Microbiology 351 Exam 1 Flashcards - Set 7

  1. True/False: Viruses cannot infect all forms of life.
    False, all life-forms can be infected by viruses.
  2. Define a virus.
    Noncellular particle that must infect a host cell, where it reproduces.
  3. The virus particle, or _____, consists of nuclei acid (DNA or RNA) contained within a protective protein ______.
    virion, capsid
  4. Name the famous person: developed the first polio vaccine in 1952.
    Josan Salk
  5. Each species of virus infects a particular group of host species, or ____ _____.
    host range
  6. Small viruses commonly have a small genome, encoding under ____ genes.
    ten, the genes may overlap in sequence.
  7. Large viruses may have more than ____ genes.
    100, indeed, mimivirus encodes over 1,000 genes
  8. _____ are RNA molecules that infect plants.
    Viroids
  9. Viroids have no _____ _____.
    - Are replicated by _____ RNA polymerase.
    - Some have ______ ability.
    • - protein capsid
    • - host
    • - catalitic
  10. _____ are proteins that infect animals.
    Prions
  11. True/False: Prions have nucleic acid components.
    • False, they have none.
    • - Have an abnormal structure that alters the conformation of other normal proteins
  12. The viral ____ is composed of repeated subunits, which maximizes the capacity while minimizing the required number of genes.
    capsid
  13. The viral ____ packages the viral genome and elivers it into the host cell.
    capsid
  14. Icosahedral viruses are _____ and have 20 _____ triangular faces, exhibiting _____ symmetry.
    • - symmetrical
    • - identical
    • - rotational
  15. In some icosahedral viruses, the capsid is enclosed in an _______, formed from the cell membrane, which comes from the _____ cell.
    envelope, host
  16. The icosahedral viruses' envelope contains glycoprotein _____, which are encoded by the virus.
    spikes
  17. Between the envelope and capsid of icosahedral viruses, ______ proteins may be found, which come from either the host or virus.
    tegument
  18. Name the virus type:
    - the capsid consists of a long tube of protein, with the genome coiled inside
    - vary in length, depending on genome size
    - include bacteriophages as well as animal viruses
    Filamentous viruses
  19. Filamental viruses show ______ symmetry.
    helical

    • The pattern of capsid monomers forms a helical tube around the genome, which usually winds helically within the tube.
    • Image Upload 1
  20. _____ viruses have:
    - have complex multipart structures
    - T4 bacteriophages
    Asymetrical
  21. Pox viruses:
    - their genome is surrounded by _____ layers
    - A core envelope studded with ____ proteins
    - An _____ membrane
    - Also contain a large number of ______ proteins.
    • - spike
    • - outer
    • - accessory
  22. Viral genomes can be:
    - ____ or ____
    - ____ or ______
    - _____ or _____
    • - DNA, RNA
    • - Single-, double-stranded (ss or ds)
    • - Linear, circular (linear is more common)
  23. Name 3 things that the viral genome may code for:
    • 1. Capsid
    • 2. Envelope proteins
    • 3. Any polymerase not found in the host cell
  24. A classification system for viruses created by the ICTV is based on several criteria:
    - _____ composition
    - Capsid _______
    - _____
    - _____ of the virion
    - ______ range
    • - genome
    • - symmetry
    • - envelope
    • - size
    • - host
  25. Name the famous person:
    - In 1971, proposed the primary distinctions among classes of viruses be:
      - genome composition (RNA or DNA)
      - route used to express mRNA
    - shared 1975 Nobel Prize for work in retroviruses
    David Baltimore
  26. Which of the 7 fundamental groups of viral species is this: double-stranded DNA
    - uses its own or host DNA polymerases for replication
    Group I
  27. Which of the 7 fundamental groups of viral species is this: single-stranded DNA
    - Required DNA polymerase to generate a complementary strand
    Group II
  28. Which of the 7 fundamental groups of viral species is this: double-stranded RNA
    - Requires RNA-dpeendent RNA polymerase to make mRNA and genomic RNA
    Group III
  29. Which of the 7 fundamental groups of viral species is this: (+) single-stranded RNA
    - Requires RNA-dependent RNA polymerase to make a template for mRNA and genome replication
    Group IV
  30. Which of the 7 fundamental groups of viral species is this: (-) single-stranded RNA
    - Requires RNA-dependent RNA polymerase to make mRNA and replicate its genome
    Group V
  31. Which of the 7 fundamental groups of viral species is this: RNA retroviruses
    - packages its own reverse transcriptase to make dsDNA
    Group VI
  32. Which of the 7 fundamental groups of viral species is this: DNA pararetroviruses
    Group VII
  33. Definition: Genes of common ancestry in two genomes that share the same function.
    orthologs
  34. A ____ ____ ____ is a DNA sequence that can express a recombinant gene in an animal or plant cell.
    gene transfer vector
  35. The viruses used as gene transfer vectors are those whose replicative cycles establish a viral genome within the _____ _____.
    host nucleus
  36. Some of the first viral vectors were made from double-stranded DNA viruses such as _______.
    adenoviruses
  37. An exciting class of gene transfer vectors are derived from _____, such as the lentivirus HIV
    - Lentiviral vectors or tentivectors
    retroviruses
  38. In general, gene therapy is approved only for conditions that are ___-_____ and for which alternative therapies are ______.
    life-threatening, inadequate
  39. Safety features of viral vectors include:
    - _______ virulence genes
    - avoiding genome ______ next to oncogene
    - altering tissue _____
    - _____ germ-line infection
    • - deleting
    • - insertion
    • - specificity
    • - avoiding
  40. A virus is a noncellular particle that can reproduce only within a ______ ____.
    living cell
  41. A complete viral particle is called a _____, and is composed of a nucleic acid genome, surrounded by a protein _____.
    virion, capsid
  42. Viruses can be divided into two main types:
    symmetrical and asymmetrical
  43. The Baltimore system classifies viruses mainly on their means of:
    mRNA synthesis
  44. Viruses have been used for ___ ____.
    Examples: Lentiviruses and adenoviruses
    gene therapy
  45. Viroids are _____ agents that infect _____.



    C) RNA; plants
  46. What do all viruses contain?



    B) A capsid and a genome
Author
tulipyoursweety
ID
315620
Card Set
Microbiology 351 Exam 1 Flashcards - Set 7
Description
Viruses I
Updated