Bacterial classification

• What are the aims of studying bacterial classification?

  To differentiate between Linnaean models and modern phylogenetics, understand taxonomy and phylogeny, and more.

  
• What is taxonomy?

  Taxonomy is classification based on shared characteristics.
• What does phylogeny measure?

  Phylogeny measures the evolutionary relationships between organisms.
• What are the steps in the taxonomic classification of microbes?

  1. Classification: Ordering organisms into groups based on shared properties.
  2. Nomenclature: Naming the classified organisms.
  3. Identification: Obtaining data on properties of an unknown organism.
• Who is considered the founder of modern taxonomy?

  Carl Linnaeus
• What traditional properties are used in the classification of bacteria?

  Microscopy/morphology, response to oxygen, mode of energy synthesis, and biochemical tests.
• What are molecular and genetic methods used for in bacterial classification?

  To choose appropriate molecular markers, amplify and sequence genes, and create evolutionary models.
• What is the basis of phylogeny?

  All living things have genes that mutate randomly, leading to evolutionary divergence.
• What are extremophiles?

  Organisms that thrive in extreme environmental conditions.
• What are methanogens?

  A type of archaea that produces methane anaerobically.
• What is the significance of the GC content in DNA/RNA?

  It represents the percentage of nitrogenous bases that are guanine and cytosine.
• What are the classifications within proteobacteria?

  • Gram positives (including mycoplasmas)
  • High G + C (actinomycetes, mycobacteria)
  • Low G + C (bacillus, clostridia)
• What is biovar in sub-species classification?

  A biochemical or physiological variant of a species.
• What is the difference between genotypic and phenotypic classification?

  Genotypic classification is based on genetic similarities, while phenotypic classification is based on physical and metabolic features.
• What is chemotaxonomic classification?

  A phenotypic classification that measures biochemical composition similarities among organisms.
• What are aerobes?

  Organisms that thrive in the presence of oxygen.
• What is the urease test used for?

  To determine if bacteria possess the urease enzyme, indicated by a color change in the media.
• What does the catalase test indicate?

  It indicates whether microbes can oxidize a test reagent, producing a blue/purple byproduct.
• What are the benefits of genotypic and phenotypic classification systems?

  Benefits of genotypic:

  • Reveals related taxonomic groups.

  Benefits of phenotypic:

  • Shows the time of species divergence.
• Why was there resistance to Woese's proposal of reclassifying Archaea as a separate domain?

  Due to the similarities and differences between Archaea and Bacteria, which made differentiation challenging.
• What are the similarities and differences between bacteria and archaea?

  Similarities:

  • Shape, size, and microscopic appearance.

  Differences:

  • Archaea lack peptidoglycan and may have different cell wall structures.
• How do archaea and bacteria multiply?

  Both multiply by binary fission and may move via flagella if motile.
• What type of ribosome do archaea have?

  Archaea have a different 70S ribosome compared to bacteria.
• How do archaea's genes compare to those of bacteria?

  Archaea's genes are more similar to eukaryotes than to bacteria.