Microbiology Exam 3 Set 1

Which are the most dominant chemolithotrophs in pelagic waters? A) Ammonia-oxidizing Archaea B) Ammonia-oxidizing Bacteria C) Sulfate-reducing Bacteria D) Prochlorococcus

A) Ammonia-oxidizing Archaea

The photosynthetic pigments bacteriorhodopsin and proteorhodopsin are present in ________ and ________, respectively. A) Archaea / Bacteria B) Bacteria / Archaea C) Bacteria / Bacteria D) Bacteria / Eukarya

A) Archaea / Bacteria

Transcription of various genes under particular environmental conditions in natural populations can be studied using A) CARD-FISH. B) stable isotope analysis. C) T-RFLP. D) green fluorescent protein (GFP).

A) CARD-FISH.

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

A) Chemolithotrophs

________ is a term used to describe dead organic matter. A) Humus B) Loam C) Pyrite D) Xenocompost

A) Humus

How would you label and separate the DNA of unknown methylotrophs in a sample? A) Incubate the sample with 13C-methane. B) Hybridize the DNA to FISH probes. C) Use DGGE to separate the strands of DNA in the sample. D) Use T-RFLP to identify the methylotroph DNA in the sample.

A) Incubate the sample with 13C-methane.

From the aquatic systems below, where are heterotrophic Bacteria the most abundant? A) Marine coastal waters B) Deep sea C) Sargasso Sea D) Open ocean

A) Marine coastal waters

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

A) Pelagibacter.

________ are the main primary producers in freshwater environments. A) Phototrophic microorganisms B) Heterotrophic microorganisms C) Chemolithotrophic microorganisms D) Viral microorganisms

A) Phototrophic microorganisms

According to bacterial abundance studies done so far on soils, the ________ represent the most abundant phylum. A) Proteobacteria B) Acidobacteria C) Actinobacteria D) Firmicutes

A) Proteobacteria

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

A) Species abundance

An organism living in the bottommost region of a body of water is described as being A) benthic. B) litoral. C) neritic. D) pelagic.

A) benthic.

All Prochlorococcus strains contain the pigments A) chlorophylls a and b, but not phycobilins. B) chlorophyll a and phycobilins, but not chlorophyll b. C) chlorophyll b and phycobilins, but not chlorophyll a. D) chlorophylls a and b and phycobilins.

A) chlorophylls a and b, but not phycobilins.

In a stratified lake, the warmer and less dense layer is called the A) epilimnion. B) hypolimnion. C) metalimnion. D) thermocline.

A) epilimnion

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

A) groundwater.

A population of metabolically related microorganisms is called a(n) A) guild. B) niche. C) ecosystem. D) haplotype.

A) guild.

Thirty organisms containing the same phylogenetic marker, with identical or similar orthologous genes, are all considered to be within the same A) phylotype. B) species. C) functional group. D) phylogenetic tree.

A) phylotype.

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

A) pressure / nutrient levels

Phylogenetic stains, such as those used in phylogenetic FISH, hybridize with A) ribosomal RNA. B) mitochondrial DNA. C) nuclear DNA. D) RNA polymerase.

A) ribosomal RNA.

When dealing with stable isotopes of carbon and sulfur, enzymes tend to favor A) the lighter isotope. B) the heavier isotope. C) the isotopes in about equal proportions. D) either the lighter or the heavier isotope, depending on environmental conditions.

A) the lighter isotope.

Diversity is often ________ when T-RFLP is used. A) underestimated B) overestimated C) randomly overestimated or underestimated D) impossible to estimate

A) underestimated

Why is it necessary to have a standard for the interpretation of stable isotope ratios? A) A standard is necessary to calculate how rapidly the stable isotopes undergo radioactive decay. B) A standard is necessary to determine the stable isotope ratio in the absence of biological activity. C) A standard is necessary because samples are only presented in comparison with other samples of the same age. D) A standard is necessary to determine the age of the sample.

B) A standard is necessary to determine the stable isotope ratio in the absence of biological activity.

Which of the following hypotheses could be tested using microautoradiography fluorescence in situ hybridization (MAR-FISH)? A) Bacteriorhodopsin uses light energy to translocate protons. B) Archaea are the main autotrophs in marine water samples taken 300 m below the surface of the ocean. C) The microbial community of agricultural soils is more phylogenetically diverse than the microbial community of native prairie soils. D) The ammonia monooxygenase gene is present in members of the phylum Verrucomicrobium.

B) Archaea are the main autotrophs in marine water samples taken 300 m below the surface of the ocean.

Which is the correct order of increasing size in soil particles? A) Clay - sand - silt B) Clay - silt - sand C) Sand - clay- silt D) Silt - clay - sand

B) Clay - silt - sand

Which of the following is an example of a biofilm? A) Transient skin microbes B) Dental plaque C) Marine diatoms D) A planktonic microcolony

B) Dental plaque

Which approach would help to identify biologically produced sulfur in a sediment sample? A) Enrichment B) Isotopic fractionation C) Microautoradiography D) Microelectrodes

B) Isotopic fractionation

Which method requires the addition of at least one radioactive chemical? A) CARD-FISH B) MAR C) GeoChips D) SIP

B) MAR

Which of the following represents increasing microbial diversity? A) Guild-community-population B) Population-guild-community C) Cell-community-population D) Community-guild-population

B) Population-guild-community

Which statement is TRUE about the fluid from the hydrothermal vents? A) The fluid contains large amounts of oxidized inorganic materials. B) The fluid contains large amounts of reduced inorganic materials. C) The fluid contains large amounts of organic material. D) The fluid usually contains about equal amounts of organic and inorganic material.

B) The fluid contains large amounts of reduced inorganic materials.

How does the concentration of prokaryotic cells at the surface of pelagic water compare with the concentrations at depths below 1000 m? A) There is a decrease in concentration from 1 m to 1000 m in depth, then a dramatic increase below 1000 m. B) There is a decrease in concentration with increasing depth. C) There is a steady increase in concentration with increasing depth. D) There is an increase in concentration at depths below 1000 m.

B) There is a decrease in concentration with increasing depth.

When laser tweezers are used, the laser beam can trap A) an isolated single-copy genome in a capillary tube. B) a single microbial cell in a capillary tube. C) a single microbial colony on a plate. D) multiple cells of the same type on a plate.

B) a single microbial cell in a capillary tube.

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

B) decrease

During periods of stratification, transfer between surface and bottom waters is controlled by A) mixing. B) diffusion. C) niche partitioning. D) current.

B) diffusion.

For microbial biodiversity studies, it is common to identify the ________ rather than the ________ as a measure of biodiversity. A) organisms themselves / genes B) genes / organisms themselves C) cell types / genes D) cell types / organisms themselves

B) genes / organisms themselves

Laser tweezers are most directly used for A) enriching a culture. B) isolating individual cells. C) increasing magnification. D) enhancing the growth of fastidious organisms.

B) isolating individual cells.

Interpreting stable isotopic fractionation depends on the fact that most enzymes preferentially bind ________ isotope substrates over ________ isotope substrates. A) nonradioactive / radioactive B) light / heavy C) heavy / light D) radioactive / nonradioactive

B) light / heavy

Epsilonproteobacteria are most dominant in hydrothermal vents because they A) reduce nitrogen. B) oxidize sulfide and sulfur as electron donors. C) use oxygen as electron acceptors. D) bind divalent cations.

B) oxidize sulfide and sulfur as electron donors.

Staining methods are suitable for obtaining A) information about physiology from natural samples. B) quantitative information from natural samples. C) phylogenetic information from natural samples. D) neither qualitative nor quantitative information from natural samples.

B) quantitative information from natural samples.

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

B) secondary

Genes encoding ________ are widely used as target genes in molecular biodiversity studies. A) ATPases B) DNA polymerase III C) 16S rRNA D) RNA polymerase

C) 16S rRNA

What are activity measurements? A) Activity measurements are any measurements taken in vitro. B) Activity measurements are any measurements taken in situ. C) Activity measurements are collective estimates of the physiological reactions in an entire microbial community. D) Activity measurements are an example of metagenomics, which can be used when genetic analysis is difficult.

C) Activity measurements are collective estimates of the physiological reactions in an entire microbial community.

Which fluorescent molecule enables visualization of living microorganisms? A) Acridine orange B) DAPI C) GFP D) SYBR® Green

C) GFP

Which technique would be used to estimate the concentration of naturally occurring Escherichia coli in a wastewater sample? A) Agar dilution tube method B) Laser tweezers method C) Most probable number (MPN) method D) Cell tagging using GFP method

C) Most probable number (MPN) method

Which of the following is/are NOT a degradation product of organic material? A) Carbon dioxide B) Methane C) Oxygen D) All of these answer choices are degradation products of organic material.

C) Oxygen

What unit is isotopic fractionation reported as? A) Parts per billion B) Parts per hundred C) Parts per thousand D) Parts per trillion

C) Parts per thousand

Phylogenetic analyses of marine prokaryotic diversity in both shallow and deep-sea marine sediments have found that both types of sediments are dominated by A) Firmicutes. B) Planctomycetes. C) Proteobacteria. D) Chloroflexi.

C) Proteobacteria.

Which of the following is NOT an oxygenic phototrophic microorganism present in marine waters? A) Ostreococcus B) Prochlorococcus C) Roseobacter D) Trichodesmium

C) Roseobacter

You would like to test the hypothesis that ammonia-oxidizing Archaea are more active and abundant than ammonia-oxidizing Bacteria in coastal marine water. What technique(s) or experiment(s) could you use to test this hypothesis? A) Environmental proteomics B) Fluorescent in situ hybridization (FISH) C) Stable isotope probing using 15N labeled ammonia D) Stable isotope ratios of ammonia and nitrite

C) Stable isotope probing using 15N labeled ammonia

How do viability stains usually distinguish between living cells and dead cells? A) The chemical fluoresces only when bound to ribosomes that are actively synthesizing proteins. B) The chemical stain is taken up by living cells and once metabolized becomes fluorescent. C) The dye specifically targets intact cytoplasmic membranes. D) The dye's fluorescence is quenched by dead cells.

C) The dye specifically targets intact cytoplasmic membranes.

Winogradsky columns are used primarily for enrichment of A) aerobic cultures, although occasionally anaerobes do appear. B) anaerobic cultures, although occasionally aerobes do appear. C) aerobes, anaerobes, and phototrophs. D) phototrophs, although occasionally heterotrophs do appear.

C) aerobes, anaerobes, and phototrophs.

Analyses of sulfur isotopes have been used as evidence against life on the Moon, because the sulfides in lunar rocks have A) an isotope composition most similar to marine sulfate, which is enriched in 34S. B) an isotope composition most similar to marine mud, which is enriched in 34S. C) an isotope composition most similar to igneous rocks. D) exactly equal amounts of 34S and 32S.

C) an isotope composition most similar to igneous rocks.

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

C) animal grazers.

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.

C) biochemical oxygen demand.

Well-designed microbial activity measurements can reveal ________ of major metabolic reactions in a habitat. A) types B) rates C) both types and rates D) either types or rates (but not both)

C) both types and rates

WATCH THIS ANSWER Amplification of chromosomal DNA from a single-cell is accomplished by A) using PhyloChips. B) using multiple displacement amplification. C) creating complementary DNA from transcripts of a single-cell. D) cloning fragments of the chromosome from the single-cell into a multi-copy plasmid.

C) creating complementary DNA from transcripts of a single-cell.

In an agar dilution tube, microbial colonies grow A) at the bottom of the tube. B) on the sides of the tube, although some may be at the surface. C) embedded in the agar, rather than growing on the surface. D) on the surface, but some creep down the sides away from the surface.

C) embedded in the agar, rather than growing on the surface.

Metatranscriptomics and metaproteomics are favored over metagenomics when ________ is of more interest than ________. A) gene presence / phylogeny B) phylogeny / gene presence C) function or gene expression / gene presence D) gene presence / function or gene expression

C) function or gene expression / gene presence

The biggest limitation of traditional light microscopy and electron microscopy is that they are unable to reveal A) absolute cell concentration. B) cellular components of small microbes because of the limits of magnification. C) functional diversity of microorganisms in the habitat under study. D) physical microbial interactions as found in nature.

C) functional diversity of microorganisms in the habitat under study.

Culture-independent approaches avoid issues associated with A) detecting very rare phylotypes. B) conflating phylogenetic and functional diversity. C) growing organisms in the lab. D) next generation sequencing.

C) growing organisms in the lab.

The 13C/12C isotopic ratio of geological rocks of different ages has been used to examine whether previous biological activity occurred because compounds of biological origin A) do NOT contain 13C. B) have a higher proportion of 13C that compounds of geological origin. C) have a lower proportion of 13C that compounds of geological origin. D) are not well preserved in geological samples.

C) have a lower proportion of 13C that compounds of geological origin.

In microbial ecology studies, the FISH technique identifies organisms based on A) the presence of green fluorescent protein. B) fluorescence of unique cofactors or pigments under certain wavelengths of UV light. C) hybridization of a fluorescent probe to specific ribosomal RNA sequences. D) the presence of luciferase.

C) hybridization of a fluorescent probe to specific ribosomal RNA sequences.

The term used when an organism is studied in its natural environment is A) au naturale. B) in vitro. C) in situ. D) in toto.

C) in situ.

A soil that lacks a dominant particle size is referred to as a(n) A) aggregation. B) bisequum. C) loam. D) mottled soil.

C) loam.

Sedimentation in bogs and marshes develops ________ soils. A) inorganic B) mineral C) organic D) loamy

C) organic

Ecological theory states that for every organism there is AT LEAST one ________, and the microenvironment where the organism is most successful is called the ________. A) population / community B) niche / realized niche C) prime niche / niche D) community / population

C) prime niche / niche

The proportion of Roseobacter species in the ocean describes A) species diversity. B) species richness. C) species abundance. D) species prevalence.

C) species abundance.

Some nitrifying prokaryotes carry out metabolic cooperation by a process known as A) competition. B) niche partitioning. C) syntrophy. D) antagonism.

C) syntrophy

Stable isotope probing (SIP) is a method that A) causes cells that hybridize with a fluorescent probe to fluoresce under UV light. B) compares the isotopic ratios of different compounds in the environment to determine whether they are of biological or geological origin. C) uses substrates containing heavy isotopes to label the DNA of organisms that use those substrates. D) compares the transcription of specific isotope labeled genes under different conditions.

C) uses substrates containing heavy isotopes to label the DNA of organisms that use those substrates.

In the oceans, prokaryotes are greatly outnumbered by A) zooplankton. B) diatoms. C) viruses. D) phytoplankton.

C) viruses.

Assuming exposure to the same climate, which of the following aquatic systems would be most stratified? A) 20 m deep freshwater river B) 50 m deep marine water fjord C) 200 m deep saltwater lake D) 300 m deep freshwater lake

D) 300 m deep freshwater lake

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.

D) Enrichment bias favors organisms that grow quickly.

Which of the following techniques can link prokaryotic phylogeny and metabolic function? A) DAPI staining B) Stable isotope probing only C) Environmental genomics only D) Environmental genomics and stable isotope probing

D) Environmental genomics and stable isotope probing

What technique(s) can be used to characterize the phylogenetic composition of a microbial community without culturing any of the members? A) Green fluorescent protein tagging B) Stable isotope techniques C) Radioisotope experiments D) Fluorescent in situ hybridization (FISH)

D) Fluorescent in situ hybridization (FISH)

Which molecular method allows for the detection of a specific organism within a diverse microbial community? A) Fluorescent DNA staining using DAPI B) Viability staining C) Enrichment techniques D) Fluorescent in situ hybridization (FISH)

D) Fluorescent in situ hybridization (FISH)

What adaptation allows organisms to tolerate high pressures? A) Decreased cell size B) Decreased lipid content C) Increased ribosome size D) Increased unsaturated fatty acids

D) Increased unsaturated fatty acids

Which aquatic habitat contains a pelagic zone? A) Estuary B) Lake C) Salt marsh D) Open ocean

D) Open ocean

Which organisms form the foundation of the carbon cycle? A) Anaerobic chemolithotrophs B) Chemoheterotrophs C) Chemoorganotrophs D) Phototrophs

D) Phototrophs

________ is the phylogenetic group most abundant in terrestrial soils. A) Bacteroidetes B) Acidobacteria C) Firmicutes D) Proteobacteria

D) Proteobacteria

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

D) Pseudomonas aeruginosa.

Which metabolic strategy is most common in chemolithotrophic mats? A) Ammonia oxidation B) Iron oxidation C) Nitrate reduction D) Sulfur oxidation

D) Sulfur oxidation

Which of the following methods do NOT involve nucleic acid hybridization of a probe to a specimen? A) RACE-FISH B) FISH-MAR C) PhyloChips D) T-RFLP

D) T-RFLP

In deep pelagic waters, the archaeal species present are almost all members of A) Crenarchaeota. B) Euryarchaeota. C) Nanoarchaeota. D) Thaumarchaeota.

D) Thaumarchaeota.

For what purpose would a microbial ecologist use a microsensor? A) To determine the concentration of cells in small increments in a sediment or water column B) To determine the expression of a particular gene in a microbial community C) To quantify the uptake of a radioactive material D) To determine the concentration of O2, N2O, or other chemical species in small increments in a sediment or water column

D) To determine the concentration of O2, N2O, or other chemical species in small increments in a sediment or water column

Robotic systems used to quickly test the response of microbes in microtiter plates to thousands of combinations of nutrients is an example of ________ technology. A) a next generation sequencing B) a stable isotope C) a genomic D) a high-throughput

D) a high-throughput

The term axenic is used to describe A) an anaerobic culture. B) an anoxygenic culture. C) a nutritionally deficient culture. D) a pure culture.

D) a pure culture.

A population consists of A) all of the individuals of all species in the same area. B) all of the individuals of one species in the same area. C) all of the individuals that interact in different areas. D) all of the individuals that interact in the same area.

D) all of the individuals that interact in the same area.

The element(s) that have proven most useful for stable isotope studies are A) carbon only. B) nitrogen only. C) sulfur only. D) carbon, sulfur, and sometimes nitrogen.

D) carbon, sulfur, and sometimes nitrogen.

The methodology of microbial ecology includes A) enrichment and isolation of specific microbes. B) cell-staining methods. C) gene, transcript, and protein characterization. D) enrichment and isolation of specific microbes, cell-staining, and characterization of genes, transcripts, and proteins.

D) enrichment and isolation of specific microbes, cell-staining, and characterization of genes, transcripts, and proteins.

Microarrays are useful for assessing A) gene expression only. B) enzyme activity. C) the presence of specific rRNA sequences only. D) gene expression and the presence of specific rRNA sequences.

D) gene expression and the presence of specific rRNA sequences.

Genomic analysis of Prochlorococcus has revealed A) the presence of bacteriorhodopsin. B) that no regions are shared between cultured representatives and environmental populations. C) complete congruence of genes and genome structure within the same phylotype. D) high levels of gene conservation between cultured representatives and environmental populations.

D) high levels of gene conservation between cultured representatives and environmental populations.

The science of microbial ecology deals with A) how microbial communities interact with each other and their environment. B) microbial activity and biodiversity. C) microbial gene regulation mechanisms in response to environmental change. D) how the activity and biodiversity of microbial communities affect microbial interactions with each other and the environment.

D) how the activity and biodiversity of microbial communities affect microbial interactions with each other and the environment.

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

D) polysaccharides

The overall purpose of DGGE is to A) separate genes that differ in length. B) measure the activity of cells that use DGGE as an energy source. C) detect cells that utilize a specific radiolabeled substrate. D) separate genes of the same length that have different sequences, resulting in different denaturation profiles.

D) separate genes of the same length that have different sequences, resulting in different denaturation profiles.

The generation time of Escherichia coli in the human intestine is ________ in laboratory culture. A) at about the same rate as B) faster than C) more optimal than D) slower than

D) slower than

Pure cultures can be obtained from an enrichment culture using A) streak plates only. B) the agar dilution method only. C) liquid dilution methods only. D) streak plates, the agar dilution method, or liquid dilution methods.

D) streak plates, the agar dilution method, or liquid dilution methods.

In the soil, oxygen concentrations are highly variable even within a soil particle. The center of the particle may be anoxic even if the outer portions are oxygen rich. In this context, facultative anaerobes could be found A) at the surface of the particle. B) in the center of the particle. C) in the middle regions of the particle. D) throughout the particle.

D) throughout the particle.

Single-cell genomics may help us A) predict which microbes will be abundant based on the environmental conditions. B) understand the physiology of uncultured microbes. C) develop better enrichment culture methods. D) understand the physiology of uncultured microbes and develop better enrichment culture methods.

D) understand the physiology of uncultured microbes and develop better enrichment culture methods.

Radioisotopes are useful when A) very high sensitivity is required. B) turnover rates need to be determined. C) the fate of portions of particular molecules need to be followed. D) very high sensitivity is required, turnover rates need to be determined, and the fate of portions of particular molecules need to be followed.

D) very high sensitivity is required, turnover rates need to be determined, and the fate of portions of particular molecules need to be followed.