MICROPARA FINALS

• What are the two groups of microbes under Protista?

  Prokaryotes and Eukaryotes
• Why is it important to note the differences between eukaryotic and bacterial cells?

  They account for disease pathogenesis

  
• What is the size range of bacteria?

  0.4 um to 2.0 um
• What are the functions of the bacterial capsule?

  • Prevents phagocytosis
  • Protects from bacteriophage
  • Provides energy and nutrition
  • Serves as a good antigen for identification
  • Used in vaccine preparation
• Which bacteria are known to have a capsule?

  Streptococcus pneumoniae
• What happens to capsules during repetitive in-vitro culture?

  They are lost
• What is an example of a bacteria that produces a protein capsule?

  Bacillus anthracis
• What is a microcapsule?

  Very thin capsule not seen by light microscopes
• What is a slime layer in bacteria?

  Outer covering easily washed off
• How can capsules be demonstrated in bacteria?

  • Best seen in pathological specimens
  • Lost on artificial culture media
• What is the cell wall of bacteria described as?

  A tough and rigid structure

  
• What percentage of the dry weight of bacteria does the cell wall weigh?

  20-25%
• What is peptidoglycan also known as?

  Murein or mucopeptide
• In which type of bacteria is peptidoglycan more abundant?

  Gram-positive bacteria

  
• What are the parts of peptidoglycan?

  1. Backbone of NAG and NAM
  2. Tetrapeptide side chain with D-alanine
  3. Pentapeptide cross-bridges
• What are the functions of the bacterial cell wall?

  • Provides rigidity and shape
  • Protects from the environment
  • Induces immune response
  • Attachment site for flagella

  
• How can the cell wall be demonstrated?

  Plasmolysis and differential staining
• How does the Gram-positive cell wall differ from the Gram-negative cell wall?

  It is at least 10 times thicker

  
• What is teichoic acid also called?

  Teichuronic acid
• What is the major permeability barrier in Gram-negative bacteria?

  Outer cytoplasmic membrane
• What are the components of lipopolysaccharide?

  1. Outer O antigen
  2. Polysaccharide core
  3. Inner lipid A region
• What is the significance of the outer O antigen in lipopolysaccharides?

  It is used for serological diagnosis
• What is the chemical composition of acid-fast cell walls?

  Contains mycolic acid
• What is the process of spore formation in bacteria called?

  Sporulation
• What are the characteristics of spores formed by bacteria?

  • Highly resistant
  • Metabolically dormant
  • Resist extreme conditions
• What is the structure of the cytoplasmic membrane?

  A thin, elastic, semipermeable layer
• What is the function of the cytoplasmic membrane?

  Controls inflow and outflow of metabolites
• What are ribosomes composed of?

  rRNA and ribosomal proteins
• What is the Svedberg unit for bacterial ribosomes?

  7 s
• How does streptomycin affect bacteria?

  Interferes with bacterial metabolism at ribosomes
• What are intracytoplasmic inclusions in bacteria?

  • Sources of stored energy
  • May include volutin, lipid, polysaccharide, sulfur granules
• What are mesosomes in bacteria?

  Invaginations of the cytoplasmic membrane
• What is the function of flagella?

  Organ of locomotion
• What are the three major substructures of flagella?

  Filament, hook, and basal body
• What are the different patterns of flagella?

  • Monotrichous
  • Amphitrichous
  • Lophotrichous
  • Peritrichous
• What is the significance of flagella in bacteria?


  Used to identify various types of bacteria

  
• What is the process of sporulation in bacteria?

  • Formation of spores under favorable conditions
  • Mode of survival under adverse conditions
• What is the term for bacteria that can form spores?

  Sporulating bacteria
• What are the conditions that spores can resist?

  High temperatures, dryness, and UV radiation
• What are the characteristics of L forms in bacteria?

  • Produced by treatment with lytic enzymes
  • Can be unstable or stable