Q&A Hero

Q: A notorious biofilm former implicated in cystic fibrosis is A) Bacillus subtilis. B) Escherichia coli. C) Lactobacillus acidophilus. D) Pseudomonas aeruginosa.

Q: The abundance of cyanobacterial mats has greatly declined due to the evolution of A) antimicrobial-producing fungi. B) bacteriophages. C) metazoan grazers. D) Proteobacteria.

Q: Which of the following represents increasing microbial diversity? A) guild-community-population B) population-guild-community C) cell-community-population D) community-guild-population

Q: Which metric describes the proportion of EACH species present in a community? A) species abundance B) species diversity C) species evenness D) species richness

Q: Describe four environmental conditions that would likely change the relative abundances of the members within a microbial community.

Q: Explain why biofilms are a concern in medicine.

Q: What advantage do proteorhodopsin-containing organisms have over other heterotrophic microbes in the open ocean?

Q: Describe two roles viruses have in the open ocean.

Q: Explain how both biochemical oxygen demand and chemical oxygen demand are measured.

Q: Provide a reason for the ecological importance of pelagic Bacteria and Archaea.

Q: Describe three molecular effects high pressure has on the physiology of organisms.

Q: What is the difference between an organism being piezophilic and piezotolerant?

Q: Distinguish an ecotype from a species, and provide an example of an ecotype.

Q: Explain three reasons why bacteria form biofilms.

Q: In the context of nutrients, a sink is one that slowly releases a particular nutrient over time.

Q: Oligotrophic organisms do NOT grow well under nutrient-replete conditions.

Q: Archaea and Bacteria dominate the upper 100 m of the open ocean while viruses dominate depths greater than 100 m.

Q: Purple phototrophic bacteria that use bacteriochlorophyll a are oxygenic.

Q: Unlike other cyanobacteria, Prochlorococcus lacks phycobilins.

Q: Low return of nutrients in the pelagic zone results in relatively low primary production in the open ocean when compared to freshwater lake systems.

Q: In many marine systems, the carbon and oxygen cycles are directly proportional to each other.

Q: Gammaproteobacteria can be used for biodegradation of hydrocarbons.

Q: ALL stratified lakes contain a thermocline.

Q: Microbial life has been identified at depths of 3 km despite being anoxic.

Q: Functional differences can be observed by using 16S rRNA gene phylogenetics of a microbial community.

Q: Limiting nutrients in soils are generally organic compounds.

Q: Chemoorganotrophic bacteria can facilitate the formation of soil through the secretion of organic acids.

Q: Soil particles are classified based on their size.

Q: The formation of soil involves a combination of biological, chemical, and physical processes.

Q: Mineral soils largely come from weathered limestone and sand.

Q: The cells within a biofilm can undergo intra-species signaling; however, inter-species signaling does not occur.

Q: Due to such an array of nutrients, microorganisms are often capable of sustaining exponential growth in the environment.

Q: Arid soils are among the most extreme environments on earth.

Q: Cyclic di-guanosine monophosphate is upregulated as Pseudomonas aeruginosa cells are declining.

Q: Chemoheterotrophic bacteria are primary producers.

Q: A microbial population can contain several microbial communities.

Q: The physiochemical conditions of a microenvironment, by definition, remain static.

Q: Many microbial habitats are unsuitable for plants and animals.

Q: An ecosystem includes both the living organisms and abiotic materials that function together.

Q: The most abundant prokaryotic organism in the ocean is of the ________ genus. A) Pelagibacter B) Puniceispirillum C) Roseobacter D) Prochlorococcus

Q: Cyclic dimeric guanosine monophosphate (c-di-GMP) serves as a messenger molecule in bacterial cells to coordinate a shift from ________ to ________ growth. A) sessile / planktonic B) planktonic / sessile C) monomorphic / polymorphic D) stationary / exponential

Q: Cells within a biofilm excrete an adhesive matrix primarily composed of ________ but can also contain nucleic acids as well as proteins. A) lipids B) fatty acids C) monomers D) polysaccharides

Q: ________ use inorganic electron donors released from deep-sea hydrothermal vents. A) Chemolithotrophs B) Photoheterotrophs C) Chemoheterotrophs D) Photolithotrophs

Q: In the oceans, prokaryotes are outnumbered ten to one by A) zooplankton. B) diatoms. C) viruses. D) phytoplankton.

Q: Biomass generation due to heterotrophic organisms is called ________ production. A) primary B) secondary C) auxotrophic D) regulatory

Q: Two major environmental extremes of the deep sea are high ________ and low ________. A) pressure / nutrient levels B) nutrient levels / pressure C) temperature / pressure D) oxygen / pressure

Q: The microbial oxygen-consuming capacity of a water sample is called its A) chemical oxygen demand. B) biochemical capacity. C) biochemical oxygen demand. D) chemical capacity.

Q: Water in the rocks and soils of Earth's subsurface is called A) groundwater. B) surface water. C) subsurface water. D) deep water.

Q: Sudden nutrient perturbations in an environment generally ________ the overall prokaryotic diversity. A) increase B) decrease C) maintain D) replicate

Q: Propose a set of procedures or steps to sequence an individual cell's genome present in lake water.

Q: What prior knowledge is required to use a phylochip to study the abundance of the different microbes present within a microbial community? How does this cause bias when using a phylochip to analyze microbial community structure?

Q: Describe what an ITS region is in the context of prokaryotes, and explain the significance of the ITS region for microbial ecology.

Q: A study of the human gut performed in 1982 used various types of plates under different growth conditions to describe and enumerate the microbes in the human gut. They concluded that the majority of the microbes in the human gut are Gammaproteobacteria. A study conducted in 2010 using next-generation sequencing to characterize 16S rRNA sequences concluded that the majority of the microbes in the human gut are Firmicutes and Bacteriodetes. Why did these studies have different conclusions? Which study do you think is most accurate?

Q: Propose an experiment to identify members capable of assimilating monomers of lignin within a microbial community.

Q: Using specific examples, when is it appropriate to use CARD-FISH rather than the traditional FISH method and vice-versa?

Q: How can NanoSIMS be used to determine which Roseobacters most strongly use DMSP as a sulfur source within a coastal marine environment? Explain the NanoSIMS methodology in your answer.

Q: We know that that there are over 50 major phyla in Bacteria; however, only about 25 of these phyla have cultured representatives. Why is this? How are scientists attempting to culture representative from the 25 phyla that do not currently have any organisms in culture?

Q: Describe how FISH can be used to determine which cells within a microbial community are actively degrading toluene. Assume the genes involved in the metabolic pathway have been sequenced from several microorganisms and vary only slightly from one another.

Q: What are the pros and cons of traditional enrichment culture techniques? What advances in the last decade are improving enrichment culture techniques to aid the cultivation of uncultured microorganisms?

Q: Combined with autofluoresence or fluorescent DNA probes, flow cytometry can separate or count populations of cells from aquatic environments.

Q: Phototrophic organisms in SIP experiments are often observed releasing 14CO2 as measuring activity.

Q: Metaproteomics is a more developed field than metatranscriptomics due to the high sensitivity of mass spectrometry.

Q: The diversity of microorganisms in culture collections is representative of the diversity of microorganisms found in nature.

Q: Several fluorogenic dyes can be used simultaneously in a sample as long as they each emit light at a different measurable wavelength.

Q: By using simple microscopy techniques, it is possible to determine if a culture is contaminated with another organism.

Q: DGGE and T-RFLP are both molecular microbial ecology methods that use the polymerase chain reaction to amplify specific genes to assess diversity.

Q: In natural samples it is often difficult to differentiate live cells from dead cells or cells from nonliving matter.

Q: The Winogradsky column is a method for assessing the entire gene complement of a habitat, revealing both the biodiversity and metabolic capabilities of the microbial community at the same time.

Q: The MPN technique is rarely applied in the food industry because any microbial presence in food is unsafe.

Q: FISH technology can employ only a single phylogenetic probe.

Q: The goal of environmental genomics is to detect as many genes as possible and then, if possible, to determine to the phylogeny of the organisms to which the genes belong.

Q: Traditional enrichment culturing circumvents issues associated with "weed" species from overcoming the population.

Q: Organisms in natural environments can be detected by assaying for the presence of their genes.

Q: Once a putative pure culture has been obtained from the environment, it is no longer necessary to check its purity.

Q: If properly constructed, a Winogradsky column can be used to isolate pure cultures.

Q: Enrichment cultures can be established by placing the inoculum into selective media and incubating under specific conditions.

Q: The purpose of the enrichment culture technique is to enrich for organisms with specific physiological properties from a microbial community.

Q: Strict anaerobic organisms are not suited for GFP reporters due to the protein requiring oxygen to fluoresce.

Q: One way to study a microbial ecosystem is to isolate microorganisms from it and study their properties in laboratory culture.

Q: Which of the following statements is FALSE concerning enrichment bias? A) Dilution of the inoculum may help to avoid enrichment bias in some cases. B) Enrichment bias is impossible to overcome in some oligotrophic environments. C) Enrichment bias resulted in the underestimation of prokaryotic diversity. D) Enrichment bias favors organisms that grow quickly.