Deck 29: Methods in Microbial Ecology

Question 1

The fact that certain nucleotide templates are more readily amplified than others is termed _______.

A)multiplex PCR
B)analytical PCR
C)real-time PCR
D)PCR bias

Answer 1

D

Question 2

When doing SSU (small subunit ribosomal RNA)of a mixed population of microbes from an environmental sample,specific _______ are identified.

A)phenotypes
B)phylotypes
C)genotypes
D)unknown microbes

Answer 2

B

Question 3

A technique used to quantify specific types of microbes in natural samples,enrichment cultures,and food or water samples is known as the _______ ________ _______ technique.

Answer 3

most probable number

Question 4

It is generally agreed that SSU (small subunit ribosomal RNA)analysis is a technique that is well suited to identifying species present in a given community.

Question 5

The fact that cells of genetically uniform population do not have similar phenotypic attributes is called ______ heterogeneity.

A)dissimilar
B)population
C)quorum
D)epigenetic

Question 6

The use of modern molecular techniques has provided a mechanism for growing the microorganisms previously referred to as unculturable.

Question 7

When PCR amplification of SSU (small subunit ribosomal RNA)yields a population of different PCR products of about the same molecular weight,these fragments can be separated for further analysis by ______.

A)isoelectric focusing
B)size exclusion chromatography
C)denaturing gradient gel electrophoresis
D)DNA hybridization

Question 8

Optical tweezers can be used to _______.

A)study nucleic acids recovered from individual cells
B)help dissect individual microorganisms
C)remove structures from the surface of cells
D)All of the choices are correct.

Question 9

Which of the following is microscopy in which the microscope is fitted with light filters that enable the excitation of the specimen with a specific wavelength?

A)Epifluorescence microscopy
B)Electron microscopy
C)Bright-field microscopy
D)Dark-field microscopy

Question 10

_______ _______ arrays are used to assess the diversity of a microbial population.

Question 11

Phylogenetic oligonucleotide arrays (POAs)contain rRNA sequences as probes and are used as a means to detect complementary rRNA sequences from the environment.

Question 12

Determining the functional nature of a microbial community by analysis of bulk DNA samples extracted from environmental samples may be misleading for all of the following reasons EXCEPT

A)DNA is of little use in identifying unknown microbes.
B)some of the DNA recovered may be from non-living organisms.
C)some of the DNA may be from non-functional entities such as spores.
D)the DNA obtained can depend on the extraction method used.

Question 13

In the microdroplet culture method,cells from mixed assemblages are encapsulated in a gel matrix.The matrix is then emulsified to generate gel "microdroplets"; each microdroplet contains a mixture of cells.

Question 14

_______ culture are pure cultures,consisting of a single species.

Question 15

Recent evidence suggests that most microbial communities have many individuals representing at least ______ taxa.

A)1,000
B)100,000
C)10,000,000
D)1,000,000,000

Question 16

When fluorescently labeled oligonucleotides that are known to be specific to the microbe of interest are used to label natural samples,the technique is known as ______.

A)polymerase chain reaction (FISH)
B)fluorescent in situ hybridization (FISH)
C)epifluorescence microscopy
D)gel electrophoresis

Question 17

The level of specific mRNA,and therefore the expression of a given gene in a particular ecosystem,can be evaluated in the environment using in situ reverse transcriptase (ISRT)-FISH.

Question 18

________ culture techniques are based on the expansion of the microenvironment to allow abundant growth of a microorganism formerly restricted to a small ecological niche.

Question 19

The discrepancy between the number of microbial cells observed by microscopic examination and the number of colonies that can be cultivated from the same natural sample may be due to ______.

A)nonviable organisms
B)incorrect culture conditions
C)microbial motility
D)nonviable organisms and incorrect culture conditions

Question 20

What percentage of microbes have been cultured in the laboratory?

A)1%
B)10%
C)20%
D)30%

Question 21

__________ techniques are based on recreating a microenvironment in the laboratory to promote the growth of a microorganism formerly restricted to a small ecological niche.

A)Enrichment culture
B)Fastidious growth
C)PCR
D)Community growth

Question 22

In situ mRNA techniques are powerful and can be run at almost any time,in any condition because bacterial mRNAs are so stable.

Question 23

Microbial ecologists seek to understand how microbes drive and respond to the biogeochemical cycles that are essential for life on Earth.However,at this time it is only possible to make any concrete connections,identifications,or measurements about the abiotic flux of nutrients rather than the interactions between microbes that make these fluxes possible.

Question 24

The goal of _______ is to identify each protein present in a given microenvironment at the time of sampling.

A)metagenomics
B)metaproteomics
C)both metagenomics and metaproteomics
D)None of the choices are correct.

Question 25

________ microbes are used to measure oxygen availability,UV radiation dose,pollutant or toxic chemical effects,and stress.

Question 26

Because so few bacteria can be grown easily in culture,but all of them contain DNA,molecular techniques like PCR and SSU rRNA are used to be able to identify and quantify microorganisms as a "census" for diversity.

Question 27

The technique known as content,DNA sequence,and chemical gradient.Hence,similar fragments can be separated and identified.

Question 28

In _______ _______,cells are tagged with a fluorescent dye and injected into a flowing,progressively narrowing stream of fluid,forcing one cell at a time through a laser beam that scatters its fluorescence to a detector.
or
or

Question 29

Which of the following samples of microbial communities would be best suited for study by microelectrode experiments?

A)Striated microbial mats
B)10 gallons of seawater
C)Sample sorted by optical tweezers
D)During infection in a human patient

Question 30

In a .

Question 31

The technique known as _______ _______ _______ can be used to examine nutrient cycling in microbial communities as well as identify the microbes taking up the element of interest.
or
or
or

Question 32

When MAR is combined with FISH,one can analyze the phylogenetic identity and the specific substrate uptake patterns of microbes of interest at the level of a single cell in complex microbial communities.

Question 33

The reporter gene most commonly used to monitor changes in the physical microenvironment for a single microorganism is the ______.

A)green fluorescence protein gene
B)luciferase gene
C)beta-galactosidase gene
D)RecA protein gene

Question 34

In two-dimensional nano-liquid chromatography,a complex mixture of peptides is separated first by charge and then by solubility.

Question 35

While there are many uses for flow cytometry,a powerful addition to this technique is the ability to further sort,count,and collect individual fluorescent cells,known as fluorescence activated cell sorting (FACS).

Question 36

Stable isotope analysis to indicate whether or not certain elements have been processed by an organism is based on the observation that

A)microbes have no preference as regards heavy versus light isotopes.
B)microbes generally prefer using the heavier of two stable isotopes.
C)microbes generally prefer using the lighter of two stable isotopes.
D)None of the choices are correct.

Question 37

Suppose a microbiologist wanted to identify the microbe responsible for a specific metabolic activity.To simultaneously assess metabolic activity and phylogenetic identity,the best technique would be _______.

A)microautoradiography with fluorescent in situ hybridization (MAR-FISH)
B)metatranscriptomics
C)isotope fractionation
D)optical tweezers with microelectodes