Bacterial Classification Flashcards

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Questions and Answers

What are considered to be the three parts of Taxonomy?

classification, identification, nomenclature

What is the orderly arrangement of organisms into taxonomic groups on the basis of their similarities and relationships?

classification

What is the short name for taxonomic groups?

taxon (singular), taxa (plural)

What is the process of determining whether an isolate belongs to one of the established, named taxa or represents a previously unidentified species?

identification Signup and view all the answers

Identification is the practical use of classification criteria to?

All of the above Signup and view all the answers

What is the assignment of names to the various taxa according to international rules?

nomenclature Signup and view all the answers

What characteristics are used to identify and classify bacteria?

phenotypic characteristics, analytic characteristics, genotypic characteristics Signup and view all the answers

What are classic phenotypic characteristics?

microscopic morphologies, macroscopic morphologies, growth and biochemical characteristics Signup and view all the answers

What phenotypic methods help with classification?

biotyping, serotyping, antibiogram patterns analysis, phage typing Signup and view all the answers

What are classic analytic characteristics?

cell wall fatty acids, whole cell lipids, whole cell proteins, whole cell enzymes Signup and view all the answers

What are classic genotypic characteristics?

genome size, guanine plus cytosine ratio Signup and view all the answers

What are the genotypic techniques which help with classification?

DNA hybridization, nucleic acid sequence analysis, plasmid analysis, ribotyping, chromosomal DNA fragment analysis Signup and view all the answers

What are the ultimate goals of identifying and classifying bacteria?

collect as much information as possible, evaluate all results in relation to each other, draw useful conclusions Signup and view all the answers

List the characteristics pertaining to the macroscopic appearance of bacteria colonies which can be used to identify bacteria.

size and shape of colonies, elevation and appearance of the edge of the colonies, optical characteristics, pigmentation of the colonies, haemolytic properties, swarm properties, autofluorescence under long-wavelength ultraviolet light Signup and view all the answers

What is a 'colony' in terms of microbiology?

collection of bacterial (or fungal) cells of a given species, growing in a single site, visible with the naked eye Signup and view all the answers

What is a cfu?

Colony Forming Unit Signup and view all the answers

Bacterial colonies originate from a grouping of cells that proliferate rapidly.

False Signup and view all the answers

List the different colony forms.

circular, irregular, filamentous, rhizoid Signup and view all the answers

List the different colony elevations.

raised, convex, flat, umbonate, cateriform Signup and view all the answers

List the different colony margins.

entire, undulate, filiform, curled, lobate Signup and view all the answers

The most common methods that are still used to identify bacteria consist of measuring the presence or absence of specific ______________.

biochemical markers Signup and view all the answers

What biochemical tests are used routinely for many types of bacteria?

oxidase, nitrate reduction, amino acid degrading enzymes, fermentation/utilization of carbohydrates Signup and view all the answers

Certain biochemical tests are restricted to single families; which families are checked with the following tests: coagulase test and pyrrolidonyl arylamidase test?

Coagulase: staphylococci; Pyrrolidonyl arylamidase: Gram-positive cocci Signup and view all the answers

Serotyping is a definitive typing method which can be used to identify organisms that are...?

inert in biochemical testing, difficult or impossible to grow, associated with specific disease syndromes, need to be identified rapidly Signup and view all the answers

Name the letters which correspond and represent the following antigens: cell wall, flagellar, capsular.

C (cell wall), H (flagellar), K (capsular) Signup and view all the answers

Study Notes

Taxonomy Basics

Taxonomy consists of three main components: classification, identification, and nomenclature.
Classification is the systematic arrangement of organisms into groups based on similarities and relationships.
Taxon is the singular term for a taxonomic group, while taxa is the plural form.
Identification involves determining if an organism belongs to an established taxon or if it represents a new species.

Identification Process

The identification process practically applies classification criteria to differentiate organisms, verify strains, and isolate disease-causing organisms.

Nomenclature

Nomenclature refers to the assignment of names to various taxa following established international rules.

Characteristics for Classification

Bacteria are classified using phenotypic, analytic, and genotypic characteristics.
Phenotypic characteristics include microscopic morphologies, macroscopic morphologies, and growth/biochemical features.

Phenotypic Methods

Common phenotypic classification methods include biotyping, serotyping, antibiogram patterns, and phage typing.

Analytic and Genotypic Characteristics

Analytic traits consist of cell wall fatty acids, whole cell lipids, proteins, and enzymes.
Genotypic characteristics involve genome size and the guanine plus cytosine ratio.
Genotypic techniques for classification include DNA hybridization, nucleic acid sequence analysis, plasmid analysis, ribotyping, and chromosomal DNA fragment analysis.

Goals of Classification

The ultimate aims are to gather information, evaluate results relative to one another, and draw meaningful conclusions.

Macroscopic Appearance of Bacterial Colonies

Characteristics to identify bacteria from colony appearance include size, shape, elevation, edge appearance, optical features, pigmentation, haemolytic properties, swarm behavior, and autofluorescence.

Defining Colonies

A colony is a visible collection of bacterial or fungal cells of a single species growing on solid medium.
Colony Forming Unit (cfu) is a term used to denote the number of viable cells in a sample.

Colony Formation

Bacterial colonies originate from a single bacterial or fungal cell, not from groups of cells proliferating together.

Colony Types

Various colony forms include circular, irregular, filamentous, and rhizoid shapes.
Elevations can be categorized as raised, convex, flat, umbonate, or cateriform.
Colony margins can be entire, undulate, filiform, curled, or lobate.

Biochemical Markers

The identification of bacteria often relies on biochemical markers, which are measurable traits indicating the presence or absence of specific substances.

Routine Biochemical Tests

Common biochemical tests include oxidase, nitrate reduction, amino acid degrading enzymes, and carbohydrate fermentation/utilization.

Specific Biochemical Tests

Specific tests like the coagulase test are used for staphylococci, while the pyrrolidonyl arylamidase test is employed for Gram-positive cocci.

Serotyping

Serotyping is a reliable method for identifying organisms that are inert in biochemical testing, hard to culture, associated with specific diseases, or require rapid identification.

Antigen Representation

Different antigens are represented by specific letters: cell wall (O), flagellar (H), and capsular (K).

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Description

Test your knowledge on the basic principles of bacterial classification and morphology with these informative flashcards. Learn about taxonomy including classification, identification, and nomenclature as well as the arrangement of organisms into taxonomic groups.