Microbiology

• What is the definition of a virus?

  A non-cellular particle made of genetic material
• Who studied filtered plant juices and discovered viruses?

  Beijerinck
• How do viruses compare in size to cells?

  Viruses are smaller than cells
• What tool is used to view viruses?

  Electron microscope
• What are the characteristics of viruses?

  • Nonliving structures
  • Noncellular
  • Protein coat called the capsid
  • Nucleic acid can be DNA or RNA
  • Reproduce only in host cell
• What additional features can some viruses have?

  • Protective envelope
  • Spikes for attachment to host cells
  • Specificity for host cells
• What are viral capsids made of?

  Individual protein subunits called capsomeres
• What are some examples of viral diseases?

  • Smallpox
  • Measles
  • Mononucleosis
  • Influenza
  • Colds
  • Warts
  • Ebola
  • Some cancers like leukemia
• What is a bacteriophage?

  A virus that infects bacteria
• What do T-phages infect?

  1. E. coli
• How do T-phages attach to host cells?

  Using six small spikes at the base of a contractile tail
• What are prions?

  Infectious proteins that alter normal proteins. They have no DNA or RNA
• What happens to normal proteins when they come into contact with prions?

  They convert into an alternate configuration and become prion proteins
• What are the effects of prion diseases?

  • Form insoluble deposits in the brain
  • Example: Mad cow disease (BSE)
• What is the stability of prions?

  • Practically indestructible
  • Inactivation requires autoclaving in alkali solution
• What are the symptoms of Creutzfeldt-Jakob Disease (CJD)?

  Lack of coordination and staggering
• What is the outcome of CJD?

  Death within one year of symptom onset
• What is the difference between CJD and vCJD?

  Both produce transmissible spongiform encephalopathies
• Are viruses living or non-living?

  Both, depending on the definition of life
• What is the role of the capsid in viruses?

  Protects genetic material and prevents infection
• How do prions propagate?

  By converting normal proteins into abnormal ones
• What is the mechanism of prion-induced neurodegeneration?

  Disruption of cell membranes and aggregation
• What are the types of prion diseases?

  • Creutzfeldt-Jakob Disease (CJD)
  • Variant CJD (vCJD)
  • Bovine spongiform encephalopathy (BSE)
• What are the two main groups of prokaryotic microbes?

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

  No nuclear membrane
• Where is DNA located in prokaryotic cells?

  In the cytoplasm
• What structure do bacteria have that provides rigidity?

  Rigid cell wall
• How do bacteria typically exist?

  Usually unicellular
• What is a characteristic of some multicellular prokaryotes?

  They have specialized cells
• What is the shape of Escherichia coli?

  Rod-shaped
• What are the two common shapes of bacteria?

  Rods and spherical
• What is the term for spherical bacteria?

  Coccus/cocci
• What is the purpose of classification in microbiology?

  To organize and identify organisms
• What are the methods used for bacterial classification?

  • Colony morphology
  • Growth characteristics
  • Microscopy
  • Molecular tests
• What is the process of DNA replication in bacteria?

  Bidirectional DNA replication
• What type of environments do Archaea inhabit?

  Extreme environments
• What is a characteristic of thermophiles?

  Live at high temperatures
• Where are psychrophiles commonly found?

  In Antarctica
• What is one application of Archaea in industry?

  Enzymes in washing powders
• What roles do microbes play in the environment?

  • Essential to nutrient cycles
  • Affect every aspect of life
  • Act as tiny chemical processors