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Biology & Life Science
Q:
Why are some xenobiotics biodegraded slower than crude oil and petroleum products?
A) Xenobiotics were designed to inhibit microbial growth.
B) Some xenobiotics are novel compounds that differ from naturally occurring chemicals, thus microorganisms have not yet evolved to effectively degrade them.
C) Only cometabolic microbial processes degrade xenobiotics.
D) Chlorinated compounds are so toxic that biodegradation is not possible.
Q:
Crown corrosion of concrete wastewater distribution systems is the result of
A) acidic fermentation products reacting with the gypsum in the concrete.
B) sulfate reduction in the sewage and sulfide oxidation in the oxic headspace above.
C) fungal growth in the concrete.
D) rapid iron reduction coupled to pyrite dissolution.
Q:
The production of ________ by ________ is thought to be a major contributor to the biodeterioration of stone building materials.
A) oxalic acid / fungi
B) sulfuric acid / sulfate reducers
C) nitric acid / nitrate reducers
D) carbonic acid / lichens
Q:
Which group of organisms is thought to be responsible for the corrosion of submerged metal structures and oil pipelines?
A) fermentative microorganisms
B) acidophilic iron-oxidizers
C) sulfate reducers
D) hydrocarbon-degrading anaerobes
Q:
To prevent the souring of crude oil, ________ is added to oil well injection water to encourage ________ instead of ________.
A) oxygen / aerobic respiration / sulfate reduction
B) sulfate / sulfate reduction / fermentation
C) sulfate / sulfate reduction / nitrate reduction
D) nitrate / nitrate reduction / sulfate reduction
Q:
Synthetic plastics are
A) oxidized completely to carbon dioxide after a few years under aerobic conditions.
B) partially degraded into branched chain and polyaromatic hydrocarbons.
C) degraded slowly under anoxic conditions.
D) extremely recalcitrant to microbial degradation.
Q:
Microbial plastics are composed of
A) polysaccharides.
B) polyhydroxyalkanoates.
C) polyaromatic hydrocarbons.
D) xenobiotics.
Q:
Reductive dechlorination is a process in which
A) the number of chlorine atoms present is reduced by oxygenase enzymes.
B) chlorinated organics are used as terminal electron acceptors in anaerobic respiration.
C) carbon dioxide is the final end product.
D) xenobiotics are cometabolized with other reductive reactions.
Q:
Reductive dechlorination is important in the breakdown of chlorinated xenobiotics because
A) anoxic conditions develop rapidly in polluted habitats.
B) oxygen is not present in most soils.
C) aerobic breakdown of xenobiotics is not possible.
D) only cometabolism occurs aerobically.
Q:
Which of the following hydrocarbon compounds are MOST recalcitrant?
A) straight-chain hydrocarbons
B) ethane
C) polycyclic hydrocarbons
D) propane
Q:
Based on your knowledge of hydrocarbon degradation, what factors most likely limited the rate of petroleum degradation after the Exxon Valdez oil spill off the coast of Alaska?
A) salt concentration
B) temperature
C) inorganic nutrient concentrations
D) temperature and inorganic nutrient concentrations
Q:
Which of the following can be completely degraded to carbon dioxide by microorganisms?
A) petroleum
B) uranium
C) chlorinated organics
D) petroleum and chlorinated organics
Q:
Microbial immobilization is the best strategy for uranium bioremediation, because
A) uranium is difficult to chemically oxidize.
B) uranium contamination is widespread and thus difficult to physically remove.
C) the by-products of chemical immobilization are toxic.
D) immobilization may only be temporary.
Q:
Bioremediation of uranium depends on
A) fermentation and oxidation.
B) methanogens.
C) metal-reducing bacteria.
D) metal-oxidizing bacteria.
Q:
The propagation cycle that occurs in acid mine drainage is caused by
A) reduction of Fe3+ by sulfuric acid.
B) the oxidation of sulfide to sulfuric acid by microbial oxidation of iron (Fe3+).
C) microbial sulfate reduction.
D) low pH and high oxygen concentrations.
Q:
What chemical initiates the formation of acid mine drainage when pyrite is not disposed of properly?
A) O2
B) Fe2+
C) HS-
D) SO42-
Q:
What role does Acidithiobacillus ferrooxidans play in the copper leaching process?
A) oxidation of sulfide to sulfate
B) reduction of oxidized iron (Fe3+) to reduced iron (Fe2+)
C) oxidation of reduced iron (Fe2+) to oxidized iron (Fe3+)
D) reduction of sulfate to sulfide
Q:
Which of the following is the first, or initiator, reaction in acid mine drainage and leaching?
A) oxidation of reduced sulfides to sulfate and the release of reduced iron (Fe2+)
B) rapid spontaneous reduction of oxidized iron (Fe3+)
C) rapid oxidation of sulfides to sulfate by oxidized iron (Fe3+)
D) microbial sulfate reduction
Q:
Treatment of drinking water by UV irradiation is effective at ________, but it does NOT remove ________.
A) killing bacteria and eukaryotic pathogens / odor- and taste- altering organic compounds
B) killing viruses / bacteria and eukaryotic pathogens
C) removing order- and taste- altering organic compounds / viruses
D) killing bacteria / viruses and eukaryotic pathogens
Q:
The goal of tertiary wastewater treatment is to sharply reduce the levels of ________ from the final effluent.
A) organic compounds
B) heavy metals
C) methane
D) inorganic nutrients
Q:
Opportunistic pathogens such as Legionella, Pseudomonas, and Mycobacterium species have the ability to grow within ________, which may enhance their ability to survive in water distribution systems.
A) human saliva
B) fish
C) protists
D) UV irradiated water
Q:
Water distribution systems contain
A) very few bacteria or other microorganisms.
B) biofilms that may harbor opportunistic pathogens.
C) numerous grazing protists that consume bacteria.
D) biofilms that may harbor opportunistic pathogens and numerous grazing protists that consume bacteria.
Q:
The goal of wastewater treatment is to
A) produce potable water.
B) remove pathogens from wastewater before it is released.
C) reduce organic and inorganic materials in wastewater to a level that no longer supports microbial growth.
D) remove pathogens from wastewater to produce potable water.
Q:
Which process produces a gaseous product that can be used as fuel to provide heat or power for a wastewater treatment plant?
A) trickling filter secondary wastewater treatment
B) aerobic secondary wastewater treatment
C) anaerobic secondary wastewater treatment
D) primary wastewater treatment
Q:
The use of ________ to treat drinking water, which began in 1913, reduces the incidence of waterborne diseases.
A) coagulation
B) chlorination
C) filtration
D) UV irradiation
Q:
Which of the following bacterial pathogens is found in water distribution systems?
A) Enterobacter aerogenes
B) Klebsiella pneumoniae
C) Legionella pneumophila
D) Vibrio cholerae
Q:
Microbes are involved in which step(s) of wastewater treatment?
A) primary only
B) secondary and tertiary
C) secondary only
D) primary and secondary
Q:
Effluent water is wastewater
A) discharged from the pharmaceutical, plastics, and petrochemical industries.
B) discharged from the wastewater treatment facility.
C) that has undergone anoxic secondary wastewater treatment.
D) that is imported to the wastewater treatment facility for treatment.
Q:
Secondary disinfection of drinking water is necessary to
A) maintain sufficient residual in the water distribution system to inhibit microbial growth.
B) prevent the formation of biofilms on pipes in the water distribution system.
C) neutralize taste- and odor-producing organic compounds.
D) kill Cryptosporidium and other resistant pathogens.
Q:
What is the advantage of enhanced biological phosphorus removal (EBPR) over chemical precipitation?
A) Chemical precipitation produces sludge containing arsenic.
B) EBPR removes significantly more phosphorus than chemical precipitation.
C) Significantly less sludge is produced by EBPR compared to chemical precipitation.
D) EBPR is a more stable process.
Q:
To further reduce the possibility of biological contamination, MOST treatment plants treat the effluent with
A) fluorine.
B) chlorine.
C) ozone.
D) extreme heat.
Q:
While wastewater is in an activated sludge tank, much of the organic matter is
A) oxidized.
B) adsorbed to the floc.
C) incorporated into microbial cells.
D) oxidized, adsorbed to the floc, and incorporated into microbial cells.
Q:
During secondary aerobic wastewater treatment, some of the activated sludge goes ________ while the rest goes ________.
A) back to the aerator / to the anoxic sludge digestor
B) back to the primary system / to the aerator
C) to the anoxic digestor / back to the primary system
D) back to the primary system / to the tertiary digestor
Q:
Aerobic secondary treatment is usually best for ________ wastewater.
A) industrial
B) agricultural
C) residential
D) chemical
Q:
Which product of anoxic sewage treatment can be used to heat and power an entire water treatment facility?
A) CO2
B) H2
C) CH4
D) O2
Q:
Which treatment method(s) are used in primary wastewater treatment?
A) biological
B) chemical
C) physical separation
D) biological, chemical, and physical separation
Q:
Water leaving an efficient wastewater treatment facility ideally has a biochemical oxygen demand (BOD) between ________ units.
A) 50 and 100
B) 25 and 50
C) 5 and 25
D) 0 and 5
Q:
With increased levels of oxidizable materials, the biochemical oxygen demand (BOD) will
A) increase.
B) decrease.
C) remain the same.
D) increase or decrease depending on the nature of the materials involved.
Q:
Microbes are sometimes used in secondary treatment of wastewater to
A) convert heavy metals into carbon dioxide.
B) remove organic matter.
C) remove large particles.
D) convert heavy metals into carbon dioxide, remove organic matter, and remove large particles.
Q:
Which statement BEST describes sewage and wastewater?
A) Wastewater is a subset of sewage.
B) Sewage is a subset of wastewater.
C) Wastewater and sewage are virtually synonymous.
D) Wastewater and sewage are both subsets of all liquid effluents from domestic and industrial sources.
Q:
Describe how syntrophy helps explain why certain enrichments yield consortia and never an individual species.
Q:
Why is sulfur cycling more complex to study than other nutrient cycles such as the nitrogen cycle? How might this influence researchers whose primary research interest is in understanding sulfur cycling?
Q:
How are the Ca cycle and the C cycle linked in marine environments? How will increased carbon dioxide from anthropogenic activity affect the Ca and C cycling in marine environments?
Q:
Why does the burning of fossil fuels cause an imbalance within the carbon cycle? What is the consequence of this imbalance? Include a diagram of the carbon cycle to illustrate your answer.
Q:
Draw a microbial-based nitrogen cycle. In the open ocean there is plenty of sunlight and carbon dioxide for primary production, yet photosynthesis is limited in the open ocean compared to other aquatic environments. What limits photosynthesis in the open ocean?
Q:
Marine wetlands (salt marshes) are highly productive coastal ecosystems that produce a lot of organic carbon, similar to freshwater wetlands; however, salt marshes smell very different than freshwater wetlands. What nutrient cycle is different between the two ecosystems that causes this difference in smell?
Q:
How would Si depletion in the photic zone of the open ocean affect the biological pump and the C cycle?
Q:
Why is the water solubility of different nitrogen species of importance to agriculturalists? What processes in the nitrogen cycle are LEAST beneficial to agricultural production of crops?
Q:
Coal contains substantial amounts of mercury. When coal is burned to generate heat or electricity, the mercury is released into the atmosphere. Most of this mercury is eventually deposited in the ocean or other aquatic environments. What happens to the mercury once it is deposited in the ocean?
Q:
What are the similarities and differences between the Fe cycle and Ca cycle?
Q:
Using the sudden bloom of cyanobacteria in a lake due to anthropogenic fertilizer inputs as an example, explain the coupling of carbon, nitrogen, and oxygen cycling. Exclude discussion of all organisms other than microorganisms.
Q:
The two main biological activities in the Ca and Si cycles are the biosynthesis of shells and exoskeletal material as well as the mineralization of these materials in sediments.
Q:
Denitrification of fertilizer can result in harmful algal blooms.
Q:
Calcium is cycled most rapidly in terrestrial environments.
Q:
Mercury-resistant bacteria detoxify mercury by producing Hg0.
Q:
Microbial activity generates methylmercury, which is much less toxic than the mercuric ion.
Q:
Mercury can serve as a transcriptional activator in the regulation of certain genes.
Q:
Some bacteria have genes that confer resistance to mercury.
Q:
The mercury in fish is normally in the form of elemental mercury (Hg0).
Q:
Mercury has both organic and inorganic forms that are neurotoxic.
Q:
Ocean acidification decreases the precipitation of calcium carbonate and thus will probably affect the cycling of Ca and other nutrients in the ocean.
Q:
Carbon dioxide is the only greenhouse gas produced by anthropogenic activities.
Q:
Silicoflagellates use silicon compounds in substrate-level phosphorylation.
Q:
Most phosphorous, such as that found in inorganic phosphate (HPO4-), exist in the +5 oxidation state in nature.
Q:
Energy yields are high enough for Fe2+ oxidation that the bacteria that perform this reaction require only small quantities of Fe2+ to be available.
Q:
Abiotic oxidation of Fe2+ requires oxygen; no other chemicals can directly oxidize Fe2+.
Q:
The precipitation of soluble iron ions into solid iron occurs spontaneously in the presence of organic carbon compounds.
Q:
Most chemolithotrophic bacteria that oxidize sulfur are aerobes.
Q:
The disposal of garbage or sewage in the ocean is known to cause the sudden growth of sulfate reducers.
Q:
When carbon is limiting in a system, sulfate reducers often predominate the system when sufficient sulfate ions are present for reduction.
Q:
Acetogens can ferment glucose into acetate, but methanogens cannot.
Q:
Syntrophic organisms cannot grow fermentatively without a hydrogen-consuming partner organism.
Q:
Methanogens, among other compounds, use alcohols and fatty acids to synthesize methane gas in anoxic environments.
Q:
In a global sense, ALL nutrient cycles are coupled together.
Q:
Climate scientists are developing methane hydrates to decrease the effects of global warming.
Q:
Humic acids are difficult to degrade, and therefore they usually remain in a system for several decades.
Q:
More carbon is present in dead organic material on Earth than in living organisms.
Q:
In the natural carbon cycle, carbon dioxide is returned to the atmosphere by the respiration of animals and chemoorganotrophic microorganisms.
Q:
Human activities have disrupted the carbon cycle by
A) burning carbon stored as fossil fuels or biomass, thus increasing the amount of carbon dioxide in the atmosphere.
B) decreasing the primary productivity of the oceans, resulting in increased atmospheric carbon dioxide.
C) burning methane hydrates to produce electricity.
D) acidifying the ocean, resulting in the release of large amounts of dissolved carbon dioxide into the atmosphere.
Q:
The oxidation of ________ occurs both biotically and abiotically; however, at ________ pH values biotic oxidation is more common.
A) Si / low
B) ammonia / high
C) Fe2+ / low
D) Hgo / low