MT2 > Classification of Infectious Agents Flashcards

1
Q

Define Taxonomy.

A

The science of classifying organisms.

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2
Q

Define Phylogeny (systematics).

A

The study of the evolutionary history of organisms.

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3
Q

Who came up with the binomial naming convention we use today? When?

A

Carl Linnaeus in 1735.

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4
Q

What were the two original kingdoms identified by Linnaeus?

A

Plantae and Animalia.

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5
Q

What domains were eventually proposed by Woese in 1978 and universally adopted?

A

Eukarya, Archaea, Bacteria.

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6
Q

Which domains of organisms have membrane lipids which are composed of straight carbon chains attached to glycerol by an ester linkage?

A

Bacteria and Eukarya.

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7
Q

Which domains of organisms have membrane lipids which are composed of branched carbon chains attached to glycerol by an ether linkage?

A

Archaea.

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8
Q

What is the purpose of a phylogenetic tree?

A

To group organisms according to their evolution from a common ancestor.

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9
Q

With regards to prokaryotic species, what is a culture?

A

A colony of bacteria grown in laboratory media.

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10
Q

With regards to prokaryotic species, what is a clone?

A

A population of cells derived from a single parent cell.

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11
Q

With regards to prokaryotic species, what is a strain?

A

Within a clone, a group of genetically different cells (may have diverged though mutation).

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12
Q

What are the common characteristics of Protista?

A

A catchall kingdom for variety of autotrophic and heterotrophic organisms.

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13
Q

What are the common characteristics of Fungi?

A

Chemoheterotrophic, unicellular or multicellular, cell wall of chitin, develop spores.

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14
Q

What are the common characteristics of Plantae?

A

Multicellular, cellulose cell walls, undergo photosynthesis.

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15
Q

What are the common characteristics of Animalia?

A

Multicellular, no cell walls, chemoheterotrophic.

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16
Q

What is a “viral species”?

A

Not a part of any domain, not composed of cells, non-living. A species consists of viruses with similar characteristics sharing an ecological niche.

17
Q

What differentiates classification and identification?

A

Classification: placing organisms in groups of related species
Identification: matching an unknown organism to a list of known organisms

18
Q

What information does Bergey’s Manual of Determinative Bacteriology provide?

A

Identification schemes for identifying bacteria and archaea.

19
Q

What information does the Approved Lists of Bacterial Names provide?

A

It lists bacterial species of known classification.

20
Q

What 3 major approaches can be used to identify microorganisms?

A
  1. Differentiate by morphology
  2. Differential staining
  3. Biochemical tests
21
Q

Under what circumstance should differential staining not be used to identify a microorganism?

A

When trying to identify a bacteria without a cell wall.

22
Q

What is meant by a “rapid identification method”?

A

A test which combines several biochemical tests into one, streamlining the identification process.

23
Q

Define “serology”.

A

The science that studies serum and immune responses in serum.

24
Q

What is the purpose of an antiserum? How does it work?

A

To identify an unknown bacterium by testing it in a solution of known antibodies.

25
Q

What is the purpose of a slide agglutination test? How does it work?

A

To identify an unknown bacterium by testing the agglutination of the bacteria in response to known antibodies.

26
Q

What is the purpose of serological testing in epidemiology?

A

To differentiate between species and strains within species when identifying an unknown microorganism.

27
Q

What is the purpose of an ELISA test in epidemiology? How does it work?

A

To identify an unknown bacterium by testing it in a microplate with many wells, each filled with a specific antibody and enzyme.

28
Q

What is the purpose of phage typing in epidemiology? How are the results observed?

A

To determine which phages a bacterium is susceptible to. On a plate, “plaques” appear where phages have lysed the bacterial cells.

29
Q

What is meant by FAME? Why is this of interest to epidemiologists?

A

Fatty Acid Methyl Esters. The FAME profile is constant and unique for a particular species of microorganism, and can be used for identification.

30
Q

How can we use flow cytometry to differentiate between bacterial species?

A

By observing differences in electrical conductivity or fluorescence between species.

31
Q

How does a fluorescence-activated cell sorter (FACS) organize cells?

A

A laser detects the fluorescently labelled cells, which are then given a positive charge by an electrode. These are then sorted by charge into positive or neutral collection tubes.

32
Q

How is DNA fingerprinting used in epidemiology?

A

By comparing digested fragments of DNA from different organisms we can see genetic similarities and differences.

33
Q

How are the unique fatty acid methyl esters (FAME) of a bacterium identified?

A

First with gas chromatography and then with a flame ionization detector.

34
Q

When might nucleic acid amplification tests (NAATs) be used?

A

When a microorganism cannot be cultured.

35
Q

What can nucleic acid hybridization be used to determine? How? What test is based on this principle?

A

The degree of relatedness of two organisms is shown by how well their DNA strands hybridize. Called a DNA chip or microarray.

36
Q

Define “ribotyping”.

A

Probing a bacterial genome with a 16S rRNA gene probe to identify it.

37
Q

How can fluorescence in-situ hybridization (FISH) be used in epidemiology?

A

To determine the identity, abundance, and relative activity of microorganisms in an environment.