Deck 27: Methods in Microbial Ecology

Question 1

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.

Answer 1

D

Question 2

The identification of more than one type of PCR product in a single reaction is called _______ PCR.

Answer 2

multiplex

Question 3

Counting the number of different genomes present by DNA analysis of an environmental sample is accomplished by

A) DNA reassociation.
B) hybridization probe analysis.
C) thermal melting point analysis.
D) G + C content analysis.

Answer 3

A

Question 4

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 5

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.

Question 6

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 7

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

Question 8

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

Question 9

What percentage of microbes have been cultured in the laboratory?

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

Question 10

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 11

________ 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 12

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

Question 13

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 14

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

Question 15

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 16

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 17

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 18

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

Question 19

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

Question 20

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 21

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

Question 22

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

Question 23

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 24

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

Question 25

Organized microbial systems consisting of layers of microbial cells associated with surfaces are called _________________.

Question 26

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

Question 27

Which of the following techniques uses PCR primers representing the different 16S rRNA genes of interest, enabling the detection of multiple SSU rRNA genes and thus multiple microbial genera?

A) fluorescent in situ hybridization (FISH)
B) hierarchical oligonucleotide primer extension (HOPE)
C) catalyzed reported deposition-FISH (CARD-FISH)
D) all of the choices

Question 28

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

Question 29

Thick, macroscopic biofilms are referred to as microbial ________.

Question 30

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.