ch 19

Which fluorescent molecule enables visualization of living microorganisms? DAPI SYBR® Green GFP acridine orange

GFP

The methodology of microbial ecology includes cell-staining methods. enrichment and isolation of specific microbes, cell-staining, and gene, transcript, and protein characterization. enrichment and isolation of specific microbes. gene, transcript, and protein characterization.

enrichment and isolation of specific microbes, cell-staining, and gene, transcript, and protein characterization.

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

False

The diversity of microorganisms in culture microorganisms found in nature. True False

False

The element(s) that have proven useful for stable isotope studies are carbon, nitrogen, and sulfur. nitrogen. sulfur. carbon.

carbon, nitrogen, and sulfur.

Phylogenetic stains, such as those used in FISH, hybridize with ribosomal RNA. nuclear DNA. mitochondrial DNA. RNA polymerase.

ribosomal RNA.

Which approach would help to identify biologically produced sulfur in a sediment sample? isotopic fractionation microautoradiography microelectrodes enrichment

isotopic fractionation

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

True

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

True

The term axenic is used to describe a(n) pure culture. anoxygenic culture. anaerobic culture. nutritionally deficient culture.

pure culture.

A NASA ecologist wants to design an instrument to send to Mars on the next space probe to determine whether living organisms ever carried out carbon fixation on that planet. Suggest an assay that she could use on Martian soil samples. 13C/12C stable isotope analysis NanoSIMS 34S/35S stable isotope analysis MAR-FISH

13C/12C stable isotope analysis

What is the process that will amplify DNA from a single cell isolated from a natural microbial community? polymerase chain amplification multiple displacement amplification polymerase chain reaction You cannot amplify the DNA from a single cell isolated from an environmental sample.

multiple displacement amplification

When dealing with stable isotopes, enzymes tend to favor the isotopes in about equal proportions. the heavier isotope. the lighter isotope. either the lighter or the heavier isotope, depending on environmental conditions.

the lighter isotope.

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

Enrichment bias favors organisms that grow quickly.

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

False

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

The dye specifically targets intact cytoplasmic membranes.

There is a small lake on campus that students like to use for recreational activities. A study has begun on the microbial community in the lake at different times of the year. In order to quickly determine the approximate number of reproducing bacteria in a sample, it would best to use __________. a fluorescent viability stain a Gram stain a fluorescent nucleic acid stain green fluorescent protein reporter genes

a fluorescent viability stain

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

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 exactly equal amounts of 34S and 32S. an isotope composition similar to igneous rocks. an isotope composition similar to marine sulfate, which is enriched in 34S. an isotope composition similar to marine mud, which is depleted in 34S.

an isotope composition similar to igneous rocks.

You would like to determine the rate of production of carbon dioxide in a specific microbial habitat. How could you do this without growing the microorganisms in the lab? by using radioisotope-labeled carbon dioxide by using radiolabeled DNA by using radiolabeled methane by using a microsensor

by using a microsensor

Which molecular method allows for the detection of a specific organism within a diverse microbial community? enrichment techniques viability staining fluorescent in situ hybridization fluorescent DNA staining using DAPI

fluorescent DNA staining using DAPI

What technique(s) can be used to characterize the phylogenetic composition of a microbial community without culturing any of the members? fluorescent in situ hybridization stable isotope techniques green fluorescent protein tagging radioisotope experiments

fluorescent in situ hybridization

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

function or gene expression / gene presence

Microarrays are useful for assessing enzyme activity. gene expression and the presence of specific rRNA sequences. the presence of specific rRNA sequences. gene expression.

gene expression and the presence of specific rRNA sequences.

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

genes / organisms themselves

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

genetic and functional diversity of microorganisms in the habitat under study

Culture-independent approaches avoid issues associated with next generation sequencing. conflating phylogenetic and functional diversity. growing organisms in the lab. detecting very rare phylotype

growing organisms in the lab.

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

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

The phylogenetic analysis of complex microbial communities often targets small subunit (SSU) ribosomal RNA genes. This is because rRNA is found in all organisms and __________. is highly conserved over evolutionary time has more genes than mRNA is easier to extract from samples is made by cells only at certain times

is highly conserved over evolutionary time

Select the option that lists the steps necessary for PCR microbial community analysis in the correct order. microbial sample collection; DNA extraction; PCR of target genes; sorting by electrophoresis; analysis microbial sample collection; PCR of target genes; DNA extraction; sorting by electrophoresis; analysis microbial sample collection; sorting by electrophoresis; analysis; DNA extraction; PCR of target genes PCR of target genes; microbial sample collection; DNA extraction; sorting by electrophoresis; analysis

microbial sample collection; DNA extraction; PCR of target genes; sorting by electrophoresis; analysis

Which technique would be used to estimate the concentration of naturally occurring Escherichia coli in a wastewater sample? most probable number (MPN) method laser tweezers method agar dilution tube method cell tagging using GFP method

most probable number (MPN) method

The best choice for estimating the viable cell number of a water sample would be the __________. most probable number method streak plating method spectrophotometric method agar dilution tube method

most probable number method

Microarrays that have been designed to screen samples for specific groups of bacteria are called __________. phylochips biochips microchips phytochips

phylochips

Genes that change over evolutionary time as organisms diverge are called orthologs. Organisms with identical or very similar orthologous genes belong to the same __________. genotype ribotype phylotype phenotype

phylotype

Metagenomics involves the analysis of a microbial community by __________. sequencing all of the community RNA in an environment sampling and sequencing all of the genes in an environment generating a complete sequence of the genomes of all of the organisms in an environment generating a phylogenetic tree based on all of the versions of a gene in an environment

sampling and sequencing all of the genes in an environment