24 Questions
What is the science of classification of organisms that hopes to show relationships among organisms?
Taxonomy
What is the main difference between classification and identification?
Classification is a broader term, while identification is more specific
What is the name of the technique used to determine the susceptibility of bacterial strains to certain phages or bacterial viruses?
Phage Typing
What is the term for the evolutionary relationships and history among organisms?
Phylogeny
Which of the following is NOT one of the 5 kingdoms based on nutrient procurement?
Eukarya
What is the term for the study of the structure, behavior, and evolution of organisms?
Systematics
What is the term for the proportion of guanine and cytosine bases in DNA?
GC content
Which domain includes plants, animals, fungi, and protists?
Eukarya
What is the primary purpose of biochemical tests in bacterial identification?
To determine the nutritional and physiological interaction of the organism with its environment
What is the function of differential staining in bacterial identification?
To distinguish between different types of bacteria
What is the purpose of a dichotomous key in bacterial identification?
To identify eukaryotes
What is the significance of highly conserved sequences in bacterial genetic material?
They are found in all bacteria
What is the purpose of the International Code for the Nomenclature of Bacteria?
To set out the rules for bacterial nomenclature
What is the purpose of a clinical microbiology lab report form?
To report the results of microbiological tests
What is the significance of the genus and species names in bacterial nomenclature?
The first name characterizes the genus and the second the species
What is the purpose of family names in bacterial nomenclature?
To end in -aceae
What is the first step in the classification of bacteria?
Grouping them into a hierarchic system based on phenotypic characteristics
What is the basic unit of classification in bacteria?
Species
How are family names of bacteria typically denoted?
They end in -aceae
What is the role of chemical characteristics in bacterial classification?
It is growing in importance
What is the significance of DNA-DNA hybrids in bacterial classification?
They provide information on the similarity of different bacteria
What is the significance of GC content in bacterial classification?
It provides information on the evolutionary relationships of bacteria
What is the significance of the sequence analysis of 16S/23S rRNA or rDNA in bacterial classification?
It provides information on the phylogenetic relationships of bacteria
What is the main reason for the classification of bacteria being based on phenotypic characteristics?
Because little is known about the phylogenetic relationships of bacteria
Study Notes
Taxonomy and Classification
- Taxonomy includes two disciplines: classification and nomenclature
- Classification is based on phenotypic characteristics (morphological, physiological, and chemical)
- The basic unit of classification is the species
- Similar and related species are classified in a single genus, and related genera are placed in a single family
Classification of Bacteria
- Bacteria are grouped in the domain Bacteria
- Within the domain, bacteria are further broken down into taxonomic groups (taxa) based on relationships and phylogenetic facts
- Classification is often based on similarities among phenotypic characteristics (phenetic relationships)
- Morphological, physiological (metabolic), and chemical characteristics are used in classification
Morphological Characteristics
- Microscopic morphology: cell shape, size, arrangement, staining, capsule, spore morphology
- Colonial morphology: colonial appearance, color, shape, texture, margin, elevation, etc.
Biochemical Tests
- Fermentation/oxidation of carbohydrates
- Enzyme activities
- Metabolism of organic acids, lipids, proteins, and amino acids
- pH or redox range of growth
- Tolerance of chemical agents
Nomenclature
- The rules of bacterial nomenclature are set out in the International Code for the Nomenclature of Bacteria
- A species is designated with two Latinized names, the first of which characterizes the genus and the second the species
- Family names always end in -aceae
- Taxonomic names approved by the International Committee of Systematic Bacteriology are considered official
Hierarchy of Taxonomic Ranks
- Species
- Genus
- Family
- Order
- Class
- Division
- Phylum
- Kingdom
- Domain
Phylogeny and Systematics
- Shows evolutionary relationships and history among organisms
- Uses rRNA sequencing or other sequence information to identify organisms
- Goal is to identify all organisms by 2025
5 Kingdoms of Nutrient Procurement
- Plantae: multicellular photoautotrophs
- Animalia: ingestive
- Fungi: absorptive
- Protozoa: mostly single-celled
- Prokaryotes: bacteria and archaea
This quiz covers the principles of taxonomy, classification, and nomenclature in microbiology, including the hierarchical system of classification based on phenotypic characteristics.
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