Micro Quiz ch. 7

If the DRT of a microbial population is 3 min., how long would it take to completely eliminate a microbial population of 10^7 cells? Select one: a. 21 min. b. 10,000,000 (10^7) min. c. 3 min. d. 24 min. e. 18 min.

24 min.

If the DRT of a microbial population is 5 min., how long would it take to completely eliminate a microbial population of 10^5 cells? Select one: a. 15 min. b. 30 min. c. More information is needed d. 100,000 (10^5) min. e. 5 min.

30 min.

Which of the following regarding antimicrobial control agents is FALSE? Select one: a. Silver-impregnated dressings are used for treating antibiotic-resistant bacteria. b. Some agents affect microbial cell membranes by dissolving lipids. c. Alcohols effectively inactivate nonenveloped viruses by attacking lipids. d. Contaminating organic debris such as blood or sputum decrease effectiveness. e. Some agents kill by denaturing microbial cell proteins.

Alcohols effectively inactivate nonenveloped viruses by attacking lipids.

A chemical used on human tissue to reduce the number of microbes before inserting an IV would be called a/an Select one: a. Sanitizer b. Antiseptic c. Commercial sterilizer d. Disinfectant e. Sterilizing agent

Antiseptic

In a use-dilution test, an antimicrobial chemical is tested Select one: a. Against MRSA b. At concentrated strength c. At the concentration it will be used at d. Against Pseudomonas only e. Diluted 50:50

At the concentration it will be used at

Endospores are destroyed by which of these methods? Select one: a. Lyophilization b. Boiling for 10 minutes. c. Autoclaving. d. Pasteurization. e. Endospores are indestructible.

Autoclaving.

Which of the following shows the maximum resistance to physical and chemical agents? Select one: a. Protozoal cysts b. Bacterial spores c. Viruses d. Fungal spores e. Gram negative bacteria

Bacterial spores

Which of the following substances is used for surgical hand scrubs? Select one: a. Soap b. Phenol c. Biguanides d. Glutaraldehyde e. Chlorine bleach

Biguanides

All of the following are effective for destroying prions EXCEPT Select one: a. NaOH + autoclaving at 134°C. b. Boiling. c. Proteases. d. None of the answers are correct; each of these will destroy prions. e. Incineration.

Boiling.

Which of the following could be used to sterilize plastic Petri plates in a plastic wrapper? Select one: a. Ultraviolet radiation b. Gamma radiation c. Sunlight d. Microwaves e. Autoclave

Gamma radiation

Pasteurization Select one: a. Reduces microbes to safe public health levels b. Sterilizes milk c. Kills endospores d. Sterilizes juice e. Kills all bacteria

Reduces microbes to safe public health levels

Which concentration of ethanol is the most effective bactericide? Select one: a. Fifty percent b. Thirty percent c. Forty percent d. Seventy percent e. One hundred percent

Seventy percent

Contaminated hospital equipment represents a difficult environment to control harmful microbial growth. Which of the following represents an accurate statement? Select one: a. The cell walls of gram-negative bacteria are especially resistant to many chemicals that are used to destroy microbes. b. The presence of organic matter such as dried blood or protein will not affect the action of antimicrobial agents. c. Antimicrobial agents are equally effective at all temperatures. d. Biofilms, often found contaminating hospital equipment, are relatively simple targets for biocides to reach effectively e. Sanitization in the hospital is more important than sterilization.

The cell walls of gram-negative bacteria are especially resistant to many chemicals that are used to destroy microbes.

Which of the following best describes the pattern of microbial death? Select one: a. The cells in a population die at a constant rate. b. The pattern varies depending on the antimicrobial agent. c. Not all of the cells in a culture are killed. d. All the cells in a culture die at once. e. The pattern varies depending on the species.

The cells in a population die at a constant rate.

In a disc diffusion test to evaluate the effectiveness of an antimicrobial chemical, the lack of a zone of inhibition indicates Select one: a. The chemical is toxic b. The microbe is resistant to the chemical c. The chemical is inert d. The microbe is sensitive to the chemical e. The microbe has metabolized the chemical

The microbe is resistant to the chemical

The lowest temperature at which all microbes are killed within 10 min. time is the Select one: a. Microbe kill time b. Decimal reduction time c. Microbe kill temp d. Thermal death time e. Thermal death point

Thermal death point

All of the following are true concerning emerging infectious diseases EXCEPT Select one: a. Known pathogens develop evolutionary changes. b. They always involve sporadic cases in endemic areas. c. They include newly described infectious agents. d. They result from human exposure to a pathogen due to ecological changes. e. Known diseases spread to new regions or populations.

They always involve sporadic cases in endemic areas.

Heavy metals show oligodynamic action. This means Select one: a. They are effective against endospores b. They are irritating. c. They are toxic. d. They are active in small amounts. e. They are good sterilizing agents.

They are active in small amounts.

The microbial death rate is influenced by all the following factors EXCEPT Select one: a. Time of exposure b. Microbial characteristics c. Toxins produced by the microbes d. Concentration of microbial control agent e. Number of microbes

Toxins produced by the microbes

Dry heat sterilization protocols require higher temperatures for longer periods of time than moist heat sterilization protocols. Select one: a. True b. False

True

Which of the following is suitable for use on tissues for microbial control to prevent infection? Select one: a. disinfectant b. water c. antiseptic d. commercializer sterilizer e. sterilant

antiseptic

Which of the following is an approved sterilant? Select one: a. ethanol b. chlorhexidine c. bleach d. phenol e. ethylene oxide

ethylene oxide

Which of the following microbial control methods does not actually kill microbes or inhibit their growth but instead removes them physically from samples? Select one: a. desiccation b. chemiclaves c. filtration d. lyophilization e. non-ionizing radiation

filtration

Which of the following best describes a microbial control protocol that inhibits the growth of molds and yeast? Select one: a. fungistatic b. bacteriostatic c. fungicide d. virucide e. tuberculocidal

fungistatic

Which of the following best describes a microbial control protocol that inhibits the growth of molds and yeast? Select one: a. virucide b. bacteriostatic c. tuberculocidal d. fungicide e. fungistatic

fungistatic

Bleach is an example of what group of chemicals used for disinfection? Select one: a. biguanides b. alcohols c. halogens d. QUATS e. heavy metals

halogens

Bleach is an example of what group of chemicals used for disinfection? Select one: a. halogens b. heavy metals c. alcohols d. biguanides e. QUATS

halogens

Which of the following types of medical items require sterilization? Select one: a. scale for weighing patients b. bed linens c. blood pressure cuffs d. needles e. stethoscopes

needles

Which of the following compounds is NOT an enzyme? Select one: a. Coenzyme A b. Dehydrogenase c. Cellulase d. Sucrase e. Collagenase

Coenzyme A

Which of the following would not affect the germicidal activity of a chemical? Select one: a. Presence or absence of organic matter b. Strength of the chemical c. Length of time of exposure d. Degree of microbial contamination e. Cost of the chemical

Cost of the chemical

An agent used to reduce the number of bacteria on a toilet would most accurately be called a(n) Select one: a. Disinfectant. b. Fungicide. c. Aseptic. d. Antiseptic. e. Virucide.

Disinfectant.

The best choice to sterilize a lipid-based substance would be Select one: a. Halogens b. Dry heat c. An autoclave d. Biguanides e. Alcohols

Dry heat

Why is boiling an ineffective means of sterilizing microbial media? Select one: a. Thermophiles can withstand boiling temperatures. b. Nutrients in the medium are destroyed by boiling. c. Culture medium is destroyed by boiling. d. Endospores can survive many hours of boiling. e. Many microbes multiply at boiling temperatures.

Endospores can survive many hours of boiling.

Which lists in decreasing order, from most resistant to least resistant? Select one: a. Gram-positive bacteria, fungi, mycobacteria, prions, gram negative bacteria b. Lipophilic viruses, gram positive bacteria, mycobacteria, gram-negative bacteria c. Endospores, mycobacteria, protozoal cysts, gram-negative bacteria, gram positive bacteria, lipophilic viruses d. Gram-negative bacteria, lipophilic viruses, protozoal cysts, mycobacteria, endospores e. Fungi, gram-positive bacteria, endospores, mycobacteria, gram-negative bacteria

Endospores, mycobacteria, protozoal cysts, gram-negative bacteria, gram positive bacteria, lipophilic viruses

Which of the following chemical agents is used for sterilization? Select one: a. Ethylene oxide b. Alcohol c. Chlorine d. Phenolics e. Soap

Ethylene oxide

The process of pasteurization to reduce food spoilage utilizes high heat to kill all bacteria present. Select one: a. TRUE b. FALSE

FALSE

Antiseptics and disinfectants are used to sterilize surfaces. Select one: a. False b. True

False

In the disc diffusion assays , the absence of a zone of inhibition around a disc to which a chemical disinfectant has been applied indicates sensitivity of the microbe to the disinfectant. Select one: a. True b. False

False

Sanitization leaves an object free of microbes. Select one: a. True b. False

False

Which of the following is the correct parameter for autoclaving? Select one: a. Fifteen minutes at 121°C and 15 psi b. Thirty minutes at 115°C and 10 psi c. Fifteen minutes at 115°C and 10 psi d. Thirty minutes at 100°C and 0 psi e. Fifteen minutes at 100°C and 0 psi

Fifteen minutes at 121°C and 15 psi

Which of the following methods is used to preserve food by slowing the metabolic processes of foodborne microbes? Select one: a. Nonionizing radiation b. Ionizing radiation c. Pasteurization d. Lyophilization e. Freezing

Freezing

Salting works to effectively decrease microbial growth in food by creating a(n) _____ environment. Select one: a. Hypotonic b. Isotonic c. Alkaline d. Hypertonic e. Acidic

Hypertonic

Halogens used for microbial control include Select one: a. Ethanol and isopropyl alcohol b. Iodine and Chlorine c. Silver and copper d. Hydrogen peroxide and peracetic acid e. Formaldehyde and glutaraldehyde

Iodine and Chlorine

Ethylene oxide Select one: a. Requires high heat to be effective. b. Is the active chemical in household bleach. c. Is a sterilizing agent. d. Is a good antiseptic. e. Is not sporicidal.

Is a sterilizing agent.

Which of the following is a limitation of the autoclave? Select one: a. It cannot inactivate viruses. b. It cannot be used with heat-labile materials. c. It cannot kill endospores. d. It requires an excessively long time to achieve sterilization. e. It cannot be used with glassware.

It cannot be used with heat-labile materials.

Which of the following is the best method to sterilize heat-labile solutions? Select one: a. Dry heat b. Pasteurization c. Autoclave d. Membrane filtration e. Freezing

Membrane filtration

Which of the following does NOT achieve sterilization? Select one: a. Ethylene oxide b. Dry heat c. Autoclave d. Pasteurization e. Supercritical fluids

Pasteurization

All of the following are sterilizers except Select one: a. Hydrogen peroxide b. Phenolics c. Supercritical fluids d. Autoclave e. Ethylene oxide

Phenolics

If you were preparing nutrient agar at home and did not have an autoclave, what could you use to sterilize the nutrient agar? Select one: a. Bleach b. Pressure cooker at 121°C for 15 minutes c. Boiling for one hour d. Oven at 121°C for one hour e. Hydrogen peroxide

Pressure cooker at 121°C for 15 minutes

Chemicals that are non-toxic and a good choice for preserving cosmetics are Select one: a. QUATS b. biguanides c. phenolics d. aldehydes e. heavy metals

QUATS

Which of the following is a disinfectant that acts by disrupting the plasma membrane? Select one: a. QUATS b. Heavy metals c. Aldehydes d. Organic acids e. Halogens

QUATS

The decimal reduction time refers to the amount of time it takes to which of the following? Select one: a. reduce a microbial population by 0.1% b. completely eliminate the population c. reduce a microbial population by 90% d. reduce a microbial population by 10% e. maintain a population in stationary phase

reduce a microbial population by 90%

Microbial death is defined as Select one: a. the inability of a microbe to use oxygen b. the inability of a microbe to undergo mitosis c. the permanent loss of reproductive capability in microorganisms d. the inability of a microbe to undergo conjugation e. the inability of a microbe to form endospores

the permanent loss of reproductive capability in microorganisms