Bacterial Classification and Nomenclature

Bacterial Classification and Nomenclature — Quiz

25 multiple‑choice questions. Submit to see correct/incorrect highlighting and your score.

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1) Which binomial is correctly formatted?

Escherichia Coli Escherichia coli ESCHERICHIA coli E. Coli

2) Which domain includes the true bacteria?

Archaea Bacteria Eukarya Protista

3) What is the primary purpose of the Gram stain?

Differentiate bacteria by cell wall structure Visualize capsules only Measure bacterial motility Determine oxygen requirements

4) Which bacteria retain crystal violet after decolorization?

Gram-positive Gram-negative Acid-fast Spirochetes

5) After first mention, which is an acceptable abbreviation of Escherichia coli?

Esch. coli E. c. E. coli E. Coli

6) The suffix “-aceae” denotes which taxonomic rank in bacteria?

Order Family Class Genus

7) Which reference is standard for bacterial classification and identification?

Gray’s Anatomy Dorland’s Medical Dictionary Bergey’s Manual of Systematic Bacteriology ICD‑10

8) Which metric is commonly used for genomic species delimitation in bacteriology?

G+C content alone Colony pigment color Average Nucleotide Identity (ANI) ~95% Cell size

9) Which code governs naming of prokaryotes (bacteria and archaea)?

ICZN ICN (Plants, Algae, Fungi) ICNP (International Code of Nomenclature of Prokaryotes) IUPAC

10) What is the role of a type strain in bacterial nomenclature?

It is the most virulent strain It is the first strain ever isolated It serves as the nomenclatural reference for the species It has the highest G+C content

11) The suffix “-ales” denotes which rank?

Order Family Class Genus

12) Which taxon names are italicized in standard bacteriological writing?

Genus and species names Family and order names Only species epithets No scientific names are italicized

13) Which is correctly written?

staphylococcus aureus Staphylococcus Aureus Staphylococcus aureus Staphylococcus aureus

14) Which gene is commonly used as a phylogenetic marker for bacteria?

18S rRNA gene 16S rRNA gene COI gene Hemoglobin gene

15) What does the designation “Candidatus” indicate?

A fully validated species name A synonym Provisional status for an uncultured or incompletely described taxon A pathogenic variant

16) What does “sp.” mean after a genus name (e.g., Pseudomonas sp.)?

A single unspecified species within the genus Multiple species in the genus A subspecies A strain designation

17) What is the correct abbreviation for the infraspecific rank “subspecies”?

ssp. subsp. subs. spb.

18) In bacteriology, a pathovar (pv.) indicates:

A genomic species A serological group A variant within a species defined by host range or pathogenicity (often in plant pathogens) A family-level clade

19) For valid publication of a new bacterial species under the ICNP, which is required?

Posting the name on a lab website Publishing only in any peer‑reviewed journal without a type strain Designation of a type strain and valid publication/validation (e.g., in IJSEM or Validation Lists) Approval by IUPAC

20) LPSN is best described as:

A protein database List of Prokaryotic names with Standing in Nomenclature A clinical guideline A sequencing platform

21) Choose the correct hierarchy (highest to lowest):

Domain > Class > Phylum > Order > Family > Genus > Species Domain > Phylum > Class > Order > Family > Genus > Species Domain > Phylum > Order > Class > Family > Genus > Species Phylum > Domain > Class > Order > Family > Genus > Species

22) Which statement about Gram‑negative bacteria is correct?

They lack an outer membrane They retain crystal violet during Gram staining They possess an outer membrane containing lipopolysaccharide (LPS) They have a thicker peptidoglycan layer than Gram‑positives

23) For adjectival specific epithets, agreement must be with the genus’s:

Ecological niche Grammatical gender Discovery date Genome size

24) What does a designation like “ATCC 25922” indicate?

A family name A serotype A specific strain preserved in a culture collection A subspecies

25) Which suffix–rank pairing is incorrect for bacteria?

Order — -ales Family — -aceae Subfamily — -inae Family — -idae

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