Poxviridae and Smallpox Quiz
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Questions and Answers

What is the main difference between Chordopoxvirinae and Entomopoxvirinae?

  • Chordopoxvirinae and Entomopoxvirinae both infect vertebrates and humans
  • Chordopoxvirinae and Entomopoxvirinae both infect insects
  • Chordopoxvirinae infects vertebrates and humans, while Entomopoxvirinae infects insects (correct)
  • Chordopoxvirinae infects insects, while Entomopoxvirinae infects vertebrates and humans

    • What evidence suggests the early existence of smallpox?

  • Smallpox scars on Egyptian mummies (correct)
  • Genetic studies on smallpox virus
  • Smallpox vaccination records
  • Written records from the 10th century AD

    • What is the disease progression of smallpox?

  • Asymptomatic phase, respiratory infection, sudden onset fever, rash, blisters covering body and airways, painful rash, fever resumes
  • Respiratory infection, asymptomatic phase, sudden onset fever, rash, painful rash, fever resumes, blisters covering body and airways
  • Respiratory infection, sudden onset fever, asymptomatic phase, rash, painful rash, fever resumes, blisters covering body and airways (correct)
  • Sudden onset fever, respiratory infection, asymptomatic phase, rash, painful rash, blisters covering body and airways

    • What led to the development of the concept of vaccination for smallpox?

    <p>Variolation</p> Signup and view all the answers

    Where do poxviruses replicate?

    <p>In the cytoplasm</p> Signup and view all the answers

    What is the structure that houses the DNA and viral enzymes for mRNA synthesis in poxviruses?

    <p>Tubular structure within the core</p> Signup and view all the answers

    How are poxvirus genes expressed?

    <p>In a regulated transcriptional cascade controlled by viral transcription factors</p> Signup and view all the answers

    What is the function of virus-coded resolvase in poxvirus replication?

    <p>Resolving large DNA concatemers into monomers</p> Signup and view all the answers

    How are intermediate and late genes transcribed in poxviruses?

    <p>Only after DNA replication has started, with distinct promoters and initiation factors</p> Signup and view all the answers

    What is the final shape of mature virions in poxviruses?

    <p>Spheres</p> Signup and view all the answers

    How do vaccinia viruses get transported to the plasma membrane for release as extracellular virus (EV)?

    <p>By actin tails</p> Signup and view all the answers

    What is the composition of lateral bodies in poxviruses?

    <p>Proteins of unknown composition and function</p> Signup and view all the answers

    What is the role of viral proteins in poxvirus replication?

    <p>Promote actin polymerization/depolymerization for budding out of the host cell</p> Signup and view all the answers

    What is the function of viroplasm in poxvirus assembly?

    <p>House DNA and viral enzymes for mRNA synthesis</p> Signup and view all the answers

    What is the primary mode of cell entry for mature virus (MV) and extracellular virus (EV) forms of poxviruses?

    <p>Microvilli projections attachment</p> Signup and view all the answers

    What is the primary mode of transmission for smallpox?

    <p>Respiratory infection</p> Signup and view all the answers

    What was the purpose of variolation in the context of smallpox?

    <p>To induce a less severe form of the disease</p> Signup and view all the answers

    Which organisms are infected by Entomopoxvirinae?

    <p>Insects</p> Signup and view all the answers

    What is the size range of linear double-stranded DNA in poxviruses?

    <p>150-250kb</p> Signup and view all the answers

    What is the primary mode of cell entry for mature virus (MV) and extracellular virus (EV) forms of poxviruses?

    <p>Direct injection of DNA into the cytoplasm</p> Signup and view all the answers

    What is the function of viroplasm in poxvirus assembly?

    <p>Assembly site for viral membrane structures</p> Signup and view all the answers

    What is the composition of lateral bodies in poxviruses?

    <p>Proteins of unknown composition and function</p> Signup and view all the answers

    What is the role of viral proteins in poxvirus replication?

    <p>Promote actin polymerization/depolymerization for budding out of the host cell</p> Signup and view all the answers

    How are poxvirus genes expressed?

    <p>In a regulated transcriptional cascade controlled by viral transcription factors.</p> Signup and view all the answers

    What is the final shape of mature virions in poxviruses?

    <p>Spherical with internal core and lateral bodies</p> Signup and view all the answers

    What is the structure that houses the DNA and viral enzymes for mRNA synthesis in poxviruses?

    <p>Tubular structure within the core</p> Signup and view all the answers

    What is the main difference between Chordopoxvirinae and Entomopoxvirinae?

    <p>Host range, infecting vertebrates vs. insects respectively.</p> Signup and view all the answers

    What is the disease progression of smallpox?

    <p>Prodrome phase followed by rash phase then pustular phase.</p> Signup and view all the answers

    How do vaccinia viruses get transported to the plasma membrane for release as extracellular virus (EV)?

    <p>Golgi-derived cisternae wrapping and transport via microvilli projections.</p> Signup and view all the answers

    Study Notes

    Poxvirus Replication and Assembly Process Overview

    • Poxviruses have covalently closed hairpin ends with no free 3’ and 5’ ends and contain 150-250 genes, each with its own transcriptional promoter and no introns in the genome.
    • Virion sections show a biconcave core flanked by lateral bodies, containing proteins of unknown composition and function, and a tubular structure within the core housing the DNA and viral enzymes for mRNA synthesis.
    • Poxviruses have two infectious forms, Mature Virus (MV) and Extracellular Virus (EV), with distinct membrane compositions and modes of cell entry.
    • Poxviruses replicate in the cytoplasm, with virus-coded enzymes carrying out early RNA synthesis and packaging. The genes are expressed in a regulated transcriptional cascade controlled by viral transcription factors.
    • Sequential gene expression ensures sufficient replicated DNA before structural proteins are synthesized, and DNA replication forms "DNA factories" visible under electron microscopy (EM).
    • Poxviruses produce large DNA concatemers that are later resolved into monomers by a virus-coded resolvase and joined by DNA ligase.
    • Intermediate and late genes are transcribed only after DNA replication has started, with distinct promoters and initiation factors, and postreplicative mRNAs have poly(A) extensions and 3’ end heterogeneity.
    • The assembly of vaccinia virions is a complex process involving de novo synthesis of rigid, crescent-shaped membrane structures that mature into spheres and enclose viroplasm.
    • Immature virions develop internal core and lateral bodies, acquiring their final shape as mature virions, and a small proportion further mature to become extracellular virus (EV).
    • Vaccinia viruses can be wrapped in Golgi-derived cisternae, transported to the plasma membrane by actin tails, and released as extracellular virus (EV) that can remain attached to cell membrane via microvilli projections.
    • Poxviruses produce actin ‘comet’ tails using viral proteins to promote actin polymerization/depolymerization for budding out of the host cell, and make several proteins that target host defenses against invading pathogens.

    Poxvirus Replication and Assembly Process Overview

    • Poxviruses have covalently closed hairpin ends with no free 3’ and 5’ ends and contain 150-250 genes, each with its own transcriptional promoter and no introns in the genome.
    • Virion sections show a biconcave core flanked by lateral bodies, containing proteins of unknown composition and function, and a tubular structure within the core housing the DNA and viral enzymes for mRNA synthesis.
    • Poxviruses have two infectious forms, Mature Virus (MV) and Extracellular Virus (EV), with distinct membrane compositions and modes of cell entry.
    • Poxviruses replicate in the cytoplasm, with virus-coded enzymes carrying out early RNA synthesis and packaging. The genes are expressed in a regulated transcriptional cascade controlled by viral transcription factors.
    • Sequential gene expression ensures sufficient replicated DNA before structural proteins are synthesized, and DNA replication forms "DNA factories" visible under electron microscopy (EM).
    • Poxviruses produce large DNA concatemers that are later resolved into monomers by a virus-coded resolvase and joined by DNA ligase.
    • Intermediate and late genes are transcribed only after DNA replication has started, with distinct promoters and initiation factors, and postreplicative mRNAs have poly(A) extensions and 3’ end heterogeneity.
    • The assembly of vaccinia virions is a complex process involving de novo synthesis of rigid, crescent-shaped membrane structures that mature into spheres and enclose viroplasm.
    • Immature virions develop internal core and lateral bodies, acquiring their final shape as mature virions, and a small proportion further mature to become extracellular virus (EV).
    • Vaccinia viruses can be wrapped in Golgi-derived cisternae, transported to the plasma membrane by actin tails, and released as extracellular virus (EV) that can remain attached to cell membrane via microvilli projections.
    • Poxviruses produce actin ‘comet’ tails using viral proteins to promote actin polymerization/depolymerization for budding out of the host cell, and make several proteins that target host defenses against invading pathogens.

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    Description

    Test your knowledge of Poxviridae and Smallpox with this quiz! Learn about the two subfamilies of Poxviridae, their hosts, and the history of the smallpox disease. Explore the eradication of smallpox through vaccination and its impact on global health.

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