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WorksheetsBSCi106 Quiz No. 3
Total questions: 22
Worksheet time: 26mins
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
EMB agar is a medium used in the identification and isolation of pathogenic bacteria. It contains digested meat proteins as a source of organic nutrients. Two indicator dyes, eosin and methylene blue, inhibit the growth of gram-positive bacteria and distinguish between lactose fermenting and nonlactose fermenting organisms. Lactose fermenters form metallic green or deep purple colonies, whereas the nonlactose fermenters form completely colorless colonies. EMB agar is an example of which of the following?
a selective medium only
a differential medium only
a selective medium and a chemically defined medium
a selective medium, a differential medium, and a complex medium
A laboratory technician uses a MacConkey agar that is designed to suppress the growth of Gram-positive bacteria, and encourage the growth of Gram-negative microbes. MacConkey agar is a type of _____
differential media
nutrient agar
selective media
nutritive media
complex media
Period of equilibrium in which new cell numbers are balanced by the death of cells is considered the ____
growth phase.
equilibrium phase
log phase.
stationary phase.
Which growth phase includes an exponential growth due to the reproduction by binary fission (bacteria) or mitosis (yeast).
lag phase
stationary phase
log phase
prolonged death phase
In binary fission, all of the following occur EXCEPT
there is an increase in numbers.
the bacteria cell invades a host cell.
the resulting cells are genetically identical.
only one parent cell was involved at the beginning.
A plasmid that contains multiple genes for drug resistance is known as a
Resistance factor
Fertility factor
Acquired resistance
Intrinsic resistance
Superbugs
This refers to microbes (mainly bacteria) that have become resistant to one or more antimicrobial agents.
Resistance factor
Fertility factor
Acquired resistance
Intrinsic resistance
Superbugs
Ampicillin belongs to what type of antibiotics
narrow spectrum
broad spectrum
multi-resistant
all of the above
This refers to the use of chemical agents to inhibit the growth of pathogens, either temporarily or permanently.
chemical disinfection
physical disinfection
microbial disinfection
none of the above
This is used in hospitals and medical and dental clinics to clean equipment.
Desiccation
Radiation
Ultrasonic waves
Gaseous atmosphere
This results in dried microorganisms that remain viable, but cannot reproduce
Desiccation
Radiation
Ultrasonic waves
Gaseous atmosphere
Discuss different reasons why antimicrobial agents should not be used indiscriminately. (5pts.)
