Chapter 5

Dry heat takes a much shorter time to sterilize material than wet heat. A. True B. False

False

Heat treatment is an effective method for sterilization or disinfection of all materials. A. True B. False

False

Hydrogen peroxide may be used as a sterilant on living tissue. A. True B. False

False

Prions are easily destroyed by common sterilization procedures. A. True B. False

False

The endospores of Pseudomonas make that organism very difficult to kill. A. True B. False

False

Moist heat kills microorganisms by A. irreversible denaturation of proteins. B. denaturation of nucleic acids. C. dissolving the capsule. D. destruction of carbohydrates in the cell wall.

Irreversible denaturation of proteins.

Glutaraldehyde A. does not affect non-enveloped viruses. B. attacks lipids. C. is very good for use on heat-sensitive medical items. D. is, if given enough time, able to destroy all forms of microbial life AND is very good for use on heat-sensitive medical items. E. is, if given enough time, able to destroy all forms of microbial life.

Is, if given enough time, able to destroy all forms of microbial life AND is very good for use on heat-sensitive medical items.

Which of the following is true of hydrogen peroxide? A. It is a sterilant for inanimate objects and is quickly inactivated on living tissue; it is broken down by catalase into water and oxygen; AND it is even more effective when used in combination with peracetic acid. B. It is even more effective when used in combination with peracetic acid. C. It leaves a toxic residue. D. It is broken down by catalase into water and oxygen. E. It is a sterilant for inanimate objects and is quickly inactivated on living tissue.

It is a sterilant for inanimate objects and is quickly inactivated on living tissue; it is broken down by catalase into water and oxygen; AND it is even more effective when used in combination with peracetic acid.

Liquid media containing heat-sensitive components would best be sterilized by A. freezing. B. ultraviolet (UV) light at 500 nm. C. membrane filtration. D. lyophilization.

Membrane filtration.

Lister developed his ideas on prevention of infection during medical procedures after studying the work of A. Pasteur. B. Jenner. C. Koch. D. Fleming.

Pasteur.

Which of the following is not a sterilization method? A. Filtration B. Pasteurization C. Autoclave D. Hot air oven

Pasteurization

A common environmental organism that may even grow in certain chemical disinfectants is A. Streptococcus pneumoniae. B. enveloped virus. C. Escherichia coli. D. Pseudomonas aeruginosa.

Pseudomonas aeruginosa.

Which would be most effective against Pseudomonas? A. Iodophors B. Quaternary ammonium compounds C. Radiation D. Alcohol

Radiation

Chlorine A. is ineffective when diluted. B. readily reacts with organics to produce potentially carcinogenic trihalomethanes. C. is an effective, inexpensive, disinfectant able to destroy all types of microorganisms. D. is unaffected by the presence of organic material. E. readily reacts with organics to produce potentially carcinogenic trihalomethanes AND is an effective, inexpensive, disinfectant able to destroy all types of microorganisms.

Readily reacts with organics to produce potentially carcinogenic trihalomethanes AND is an effective, inexpensive, disinfectant able to destroy all types of microorganisms.

Hexachlorophene has been particularly effective against A. Enterobacter aerogenes. B. Micrococcus aureus. C. Escherichia coli. D. Staphylococcus aureus.

Staphylococcus aureus.

The process of killing or removing all of the microorganisms in or on a material is termed A. sterilization. B. antisepsis. C. disinfection. D. sanitation.

Sterilization.

Microwaves do not kill organisms directly but kill by A. the heat they generate in a product. B. creating thymine dimers. C. generating free radicals. D. generating toxins.

The heat they generate in a product.

Compounds of tin, mercury, arsenic, and copper are no longer used to prevent microbial growth in cooling water primarily because A. antibiotics are cheaper. B. other chemicals were shown to be much more effective. C. microbes developed resistance to these metals. D. their use contributes to serious pollution of natural waters. E. All of the choices are correct.

Their use contributes to serious pollution of natural waters.

Generally, heavy metals, except silver, have been proven to be too toxic for use on human tissue and are no longer used medically. A. True B. False

True

Organic acids, such as benzoic acid, are often added to foods to prevent microbial growth. A. True B. False

True

Upon heat treatment, bacteria die at a constant proportion. A. True B. False

True

Which of the following methods sterilize the materials? A. Pasteurization B. High-temperature-short-time pasteurization (HTST) C. Ultrahigh-temperature (UHT) method D. None of these are sterilization methods.

Ultrahigh-temperature (UHT) method

Plain soap is very effective in controlling spread of microorganisms because it is A. bacteriostatic. B. bactericidal. C. virucidal. D. very effective at the mechanical removal of microorganisms.

Very effective at the mechanical removal of microorganisms

Which of the following is(are) considered when selecting a germicidal chemical? A. Toxicity B. Cost C. Compatibility with the material being treated D. Environmental impact E. All of the choices are correct.

All of the choices are correct

Chemical germicides A. may react irreversibly with proteins/enzymes. B. may react with cytoplasmic membranes or viral envelopes. C. may be disinfecting or even sterilizing. D. are sensitive to dilution factor, time of contact, and temperature of use. E. All of the choices are true.

All of the choices are true

One of the first chemicals used by Lister to prevent surgical infections was A. alcohol. B. mercury. C. iodine. D. carbolic acid.

Carbolic acid

Quaternary ammonium compounds are A. very effective against Pseudomonas. B. attracted to the negative charge on the microbial cell surface. C. cationic detergents that help wash surfaces. D. used as a 37% aqueous solution. E. cationic detergents that help wash surfaces AND attracted to the negative charge on the microbial cell surface.

Cationic detergents that help wash surfaces AND attracted to the negative charge on the microbial cell surface.

Ultraviolet radiation at the bactericidal wavelength destroy bacteria by A. denaturing proteins. B. destroying endospores. C. damaging nucleic acid. D. preventing spore formation.

Damaging nucleic acid.

Upon treatment with heat or chemicals, bacteria will A. die at a constant proportion. B. all die immediately. C. die at a geometric rate. D. die at an exponential rate.

Die at a constant proportion.

Which are essentially equivalent treatments? A. Dry 121°C heat for 1.5 hours; wet 200°C heat for 15 minutes B. Dry 200°C heat for 1.5 hours; wet 121°C heat for 15 minutes C. Dry 100°C heat for 2.0 hours; wet 100°C heat for 30 minutes D. Dry 160°C heat for 1.0 hour; wet 200°C heat for 30 minutes

Dry 200°C heat for 1.5 hours; wet 121°C heat for 15 minutes