaldehyde

Question 19

The use of chemical agents directly on exposed body surfaces to destroy or inhibit vegetative pathogens is _______.

A) disinfection
B) sterilization
C) antisepsis
D) sanitization

Question 20

The easiest microbial forms to kill or inhibit are ______.

A) naked viruses
B) vegetative bacteria and fungi
C) endospores
D) protozoan cysts
E) mycobacteria and staphylococci

Question 21

Dry heat _______.

A) is less e?cient than moist heat
B) cannot sterilize
C) includes tyndallization
D) is used in devices called autoclaves
E) will sterilize at 121°C for 15 minutes

Question 22

The shortest time required to kill or inactivate all the microbes in a sample at a speci?ed temperature is called the _______.

A) thermal death point (TDP)
B) thermal death time (TDT)
C) sporicidal time
D) death phase point

Question 23

Which control method would not be a suitable choice for killing Mycobacterium in a capped culture tube?

A) Ultraviolet (germicidal) light
B) Gamma rays
C) 121°C at 15 psi for 15 minutes
D) 160°C for 2 hours
E) All of the choices are correct.

Question 24

What instrument is most effective for pressure-temperature sterilization?

A) Oven
B) Autoclave
C) Bunsen burner
D) Water-bath
E) Incubator

Question 25

Which of the following items are typically irradiated in order to kill microbes?

A) Cured meats
B) Human tissues such as heart valves and skin
C) Operating room air
D) Surgical gloves
E) All of the choices are correct.

Question 26

The lowest temperature needed to kill or inactivate all microbes in 10 minutes is the ______.

A) thermal death point (TDP)
B) thermal death time (TDT)
C) sporicidal time
D) death phase point

Question 27

Pasteurization _______.

A) kills all vegetative forms
B) reduces the number of vegetative forms
C) reduces the number of endospores
D) increases food nutrient value
E) is used to sterilize food products

Question 28

Intermittent sterilization, which uses 3 days of lower temperature steam for short periods of time, is also called ______.

A) pasteurization
B) incubation
C) tyndallization
D) disinfection
E) desiccation

Question 29

_____ heat is more rapidly effective and e?cient compared to _____ heat.

A) High; dry
B) High; moist
C) Dry; moist
D) Moist; dry
E) Moist; high

Question 30

The minimum sterilizing conditions in a steam autoclave are _______.

A) 71.6°C for 15 seconds
B) 63°C for 30 minutes
C) 100°C for 30 minutes
D) 160°C for 2 hours
E) 121°C at 15 psi for 15 minutes

Question 31

A method for sterilizing milk, called _____ treatment, uses 134°C for 1 to 2 seconds.

A) pasteurization
B) batch pasteurization
C) ?ash pasteurization
D) ultra high temperature
E) tyndallization

Question 32

_____ radiation excites atoms to a higher energy state within molecules such as DNA, which leads to the formation of pyrimidine dimers.

A) Gamma
B) Infrared
C) Ionizing
D) Particle
E) Ultraviolet

Question 33

Removal of moisture by dehydration is called ______.

A) pasteurization
B) ?ash freeze
C) lyophilization
D) desiccation
E) sterilization

Question 34

Disinfection of beverages such as apple juice, milk, and wine is optimally achieved by ______.

A) ?ltration
B) moist heat autoclave
C) pasteurization
D) chlorination
E) boiling water

Question 35

Which of the following forms of radiation are in order from the most penetrating to the least penetrating?

A) X ray, gamma, cathode
B) Cathode, gamma, X ray
C) Cathode, X ray, gamma
D) Gamma, cathode, X rays
E) Gamma, X rays, cathode

Question 36

Placing organisms at 4^oC is ______.

A) bactericidal
B) bacteriostatic
C) decontamination
D) sterilization
E) germicidal

Question 37

Sterilization is achieved by _______.

A) ?ash pasteurization
B) hot water
C) boiling water
D) steam autoclave
E) All of the choices are correct.

Question 38

Vials of microorganisms that undergo the freeze-drying process, called _____, will remain preserved and viable for years.

A) desiccation
B) ?ash freeze
C) lyophilization
D) pasteurization
E) sterilization

Question 39

Electrons are ejected from atoms in cells when organisms are exposed to ______.

A) desiccation
B) ultraviolet light
C) ethyl alcohol
D) hydrogen peroxide
E) gamma rays and X rays

Question 40

Which of the following is not a primary target of milk pasteurization?

A) Salmonella
B) Campylobacter jejuni
C) Lactobacillus
D) Listeria monocytogenes
E) Brucella

Question 41

Which of the following is not a heavy metal?

A) Tincture of iodine
B) Merthiolate
C) Silver nitrate solution
D) Zinc
E) Mercurochrome

Question 42

Heavy metals work by _______.

A) mutating DNA
B) binding to DNA
C) dissolving the cell wall
D) inactivating proteins
E) rupturing the cell membrane

Question 43

Which of the following is not used as an antiseptic?

A) Chlorhexidine
B) Iodophor
C) Merthiolate
D) 3% hydrogen peroxide
E) Aqueous glutaraldehyde

Question 44

The chemical agent/s that produce/s highly reactive hydroxyl-free radicals and also decomposes to O? gas is _______.

A) hydrogen peroxide
B) chlorhexidine
C) iodophors
D) Cidex
E) cationic detergents

Question 45

The compound that is an organic base containing chlorine and two phenolic rings, and is used increasingly for wound degerming, neonatal washes, hand scrubbing, and prepping surgical skin sites is _______.

A) formalin
B) carbolic acid
C) chlorhexidine
D) triclosan
E) a quaternary ammonium compound

Question 46

_____ is a control method that removes microorganisms rather than inhibiting or killing them.

A) Disinfection
B) Boiling
C) Filtration
D) Sterilization
E) Radiation

Question 47

The use of ?ltration for sterilization _______.

A) uses heat and ?ltration
B) relies on gravity
C) can remove viruses
D) removes toxins
E) leaves behind endospores

Question 48

Iodophors include ______.

A) alcohols
B) chlorhexidine
C) tincture of iodine
D) chloramines
E) betadine

Question 49

Which of the following is not a factor that affects germicidal activity?

A) Material being treated
B) Length of exposure
C) Strength of the germicide
D) Microorganism being treated
E) All of the choices are factors.

Question 50

Which of the following germicides is/are also sporicidal?

A) Betadine
B) Chlorine
C) Phenolics
D) Chlorhexidine
E) All of the choices except phenolics.

Question 51

Which of the following is not true of chloramines?

A) They form trihalomethanes with organic compounds.
B) They are safer than free chlorine.
C) They contain chlorine.
D) They can sanitize and disinfect.
E) They are used to treat wounds and skin surfaces.

Question 52

Hydrogen peroxide is _______.

A) sporicidal
B) fungicidal
C) bactericidal
D) virucidal
E) All of the choices are correct.

Question 53

All of the following act as surfactants except ______.

A) iodine
B) detergents
C) alcohols
D) quaternary ammonia
E) soaps

Question 54

Alcohols _______.

A) denature proteins when in a 50-95% alcohol-water solution
B) disinfect items when soaking method is utilized
C) are skin degerming agents
D) at 50% or higher concentrations dissolve cell membrane lipids
E) All of the choices are correct.

Question 55

All of the following are phenols or phenolics except ______.

A) hexachlorophene
B) Lysol
C) cresols
D) triclosan
E) Zephiran

Question 56

_____ solution was introduced in the late 19th century for preventing gonococcal infections in a newborn's eyes after exposure to the mother's infected birth canal.

A) Merthiolate
B) Zinc oxide
C) Silver nitrate
D) Triclosan
E) Betadine

Question 57

All of the following pertain to hypochlorites except _______.

A) they are found in iodophors
B) they are used to disinfect dairy, restaurant, and medical equipment
C) they are found in common household bleach
D) they release hypochlorous acid in solution
E) they cause denaturation of enzymes

Question 58

HEPA ?lters are used to remove microbes from _______.

A) air
B) liquids
C) human tissues
D) medical instruments
E) All of the choices are correct.

Question 59

_____ is a halogen used in gaseous and liquid form for large scale disinfection of drinking water and sewage.

A) Iodine
B) Chlorine
C) Bromine
D) Fluorine
E) Betadine

Question 60

Which of the following is not true of glutaraldehyde?

A) It cross-links proteins on cell surfaces.
B) It is classi?ed as a carcinogen.
C) It does not damage plastics.
D) It inactivates viruses.
E) It inactivates endospores in 3 hours.

Question 61

Antimicrobial agents can target the cell wall by _______.

A) blocking its synthesis
B) digesting it
C) denaturing proteins
D) All of the choices are correct.

Question 62

Which of the following acids is not used to destroy or inhibit microbial cells in food?

A) Lactic acid
B) Benzoic acid
C) Phosphoric acid
D) Propionic acid
E) Acetic acid

Question 63

Using a HEPA ?lter in a vacuum or furnace is an example of which microbial control method?

A) Chemical agent
B) Gases
C) Surfactant
D) Dry control

Question 64

When a control agent targets the metabolic processes of microbial cells, active younger cells
typically die more rapidly than older cells.

Question 65

Ionizing radiation is more effective than nonionizing radiation in killing or inactivating microbes.

Question 66

Which of the following represents the use of osmotic pressure as a microbial control method?

A) Bleaching a kitchen counter
B) Salting of meat
C) Rinsing of a cut with Betadine
D) Exposing dental equipment to UV light

Question 67

The presence of organic matter such as saliva and pus can interfere with the actions of
disinfectants.

Question 68

A microorganism that is not motile and has stopped metabolizing is considered dead.

Question 69

Pasteurization is used to sterilize milk.

Question 70

All of the following are alkylating control agents except ______.

A) iodophor
B) propylene oxide
C) ethylene oxide
D) glutaraldehyde
E) formaldehyde

Question 71

Which is mismatched?

A) Merthiolate - silver
B) Sodium hypochlorite - chlorine
C) Formalin - formaldehyde
D) Iodophor - iodine
E) Benzalkonium chloride - quaternary ammonium compound

Question 72

In lab, inoculating loops are sterilized using ______.

A) gas sterilization
B) ?ltration
C) moist heat
D) chemicals
E) incineration

Question 73

Endospores can be inactivated by _______.

A) dry heat at 170°C for 2 hours
B) incineration
C) glutaraldehyde for 3 or more hours
D) ethylene oxide for 3 or more hours
E) All of the choices are correct.

Question 74

All microbicidal agents are sterilants.

Question 75

Bacteriostatic agents kill bacterial cells.

Question 76

The sterilizing gas used in chemiclaves is ______.

A) chlorine dioxide
B) ethylene oxide
C) glutaraldehyde
D) formaldehyde
E) iodophor

Question 77

Most microbial contaminants of food are killed or inactivated at freezing temperatures.

Question 78

Ethylene oxide is ______.

A) used as an antiseptic against anaerobes
B) the active agent in household bleach
C) sporicidal
D) a halogen
E) only effective with high heat

Question 79

Pasteurization does not inactivate endospores or thermoduric microbes.

Question 80

Prions require more extensive methods of sterilization than are needed for bacterial endospores.