Chapter 7 Microbiology

Which one of the following does NOT belong with the others? A) Acid-anionic detergents B) Benzoic acid C) Supercritical CO2 D) Pasteurization E) Peracetic acid

A) Acid-anionic detergents

Which of the following substances is NOT effective against nonenveloped viruses? A) Alcohol B) Chlorine C) Ethylene oxide D) Ozone E) All are equally effective.

A) Alcohol Alcohols used in many hand sanitizers no effect on endospores and nonenveloped viruses

Which of the following substances is NOT used to preserve foods? A) Biguanides B) Nisin C) Potassium sorbate D) Sodium nitrite E) Sodium propionate

A) Biguanides chemical food preservatives sulfur dioxide prevents wine spoilage organic acids- inhibit metabolism sorbic acid, benezoic acid, and calcium propinate prevent molds in acidic foods nitrites and nitrates prevent endospore germination

Which of the following will NOT destroy prions? A) Boiling B) Incineration C) NaOH + autoclaving at 134°C D) Proteases E) All of the above destroy prions.

A) Boiling

Glutaraldehyde is considered one of the most effective disinfectants for hospital use. Which of the following statements about glutaraldehyde is false? A) Stains and corrodes B) Is safe to transport C) Acts rapidly D) Is not hampered by organic material E) Attacks all microorganisms

A) Stains and corrodes useful disenfectant should be able to nonstain and noncorrosive

Which of the following best describes the pattern of microbial death? A) The cells in a population die at a constant rate. B) All the cells in a culture die at once. C) Not all of the cells in a culture are killed. D) The pattern varies depending on the antimicrobial agent. E) The pattern varies depending on the species.

A) The cells in a population die at a constant rate.

The antimicrobial activity of chlorine is due to which of the following?A) The formation of hypochlorous acid B) The formation of hydrochloric acid C) The formation of ozone D) The formation of free O E) Disruption of the plasma membrane

A) The formation of hypochlorous acid

All of the following substances are used to preserve foods EXCEPT A) biguanides. B) nisin. C) potassium sorbate. D) sodium nitrite. E) calcium propionate.

A) biguanides.

Which concentration of ethanol is the most effective bactericide? A) 100% B) 70% C) 50% D) 40% E) 30%

B) 70% cant be too high 95-60% most effective when no growth occurs too high too low extra water helps with breaking down macromolecules into monomers

Which of the following pairs is mismatched? A) Ag - burns B) Alcohols - open wounds C) CuSO4 - algicide D) H2O2 - open wounds E) Organic acids - food preservation

B) Alcohols - open wounds

Which of the following could be used to sterilize plastic Petri plates in a plastic wrapper? A) Autoclave B) Gamma radiation C) Microwaves D) Sunlight E) Ultraviolet radiation

B) Gamma radiation

Which of the following substances is NOT an oxidizing agent? A) Chlorine B) Glutaraldehyde C) Hydrogen peroxide D) Iodine E) Ozone

B) Glutaraldehyde

Which of the following does NOT achieve sterilization? A) Dry heat B) Pasteurization C) Autoclave D) Formaldehyde E) Ethylene oxide

B) Pasteurization reduces bacterial populations in food and drink and reduces spoilage cannot effect spores, still exist

A treatment capable of inhibiting bacterial growth; does not kill.

Bacteriostatic

Which of these disinfectants acts by denaturing proteins? A) Alcohols B) Aldehydes C) Bisphenols D) Halogens E) Phenolics

C) Bisphenols phenol and phenolic compounds denature proteins Phenol: injure lipids of plasma membranes causing leakage i expensive is caustic has a punget odor lipids-nonnpolar molecule phenol- not ideal antispetic because can damage eurkaryotic cells derivatives have: phenol derivatives found in toothpaste, lysol, antispetic items

Which of the following substances is used for surgical hand scrubs?A) Phenol B) Chlorine bleach C) Chlorhexidine D) Soap E) Glutaraldehyde

C) Chlorhexidine

Which of the following substances can sterilize? A) Alcohol B) Phenolics C) Ethylene oxide D) ChlorineE) Soap

C) Ethylene oxide is effcective sterilize- remove all microbial life Some chemical agents combine with nucleic acids and/or cell proteins Aldehydes- cause cross-linking with functional groups (NH2, OH, COOH, SH) that inactives proteins and nucleic acids ex: formaldehyde Ethylene oxide: is effective but carcinogenic (potential to cause cancer) and explosive gas Chlorine dioxide: is a nontoxic and noncarcinogenic gas. it was used to decontaminate anthrax-exposed mail in 2001.

Which of the following will NOT inactivate endospores? A) Autoclave B) Chlorine dioxide C) High pressure D) Plasma E) Supercritical CO2

C) High pressure

Which of the following is the best method to sterilize heat-labile solutions? A) Dry heat B) Autoclave C) Membrane filtration D) Pasteurization E) Freezing

C) Membrane filtration

Which one of the following is most resistant to chemical biocides? A) Gram-negative bacteria B) Gram-positive bacteria C) Mycobacteria D) Protozoan cysts E) Viruses with lipid envelopes

C) Mycobacteria gram negatitive bacteria

Assume that one culture is a freshly opened package of dried yeast with 0.1% moisture, another culture is the same yeast with 7.5% moisture, and the third culture is a package of yeast mixed with water. Each culture was exposed to 130°C in a hot-air oven. Which graph in Figure 7.1 most likely shows the yeast with 0.1% moisture? A) a B) b C) c D) a and b E) b and c

C) c moist heat more effective in killing microorganisms

The preservation of beef jerky from microbial growth relies on which method of microbial control? A) filtration B) lyophilization C) desiccation D) ionizing radiation E) supercritical CO2

C) desiccation processof extreme drying

Which of the following methods is used to preserve food by slowing the metabolic processes of foodborne microbes? A) lyophilization B) nonionizing radiation C) freezing D) ionizing radiation E) pasteurization

C) freezing slows down metabolic processes, microogranisms still present but slows down growth of them

Which of the following is NOT a factor that influences the effectiveness of antimicrobial treatments? a) microbial characteristics b) number of microbes c) time of day d) presence of biofilm

C) time of day

Place the following surfactants in order from the most effective to the least effective antimicrobial activity: 1-Soap; 2-Acid-anionic detergent; 3-Quats. A) 1, 2, 3 B) 1, 3, 2 C) 2, 1, 3 D) 3, 2, 1 E) 3, 1, 2

D) 3, 2, 1

Which of the following is a limitation of the autoclave? A) Requires a long time to achieve sterilization B) Cannot inactivate viruses C) Cannot kill endospores D) Cannot be used with heat-labile materials E) Cannot be used with glassware

D) Cannot be used with heat-labile materials autoclave- use pressure, moist heat it kills all bacteria, viruses, and endospores

Which of the following does NOT directly result from application of heat? A) Breaking of hydrogen bonds B) Breaking of sulfhydryl bonds C) Denaturing of enzymes D) Cell lysis E) Damage to nucleic acids

D) Cell lysis

Which one of the following does NOT belong with the others? A) Beta-propiolactone B) Glutaraldehyde C) Ethylene oxide D) Hydrogen peroxide E) Propylene oxide

D) Hydrogen peroxide

Which of the following will NOT preserve foods? A) Desiccation B) High pressure' C) Ionizing radiation D) Microwaves E) Osmotic pressure

D) Microwaves]

Which of the following treatments is the most effective for controlling microbial growth? A) 63°C for 30 min. B) 72°C for 15 sec. C) 140°C for 4 sec. D) They are equivalent treatments. E) None is effective.

D) They are equivalent treatments.

Application of heat to living cells can result in all of the following EXCEPT A) breaking of hydrogen bonds. B) alteration of membrane permeability. C) denaturation of enzymes. D) decreased thermal death time. E) damage to nucleic acids.

D) decreased thermal death time.

Which of the following regarding antimicrobial control agents is FALSE? A) Contaminating organic debris such as blood or sputum will decrease effectiveness. B) Some agents kill by denaturing microbial cell proteins. C) Some agents affect microbial cell membranes by dissolving lipids. D) Some agents are utilized as both an antiseptic and a disinfectant. E) A true antimicrobial control agent is equally effective against both bacteria and viruses.

E) A true antimicrobial control agent is equally effective against both bacteria and viruses.

Which of the following regarding antimicrobial control agents is FALSE? A) Contaminating organic debris such as blood or sputum decrease effectiveness. B) Some agents kill by denaturing microbial cell proteins. C) Some agents affect microbial cell membranes by dissolving lipids. D) Silver is used for treating antibiotic-resistant bacteria. E) Alcohols effectively inactivate nonenveloped viruses by attacking lipids.

E) Alcohols effectively inactivate nonenveloped viruses by attacking lipids

Which of the following affects the elimination of bacteria from an object? A) Number of bacteria present B) Temperature C) pH D) Presence of organic matter E) All of the above

E) All of the above effectiveness of treatment depends on: number of microbes present, more microbes longer it will take environment- (organic matter, temperature, biolfims) where is it growing Time of exposure- how long have you been exposed? microbial characteristics- is it gram neg or gram postive both can be killed by antibiotics but the antibiotics that can be used will differ. is there a glycolyx

Which of the following is NOT a factor contributing to hospital-acquired infections? A) Some bacteria metabolize disinfectants. B) Gram-negative bacteria are often resistant to disinfectants. C) Invasive procedures can provide a portal of entry for bacteria. D) Bacteria may be present in commercial products such as mouthwash. E) All of the above may contribute to hospital-acquired infection.

E) All of the above may contribute to hospital-acquired infection.

Iodophors differ from iodine (I2) in that iodophors A) Don't stain. B) Are less irritating. C) Are longer lasting. D) Are combined with a nonionic detergent. E) All of the above.

E) All of the above.

Which of the following is NOT used to disinfect water? A) Ozone B) Gamma radiation C) Chlorine D) Copper sulfate E) Heat

E) Heat

If you were preparing nutrient agar at home and didn't have an autoclave, what could you use to sterilize the nutrient agar? A) Bleach B) Boiling for 1 hour C) Hydrogen peroxide D) Oven at 121°C for 1 hour E) Pressure cooker at 121°C for 15 minutes

E) Pressure cooker at 121°C for 15 minutes

Bone and tendons for transplant are decontaminated by A) Ethylene oxide. B) Glutaraldehyde. C) Peroxygens. D) Plasma sterilization. E) Supercritical fluids.

E) Supercritical fluids. co2 with gaseous and liquid properties used for medical implants (Pacemaker,hip replacement,)

Which one of the following pairs is mismatched? A) Ionizing radiation - hydroxyl radicals B) Ozone - takes electrons from substances C) Plasma sterilization - free radicals D) Supercritical fluids - CO2 E) Ultraviolet radiation - desiccation

E) Ultraviolet radiation - desiccation Nonionizing radiation- (UV) damages DNA by creating thymine thymine dimers errors in protein synthesis and impairment of chromosone replication occur dont completely destroy DNA create weird thymine thyime pairing that do not belong together

Disinfection of water is achieved by all of the following EXCEPT A) ozone. B) UV radiation. C) chlorine. D) copper sulfate. E) peracetic acid.

E) peracetic acid.

The removal of all microorganisms, including endospores

Sterilant sterilization; removing and destroying all microbial life everything removed sterile objects become contaminated when exposed to air and surroundings

Which of the following is used to control microbial growth in foods?a) organic acids b) alcohols c) aldehydes d) heavy metals e) all of the above

a) organic acids organic acids inhibit metabolism sarbic acid, benezoic acid, and calcium propinate prevent molds in acidic foods nitrates and nitrites prevent endospore germiniation

The absence of significant contamination is called

asepsis

Which of the following terms is mismatched? a) sterilient destroys all living organisms b) bacteriostatic- kills vegetative bacterial cells c) fungicide- kills yeast and molds d) germinicide- kills microbes virircide- inactiveates viruses

b) bacteriostatic- kills vegetative bacterial cells static- stops doesnt kill ide-death

All of the following are effective for destroying prions EXCEPT: a)NaOH+ autoclaving at 134 degrees celcius b) boiling c) proteases d) incineration e)none of these answers are correct, each of these will destroy prions

b) boiling

Which of the following is most effective for sterilizing mattresses and plastic Petri dishes? a) chlorine b) enthylene oxide c) glutaraldehyde d) autoclaving e) nonionizing radiation

b) enthylene oxide effective

Which of the following is most likely to be bactericidal? a) membrane filtration b) ionizing radiation c) lyophilization (freeze-drying) d) deep-freezing e) all of the above

b) ionizing radiation complete DNA damage

Which of the following is not a characteristic of quaternary ammonium compounds?a) bactericidal against gram-positive bacteria b) sporicidal c) amoebicidal d) fungicidal e) kills enveloped viruses

b) sporicidal

A classmate is trying to determine how a disinfectant might kill cells. You observed that when he spilled the disinfectant in your reduced litmus milk, the litmus turned blue again. You suggest to your classmate that a) the disinfectant might inhibit cell wall synthesis b) the disinfectant might oxidize molecules c) the disinfectant might denature proteins d) the disinfectant might denature proteins e) he take his work away from yours

b) the disinfectant might oxidize molecules

disenfects by disrupting plasma membrane

bisphenols

commerical sterilization is a limited heat treatment to destroy

clostridium botulium endospores

Which of the following cannot be used to sterilize a heat-labile solution stored in a plastic container? a) gamma radiation b) ethylene oxide c) supercritical fluids d) autoclaving e) short-wavelength radiation

d) autoclaving autoclaving can not be reliable for heat soulble things

Which of these disinfectants does not act by disrupting the plasma membrane? a) phenolics b) phenol c) quaternary ammonium compounds d) halogens e) biguanides

d) halogens Halogens denature enzymes and impair protein synthesis

Which of the following does not kill endospores? a) autoclaving b) incineration c) hot-air sterilization d) pasteurization e) all of the above kill endospores

d) pasteurization bacterial spores not affected by pasterization

used through scrubbing

detergents

An agent used to reduce the number of bacteria on a toliet would most accurately be called

disinfectant

Flaming is one of the simplest methods of

dry heat sterilization

Which of the following substances is used for surgical hand scrubs? a) glutaraldehyde b)chlorine bleach c)soap d) phenol e) chlorhexidine

e) chlorhexidine

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

e) heat, radiation, and some chemicals

Any process that destroys the non-spore-forming contaminants on inanimate objects is sterilization

false, it is disenfection because the endospores are still present but not active

dessication is a relible form of sterilization

false, just because there is no moisture for bacterial growth doesnt mean endospores are not present

Ultraviolent light causes irrerersible breaks in DNA strands

false, not breaks

microorganisms placed in high concentrations of salts and sugars undergo lysis

false, shrivels instead of lysis

which agents cause denaturation of enzymes and other essential proteins

heavy metals

an idophor is

iodine mixed with a surfucant

ethlyene oxide

is a sterilizing agent

To sterilize heat soluble solutions one should use

membrane filtration

which method kill microorganisms primarily by the cogulation of proteins (denaturation)

mosist heat

Which of the following is not important in maintaining the shape of proteins

peptide bonds

Which chemical agents cause a disruption of the plasma membrane and denautration of enzymes ? a) phenolics b) biguanides c) heavy metals d) halogens

phenolics

Which of the following is used on environmental surfaces, instruments, skin surfaces, and mucous membranes?

phenolics

Damage to which structure causes cellular components to leak into the surrounding medium?

plasma membrane

The time it takes to kill a microbial population is

proportional to the number of microbes

What treatment is intended to lower microbial counts on eating and drinking utensils to safe public health?

sanitization

what chemical is used to prevent molds from growing in cheese and soft drinks?

sorbic acid

The removal or destruction of ALL forms of microbial life is called

sterilization

bones and tendons transplanted by

superciritcal fluids

the lowest temperature at which all microogranisms in a particular liquid suspension could be killed in 10 minutes is called

thermal death point

Autoclaving is the most effective method of moist heat sterilization.

true

Moist heat destroys organisms by denaturing proteins.

true proteins undergo denaturation

The thermal death time is the time needed to kill all the bacteria in a particular culture at a certain temperature.

true, correct defintion

Some antimicrobial chemicals are considered to be disinfectants and antiseptics.

true, there can be different functions