How does a chemostat maintain a constant population size?

Lyophilization can be described as ________.

a. freeze-drying

b. deep-freezing

c. refrigeration

d. pickling

A toxic form of oxygen,___________ oxygen, is molecular oxygen with electrons that have been boosted to a higher energy state.

The most reactive of the four toxic forms of oxygen is ________.

a. the hydroxyl radical

b. the peroxide anion

c. the superoxide radical

d. singlet oxygen

Why must media, vessels, and instruments be sterilized before they are used for microbiological procedures?

Which of the following types of radiation is more widely used as an antimicrobial technique?

a. electron beams

b, visible light waves

c. radio waves

d. microwaves

In practical terms in everyday use, which of the following statements provides the definition of sterilization?

a. Sterilization eliminates all organisms and viruses.

b. Sterilization eliminates harmful microorganisms and viruses.

c. Sterilization eliminates prions.

d. Sterilization eliminates hyperthermophiles.

Describe three types of microbes that are extremely resistant to antimicrobial treatment, and explain why they are resistant.

Compare and contrast the action of alcohols, halogens, and oxidizing agents in controlling microbial growth.

Which of the following substances would most effectively inhibit anaerobes?

a. phenol

b. silver

c. ethanol

d. hydrogen peroxide

Hyperthermophilic prokaryotes may remain viable in canned goods after commercial sterilization. Why is this situation not dangerous to consumers?

Which of the following adjectives best describes a surgical procedure that is free of microbial contaminants?

a. disinfected

b. sanitized

c. degermed

d. aseptic

Why are alcohols more effective in a 70% solution than in a 100% solution?

Biosafety Level 3 includes __________ .

a. double sets of entry doors

b. pressurized suits

c. showers in entryways

d. all of the above

Contrast the structures and actions of soaps and quats.

A sample of E. coli has been subjected to heat for a specified time, and 90% of the cells have been destroyed. Which of the following terms best describes this event?

a. thermal death point

b. thermal death time

c. decimal reduction time

d. none of the above

What are some advantages and disadvantages of using ionizing radiation to sterilize food?

Which of the following substances is least toxic to humans?

a. carbolic acid

b. glutaraldehyde

c. hydrogen peroxide

d. formalin

How can campers effectively treat stream water to remove pathogenic protozoa, bacteria, and viruses?

Which of the following chemicals is active against bacterial endospores?

a. copper ions

b. ethylene oxide

c. ethanol

d. triclosan

Which of the following disinfectants acts against cell membranes?

a. phenol

b. peracetic acid

c. silver nitrate

d. glutaraldehyde

Which of the following disinfectants contains alcohol?

a. iodophor

b. quat

c. formalin

d. tincture of bromine

Which antimicrobial chemical has been used to sterilize spacecraft?

a. phenol

b. alcohol

c. heavy metal

d. ethylene oxide

Which class of surfactant is most soluble in water?

a. quaternary ammonium compounds

b. alcohols

c. soaps

d. peracetic acids

Which of the following substances or processes kills microorganisms on laboratory surfaces?

a. antiseptics

b. disinfectants

c. degermers

d. pasteurization

Compare and contrast four tests that have been developed to measure the effectiveness of disinfectants.

Which of the following terms best describes the disinfecting of cafeteria plates?

a. pasteurization

b. antisepsis

c. sterilization

d. sanitization

Why is it necessary to use strong disinfectants in areas exposed to tuberculosis patients?

The microbial death rate is used to measure the effectiveness of            .

a. a detergent

b. an antiseptic

c. sanitization techniques

d. all of the above

Why do warm disinfectant chemicals generally work better than cool ones?