Microbio – Chapter 5

Which of the following is/are transferred to daughter cells during cell division?
A) genomic DNA, the blueprint for everything the cell needs
B) individual genes and enzymes to later be brought together to form the genome
C) chromosome and enzymes to immediately begin cellular metabolism
D) chromosome, proteins, and all other cellular constituents
chromosome, proteins, and all other cellular constituents
Which is most abundant and active in divisome complexes?
A) FtsZ
B) DNA replication forks
C) MinCD
D) MreB
MreB
The process by which two cells arise from one is known as
A) conjugation.
B) binary fission.
C) meiosis.
D) mitosis.
binary fission.
A bacterium that lacks the mreB gene will have a ________ shape.
A) bacillus
B) coccoid
C) short bacillus
D) vibrio
coccoid
The time interval required for the formation of two cells from one is called the
A) generation time.
B) growth time.
C) growth rate.
D) division rate.
generation time.
Enumerating cells in a biofilm is especially challenging for
A) microscopic direct counting.
B) measuring turbidity.
C) viability counts with spread plating.
D) microscopic direct county, measuring turbidity, and viability counts with spread plating.
microscopic direct county, measuring turbidity, and viability counts with spread plating.
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The time between inoculation and the beginning of growth is usually called the
A) lag phase.
B) log phase.
C) dormant phase.
D) death phase.
lag phase.
Optical density and viable cell concentration are LEAST proportional to each other during
A) lag phase.
B) exponential growth phase.
C) stationary phase.
D) death phase.
death phase.
To determine viable cell counts of a heat-sensitive bacterial isolate, which cell counting method would be best to AVOID?
A) spread-plate method
B) pour-plate method
C) live staining and direct counting with a microscope
D) both spread- and pour-plate methods
pour-plate method
Bacteria that are able to grow in humans and cause disease have likely evolved to be
A) psychrophiles.
B) mesophiles.
C) thermophiles.
D) hyperthermophiles.
mesophiles.
Where would it be best to isolate bacteria from to study the mechanism of the sodium motive force?
A) human gut
B) hot springs
C) soda lakes
D) volcanoes
soda lakes
An agar plate for counting colonies and maximizing statistical validity should ideally contain
A) 1 to 100 colonies.
B) 50 to 100 colonies.
C) 30 to 300 colonies.
D) 100 to 1000 colonies.
30 to 300 colonies.
Relative to enzymes in mesophilic microorganisms, which of the following is NOT characteristic of enzymes in psychrophiles?
A) decreased alpha helices
B) decreased beta sheets
C) less hydrogen bonds
D) less ionic bonds
less ionic bonds
The number of colonies obtained in a plate count does NOT depend on the
A) inoculum volume.
B) size of the colonies.
C) type of culture medium.
D) incubation time.
size of the colonies.
Cell density in a chemostat is controlled by
A) the concentration of the limiting nutrient.
B) the dilution factor.
C) the size of the initial inoculum.
D) the concentration of the limiting nutrient, the dilution factor, and the size of the initial inoculum.
the concentration of the limiting nutrient.
Many aromatic compounds used for growth substrates by bacteria are broken down during high heat autoclaving. Which is the BEST way to sterilize these aqueous solutions?
A) ethylene oxide gas treatment
B) gamma irradiation
C) 0.2 μm filter sterilization
D) ultraviolet radiation
0.2 μm filter sterilization
What temperature is most commonly used for autoclaves to sterilize growth media and other devices prior to experimentation?
A) 95°C
B) 101°C
C) 121°C
D) 140°C
121°C
The MOST effective antibiotics in preventing growth of disease-causing bacteria are
A) bacteriocidal.
B) bacteriostatic.
C) bacteriolytic.
D) bacteriolytic or bacteriocidal.
bacteriolytic or bacteriocidal.
Most mesophilic organisms can grow in a temperature range of
A) 0-15°C.
B) 10-20°C.
C) 20-40°C.
D) 50-65°C.
20-40°C.
The addition of thioglycylate into a growth medium would NOT support the growth of a(n)
A) aerotolerant anaerobe.
B) facultative aerobe.
C) microaerophilic aerobe.
D) obligate anaerobe.
microaerophilic aerobe.
A microbe growing in a refrigerator is likely
A) psychrophilic.
B) mesophilic.
C) psychrotolerant or psychrophilic.
D) hyperthermophilic.
psychrotolerant or psychrophilic.
Consider solution A (pH 6) and solution B (pH 9). Which of the following statements is CORRECT?
A) Solution A is 3 times more acidic than solution B.
B) Solution A is 300 times more acidic than solution B.
C) Solution B is 1,000 times more alkaline (basic) than solution A.
D) Solution B is 3,000 times more alkaline (basic) than solution A.
Solution B is 1,000 times more alkaline (basic) than solution A.
An antibiotic that increased the activity of ________ would likely result in cell death.
A) autolysin
B) binary fission
C) stationary growth
D) ionic bonds in proteins
autolysin
Which of these statements is/are TRUE?
A) In general, prokaryotic organisms can grow at higher temperatures than eukaryotic organisms.
B) The most thermophilic prokaryotes are species of Archaea.
C) Nonphototrophic organisms are able to grow at higher temperatures than phototrophic organisms.
D) All of the statements are true.
All of the statements are true.
A chemical that denatures proteins is MOST likely to be classified as a(n) ________ agent.
A) antiseptic
B) bacteriostatic
C) bacteriocidal
D) detergent
bacteriocidal
The ratio of the vapor pressure of the air in equilibrium with a substance to the vapor pressure of pure water is known as
A) water activity.
B) vapor activity.
C) positive water balance.
D) osmosis.
water activity.
Organisms able to live in environments with high sugar concentrations are
A) halotolerant.
B) osmophiles.
C) xerophiles.
D) anaerobic fermenting bacteria.
osmophiles.
When water activity is low, an organism must
A) increase its internal solute concentration.
B) increase its external solute concentration.
C) decrease its internal solute concentration.
D) decrease its external solute concentration.
increase its internal solute concentration.
A bacterium containing ________ provided with hydrogen peroxide will produce oxygen bubbles.
A) catalase
B) superoxide dismutase
C) superoxide reductase
D) peroxidase
catalase
A halotolerant facultative anaerobic bacterium would grow BEST in a ________ environment.
A) oxygen depleted saline
B) oxygenated saline
C) oxygen depleted non-saline
D) oxygenated non-saline
oxygenated non-saline
Which of the following forms of oxygen is/are generally toxic to living organisms?
A) superoxide anion
B) hydrogen peroxide
C) hydroxyl radical
D) superoxide, hydrogen peroxide, and hydroxyl radicals are all toxic
superoxide, hydrogen peroxide, and hydroxyl radicals are all toxic
Superoxide dismutase and catalase work together to convert superoxide into
A) peroxide.
B) oxygen.
C) ozone.
D) water.
oxygen.
Which of the following methods to enumerate cells often requires specialized staining to observe non-pigmented bacteria?
A) spectrophotometry/turbidity
B) spread-plating
C) microscopy
D) spread-plating, turbidity, and microscopy
microscopy
To determine the specific growth rate of a bacterial population, it is essential to know
A) cell concentrations at varied time points.
B) total number of cells in the population at varied time points.
C) cell concentrations at varied time points or the generation time.
D) turbidity measurements and the total number of cells in the population at varied time points.
cell concentrations at varied time points.
The partition that is a result of the inward growth of the cytoplasmic membrane and cell wall from opposing directions is known as the
A) divisome.
B) septum.
C) autolysin.
D) colony.
septum.
Which term is most relevant in describing the efficacy of an antimicrobial for use in a clinical setting?
A) effective dose
B) sterilization coefficient
C) lethal dosage
D) minimum inhibitory concentration
minimum inhibitory concentration
In general, which group is MOST resistant to radiation?
A) microscopic fungi
B) viruses
C) thermotolerant bacteria
D) spore-forming bacteria
viruses
What is the function of bactoprenol?
A) It is a hydrophobic alcohol that transports peptidoglycan precursors across the cytoplasmic membrane.
B) It is responsible for forming the peptide cross-links between muramic acid residues in adjacent glycan chains.
C) It triggers the recruitment of FtsZ and the initiation of the divisome.
D) It supplies the energy necessary for transpeptidation to occur.
It is a hydrophobic alcohol that transports peptidoglycan precursors across the cytoplasmic membrane.
Which method would be LEAST effective at sterilizing a glass hockey stick to use in the spread-plate method?
A) autoclaving
B) gamma radiation
C) ethanol soaking
D) ultrahigh-temperature pasteurization
ultrahigh-temperature pasteurization
By controlling the concentration of nutrients added into a chemostat continuously, cells can constantly be maintained at
A) exponential growth phase.
B) stationary growth phase.
C) log or stationary growth phase.
D) death growth phase.
log or stationary growth phase.
One laboratory group repeated the same experiment described by others with the identical bacterial isolate and the same growth medium and conditions used but were unable to achieve the same O.D. at 600 nm. What is the LEAST likely cause for this discrepancy of turbidity measured?
A) One lab used 16 mm wide test tubes and the other used 18 mm wide test tubes.
B) One lab subtracted the yellow color of the growth medium away from the final turbidity reported whereas the other lab used colorless water.
C) One lab vigorously dispersed the biofilm-forming bacteria with vortexing and the other did not.
D) The two labs varied with 1000 m elevation and did not consider the influence of pressure.
The two labs varied with 1000 m elevation and did not consider the influence of pressure.
A drug targeting ________ would NOT be an effective antibiotic.
A) ZipA
B) FtsI
C) MreB
D) transpeptidation
MreB
An antiseptic (or germicide) is distinguished from other sterilizing compounds by
A) being able to inhibit growth of microorganisms but not necessarily kill all of them.
B) being able to be used on living tissues without harm.
C) its ability to protect from subsequent microbial infections—not just initial sterilization.
D) killing all bacteria and microscopic fungi but not being effective against viruses.
being able to be used on living tissues without harm.
Growing bacteria that degrade an environmental pollutant, which is also toxic to the cells at artificially high concentrations, might require ________ to obtain a sufficient population for biochemistry studies.
A) a continuous batch culture
B) a second growth substrate to keep the culture in exponential growth phase
C) steady state growth kinetics
D) the use of a chemostat
the use of a chemostat