Micro Ch 6,11

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Micro Ch 6,11
2012-09-10 11:31:45
microbiology virology

Okstate Micro 2013
Show Answers:

  1. What is a virus?
    • An obligatory intracellular parasite
    • all have a protein coat
    • target host cell receptors
  2. What is the basic structure determining shape?
    • the capsid
    • encoded for in the viral genome
    • it's composed of repeated protein subunits, minimizing the number of genes requires.
    • two main capsid forms: symmetrical and asymmetrical
  3. What is the virus protein coat?
  4. What determines host range?
    • available receptors 
    • cellular factors
    • types of hosts a virus can infect
  5. Symmetrical vs Asymmetrical Viruses
    • symmetrical: filamentous or icosohedral 
    • asymmetrical: T4 bacteriophages, poxviruses
  6. What occurs in the lytic cycle?
    • bacteriphage replicates quickly, killing the host
    • the host cell explodes, releasing the bacteria
  7. What happens in the lysogenic cycle?
    • bacteriphage is quiescent
    • integrates into cell chromosome as PROPHAGE
    • can reactivate to become lytic
  8. What is tranduction?
    the mechanism by which DNA moves from one bacterium to another (when a virus takes some of the host DNA with it)
  9. What is prophage?
  10. What are the viral genome types?
    • DNA/RNA
    • Single/double stranded
    • linear/circular
  11. What are the three main viral genomes?
    • DNA viruses 
    • RNA viruses
    • Retroviruses
  12. What are the steps of the animal virus life cycle? (in order)
    • Attachment
    • Penetration
    • Uncoating
    • Biosynthesis
    • Maturation 
    • Release
  13. What is the DNA life cycle?
    • virus enters cell and travels to nucleoid before uncoating
    • Uses host polymerase to create RNA template then replicate
  14. What is the RNA life cycle?
    • RNA genome inserted into host cell
    • viral genome replicated using RNA dependant RNA polymerase
    • lyses host
  15. What is the retrovirus life cyle?
    • Binds to host then uncoats envelope, sending the capsid into host.
    • Uses ITS OWN reverse transcriptase, which creates a DNA copy of the original RNA genome.
    • DNA copy is inserted into host genome.
    • buds off host, creating envelope