Intro to Bacteriology

• What is the primary function of the bacterial cell wall?


  It maintains cell shape and provides protection
• What are the different shapes of bacterial cells?

  • Coccus (sphere)
  • Bacillus (rod)
  • Spiral
• How does the arrangement of bacterial cells assist in identification?


  Different arrangements indicate specific bacterial types
• What does "Coccus" refer to in bacterial classification?


  A spherical shape
• What does "Staphyl" indicate in bacterial arrangement?


  A grape-like arrangement
• What does "Strepto" refer to in bacterial arrangement?


  A chain-like arrangement
• What is the primary structural component of bacterial cell walls?

  Peptidoglycan
• What role do penicillin-binding proteins play in bacterial cell walls?


  They assemble peptidoglycan
• How do beta-lactam antibiotics affect bacterial cells?


  They block the activity of penicillin-binding proteins
• What are the functions of the inner cytoplasmic membrane in bacteria?


  • Acts as a permeability barrier
  • Serves as a protein anchor
  • Functions as a site of energy conservation
• What additional membrane do gram-negative bacteria possess?


  An outer lipid membrane containing LPS
• Why are gram-negative bacteria more impermeable to antibiotics?


  Due to the presence of the outer lipid membrane
• What color do gram-positive bacteria stain?


  Purple
• What color do gram-negative bacteria stain?


  Pink
• What is unique about acid-fast bacteria like Mycobacterium spp.?


  They resist decolorization due to their cell wall components
• What is the Ziehl-Neelsen stain used for?


  To stain acid-fast bacteria
• What are the steps of the Gram staining process?


  1. Smear colony and distilled water on slide
  2. Apply crystal violet
  3. Rinse off crystal violet and apply iodine
  4. Use acetone as an alcohol destain
  5. Use Safranin stain for gram-negative bacteria
• What are the functions of capsules and S-layers in bacteria?


  • Protect against desiccation
  • Help evade host defenses
  • Affect diffusion of complement and antibiotics
• How do S-layers assist bacteria in host interactions?


  They avoid host defenses and adhere to host cell surfaces
• What are flagella in bacteria?


  Filamentous protein organelles that drive bacteria towards stimuli
• How do flagella contribute to bacterial movement?


  They use ATP hydrolysis to drive bacteria towards positive stimuli or away from negative factors
• What is chemotaxis in bacteria?


  Movement towards positive stimuli or away from negative factors
• How can flagella be arranged on bacteria?


  At one end or around the entire surface of the bacterium
• What are fimbriae or pili?


  Hair-like adhesions that bind bacteria to host cell receptors
• What role do fimbriae play in bacterial conjugation?


  They are involved in the transfer of genetic material between bacteria
• What is the lipid A component of LPS?


  An important microbial-associated molecular pattern recognized by the immune system
• Which receptor recognizes lipid A in the innate immune system?

  Toll-like receptor 4 (TLR4)
• What is bacterial sporulation?


  A response to nutrient limitation or stress that produces dormant spores
• What are the characteristics of bacterial spores?


  They are dormant structures that resist adverse conditions
• What factors influence bacterial growth?


  Nutrients, temperature, atmosphere, pH, and ion concentrations
• What type of nutrition do most bacteria require?


  Most bacteria are heterotrophic and require organic substrates
• How do bacteria vary in their temperature tolerance?


  Some bacteria grow at extremes while others adapt to specific animal host temperatures
• What are the three categories of bacteria based on oxygen requirements?

  Aerobes, anaerobes, and facultative (an)aerobes
• What is the optimal pH for most bacteria?


  Neutral pH
• What are the lifestyles of bacteria in relation to host cells?


  Most are extracellular, while some can be facultative or obligatory intracellular
• How do facultative intracellular bacteria behave?


  They can survive outside host cells but can also infect and multiply inside
• What is the replication requirement for obligatory intracellular bacteria?


  They must replicate in eukaryotic cells
• How do bacteria multiply?


  By binary fission with logarithmic growth
• What happens during binary fission in bacteria?


  New cell membrane and wall form, chromosome duplicates, and a septum splits the cell
• How does the growth rate of bacteria relate to infections?


  Growth rate is related to the type of infection and the host's ability to eliminate bacteria