prokaryotic microbes

• What are the two main groups of prokaryotic microbes?

  Bacteria and Archaea
• What is a characteristic of prokaryotic cells regarding their nucleus?

  No defined nucleus
• What type of ribosomes do prokaryotes have?

  70S ribosomes
• How do prokaryotes replicate?

  Via asexual reproduction
• What is the most common method of prokaryotic replication?

  Binary fission
• How can you measure the optical density of a bacterial culture?

  Using a spectrophotometer
• What does a higher cell density indicate in optical density measurements?

  More light is scattered
• What is the viable counting method for bacteria?

  1. Take a sample of bacterial culture
  2. Make dilution series
  3. Plate on agar plates
  4. Incubate overnight
  5. Count visible colonies
• What is a characteristic of colony morphology?

  Includes color, shape, and texture
• What are the energy sources for different types of microbes?

  • Phototrophs: sunlight
  • Chemotrophs: chemicals
  • Organotrophs: organic compounds
  • Lithotrophs: inorganic compounds
• What are the carbon sources for microbes?

  • Autotrophs: CO₂
  • Heterotrophs: organic compounds
• What type of prokaryotes are cyanobacteria?

  Photolithoautotrophs
• What does the term 'niche' refer to in microbiology?

  Environmental conditions for microbe replication
• What factors determine a microbe's niche?

  • Nutrient availability
  • Oxygen concentration
  • Temperature
  • pH
  • Light intensity
  • Radiation
  • Solute concentration
• What are extremophiles?

  Organisms that grow in harsh conditions
• What is the lifestyle of free-living microbes?

  Inhabit every type of environment
• What are the types of microbe-host interactions?

  • Pathogenic: host damaged
  • Mutualistic: both benefit
  • Commensal: one benefits, other unaffected
• What is the shape of rod-shaped bacteria?

  Bacilli
• What are the arrangements of bacterial cells?

  • Chains
  • Clusters
  • Pairs
• What is the function of the nucleoid in prokaryotic cells?

  Location of chromosome and proteins
• What are plasmids?

  Extrachromosomal DNA in bacteria
• What is peptidoglycan?

  A component of bacterial cell walls
• What are the two types of bacterial cell walls?

  • Gram-positive: thick peptidoglycan
  • Gram-negative: thin peptidoglycan and outer membrane
• What color do Gram-positive bacteria stain?

  Purple
• What color do Gram-negative bacteria stain?

  Pink or red
• What is the structure of peptidoglycan?

  Mesh-like polymer of sugars and peptides
• What is the role of teichoic acids in Gram-positive bacteria?

  Anchor cell wall to plasma membrane
• What is unique about the outer membrane of Gram-negative bacteria?

  It acts as a selective permeable barrier
• What are the three parts of lipopolysaccharide (LPS)?

  Lipid A, core polysaccharide, O side chain
• What is the importance of LPS in Gram-negative bacteria?

  Contributes to negative charge on cell surface
• What is the function of capsules in bacteria?

  Protect against phagocytosis and desiccation
• What are the functions of S layers in bacteria?

  • Protect from environmental stress
  • Maintain shape and rigidity
  • Promote adhesion to surfaces
• What is the function of flagella in bacteria?

  Motility and swarming behavior
• What type of shock is septic shock?

  Septic shock
• What is the outer membrane of Gram-negative bacteria characterized by?

  Selective permeability due to porin proteins
• What do porin proteins in the outer membrane allow?

  Free diffusion of small molecules
• What is the composition of a bacterial capsule?

  Usually composed of polysaccharides
• How is the capsule of bacteria described in terms of organization?

  Well organized and not easily removed
• What can be seen with a light microscope when using a capsule stain?

  The capsule of bacteria
• What protective advantages does a capsule provide to bacteria?

  Resistant to phagocytosis and desiccation