TEST BANK CHAP 5 - Details

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74 questions

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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

D) 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

D) MreB

The process by which two cells arise from one is known as A) conjugation. B) binary fission. C) meiosis. D) mitosis.

B) binary fission.

A bacterium that lacks the mreB gene will have a ________ shape. A) bacillus B) coccoid C) short bacillus D) vibrio

B) 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.

A) 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.

D) microscopic direct county, measuring turbidity, and viability counts with spread plating.

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.

A) 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.

D) 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

B) 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.

B) 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

C) 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.

C) 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

D) 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.

B) 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.

A) 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

C) 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

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.

D) 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.

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.

C) microaerophilic aerobe.

A microbe growing in a refrigerator is likely A) psychrophilic. B) mesophilic. C) psychrotolerant or psychrophilic. D) hyperthermophilic.

C) 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.

C) 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

A) 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.

D) 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

C) 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.

A) water activity.

Organisms able to live in environments with high sugar concentrations are A) halotolerant. B) osmophiles. C) xerophiles. D) anaerobic fermenting bacteria.

B) 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.

A) 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

A) 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

D) 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

D) 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.

B) 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

C) 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.

A) 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.

B) 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

D) minimum inhibitory concentration

In general, which group is MOST resistant to radiation? A) microscopic fungi B) viruses C) thermotolerant bacteria D) spore-forming bacteria

B) 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.

A) 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

D) 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.

C) 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.

D) 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

C) 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.

B) 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

D) the use of a chemostat

Microbial growth is generally described as the increased number of cells rather than the expanding size of an individual microbial cell.

TRUE

Generation of new bacillus-shaped cells starts with one cell elongating and terminates when split into two separate bacilli.

TRUE

The activity of MinC and MinD direct whether a bacterial cell will be coccoid or bacillus shaped

FALSE

In fast-growing Escherichia coli cells, multiple replication forks of genomic DNA allows binary fission to occur before the genome has been fully duplicated.

FALSE

The duration of logarithmic growth would increase if bacterial cells divided into three equal daughter cells rather than two.

FALSE

The lag phase does NOT occur if all the cells in the culture are viable.

FALSE

The rates of exponential growth (in the exponential phase) vary greatly according to the bacterial species as well as the bioavailable nutrients.

TRUE

In both lag and stationary phase, there is no net increase or decrease in viable cells.

TRUE

The death phase applies to individual cells rather than populations

FALSE

Direct microscope counting of stained cells is an accurate method for calculating the exact number of cells in a sample.

TRUE

Counting chambers are used for estimating the number of cells present in a liquid culture

TRUE

For most purposes of studying bacterial isolates, viable counting usually gives accurate information about the number of active cells present in a culture volume.

TRUE

By using a stain targeting living cells only, microscopy would be a better approach to enumerate the number of living cells in a soil sample compared to viability counts of serially diluted soil.

TRUE

When viable cell concentrations are too high to count on an agar medium, it is most common to use larger sized plates to increase the surface area for counting the colonies

FALSE

In a chemostat, growth rate and growth yield can be controlled independently.

TRUE

Heterotrophic bacteria will run out of organic growth substrates in batch cultures but chemostats can provide constant nutrient source for them to grow. Chemostats for photoautotrophic bacteria are not necessary to maintain them at a constant growth phase because a light can artificially be turned on constantly.

FALSE

Identifying bactoprenol inside the rare bacteria that lack peptidoglycan would be unexpected considering its role in membrane biosynthesis.

TRUE

During elongation of a cell during binary fission, small gaps caused by transglycosylases are formed before cell membrane precursors can be inserted.

FALSE

One reason food is refrigerated to control microbial growth is because irreversible cell damage is more likely to occur at low rather than high temperatures.

FALSE

The optimum temperature is usually closer to the minimum temperature than the maximum temperature.

FALSE

A bacterium such as a snow alga that is able to survive a cold temperature is called a psychrophile.

FALSE

A non-aerated or shaken liquid growth medium inoculated with a bacterium is one of the best ways to culture an obligate anaerobe.

FALSE

Some microbes can grow in boiling water.

TRUE

Due to the relationship between the rate of enzyme catalysis and temperature, organisms living in boiling hot springs are also rapid growers with fast doubling times

FALSE

Taq polymerase was isolated from a thermophile and is used in the polymerase chain reaction (PCR) technique because it does not become inactivated at high temperatures.

TRUE

In principle, the chemical composition of membranes in obligate acidophiles could be distinguished from neutrophiles.

TRUE

The sensitivity of DNA and RNA is one major reason water activity can limit microbial growth.

FALSE

A bacterium's pH optimum reflects the optimal pH of its intracellular environment.

FALSE

Sterility of a laminar flow hood is accomplished by filter-sterilized air passed through the hood quickly enough that non-sterile air does not flow into the work area.

TRUE

An unpressurized autoclave would not be able to sterilize a growth medium with contaminating bacteria but could still pasteurize it.

TRUE

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