BSCi106 Quiz No. 3

Bacteria isolated from a hot tub at 39 °C are probably which of the following?

• thermophiles

• psychrotrophs

• mesophiles

• basophiles

• hyperthermophiles

Which of the following is the reason jams and dried meats often do not require refrigeration to prevent spoilage?

• low pH

• toxic alkaline chemicals

• naturally occurring antibiotics

• low water activity

• high pH

A soup container was forgotten in the refrigerator and shows contamination. The contaminants are probably which of the following?

•  thermophiles

•  acidophiles

• mesophiles

• psychrotrophs

• basophiles

 In which environment are you most likely to encounter an acidophile?

• human blood at pH 7.2

• a hot vent at pH 1.5

• human intestine at pH 8.5

• milk at pH 6.5         

Pseudomonas aeruginosa is a common pathogen that infects the airways of patients with cystic fibrosis. It does not grow in the absence of oxygen. The bacterium is probably which of the following?

• an aerotolerant anaerobe

• an obligate aerobe

• an obligate anaerobe

• a facultative anaerobe

Which of the following is suitable for use on tissues for microbial control to prevent infection?

• disinfectant

• antiseptic

• sterilant

•  water

Which of the following best describes a microbial control protocol that inhibits the growth of molds and yeast?

• bacteriostatic

• fungicidal

• bactericidal

• fungistatic

Autoclaving pressure is usually set at

• 15 psi at 121°C

• 15 psi at 122°C

• 15 psi at 123°C

• 15 psi at 124°C

• 15 psi at 125°C

A microbicidal agent has what effect?

• sterilizes

• inhibits microorganisms

• is toxic to human cells

• destroys microorganisms

Which of the following is the best definition of generation time in a bacterium?

• the length of time it takes to reach the log phase

• the length of time it takes for a population of cells to double

• the time it takes to reach stationary phase

• the length of time of the exponential phase