Virology Basics Quiz
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Questions and Answers

What is the primary function of viral glycoproteins during influenza virus infection?

  • They assemble into new virions.
  • They replicate viral RNA.
  • They release viral proteins.
  • They attach the virus to host epithelial cells. (correct)

    • Which process allows some enveloped viruses to deliver their internal components directly to the cytoplasm of a host cell?

  • Fusion (correct)
  • Endocytosis
  • Lysis
  • Budding

    • What mechanism do non-enveloped viruses commonly use to exit the host cell after replication?

  • Cell lysis (correct)
  • Endocytosis
  • Budding
  • Exocytosis

    • During the replication cycle of a virus, which step immediately follows penetration?

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

    What type of viruses utilize host cell membranes to form an envelope during their release phase?

    <p>Enveloped viruses</p> Signup and view all the answers

    What is the first step in the viral life cycle?

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

    What type of nucleic acid is generated during the synthesis of viral components?

    <p>mRNA and viral proteins</p> Signup and view all the answers

    Which of the following best describes the replication cycle of the HIV virus?

    <p>It undergoes cell fusion to enter the host.</p> Signup and view all the answers

    What are viroids primarily composed of?

    <p>Naked single-stranded RNA without protein coat</p> Signup and view all the answers

    What is the primary function of the outer viral proteins?

    <p>Mediate attachment to specific receptors</p> Signup and view all the answers

    Which of the following correctly describes prions?

    <p>Entirely made of protein without nucleic acids</p> Signup and view all the answers

    Which statement about the replication of viruses is true?

    <p>The entire virus enters the cells during the penetration phase.</p> Signup and view all the answers

    What type of genetic material does a retrovirus contain?

    <p>Single-stranded RNA with reverse transcriptase</p> Signup and view all the answers

    What occurs during the biosynthesis phase of virus replication?

    <p>Viral proteins and nucleic acids are synthesized.</p> Signup and view all the answers

    How do naked viruses typically release their components from host cells?

    <p>By cell lysis</p> Signup and view all the answers

    Which characteristic is NOT used in virus classification?

    <p>Presence of metabolic enzymes</p> Signup and view all the answers

    What type of nucleic acid do viruses possess?

    <p>Either DNA or RNA</p> Signup and view all the answers

    What is the primary function of the virus capsid?

    <p>To protect the viral genome and help entry into host cells</p> Signup and view all the answers

    Which of the following is a characteristic of a ds RNA virus?

    <p>Contains double-stranded RNA</p> Signup and view all the answers

    What structural component distinguishes an enveloped virus from a naked virus?

    <p>Presence of a lipid bilayer membrane</p> Signup and view all the answers

    How are viral genomes generally categorized?

    <p>By nucleic acid type and structure</p> Signup and view all the answers

    What are capsomeres?

    <p>The structural components of the virus capsid</p> Signup and view all the answers

    Which shape is NOT one of the common capsid structures of viruses?

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

    What role do glycoprotein spikes on a virus serve?

    <p>Host cell attachment</p> Signup and view all the answers

    What are the main components of a virus particle?

    <p>Internal core and protein coat</p> Signup and view all the answers

    Why are viruses classified as obligate intracellular parasites?

    <p>They require a host cell to replicate.</p> Signup and view all the answers

    Which statement correctly describes the size of viruses?

    <p>They range from about 10 to 300 nanometers.</p> Signup and view all the answers

    What type of nucleic acid can viruses contain?

    <p>Both DNA and RNA</p> Signup and view all the answers

    What is the purpose of the capsid in a virus?

    <p>To provide protection to the genome</p> Signup and view all the answers

    Which of the following statements is true regarding viruses?

    <p>They lack ribosomes and cannot synthesize proteins.</p> Signup and view all the answers

    In which decade were the first photographs of viruses obtained?

    <p>1940s</p> Signup and view all the answers

    What defines a virus as acellular?

    <p>It does not have a cellular structure.</p> Signup and view all the answers

    What is a common symptom of infectious mononucleosis caused by Epstein-Barr Virus?

    <p>Swollen lymph glands</p> Signup and view all the answers

    What is the primary mode of transmission for the Epstein-Barr Virus?

    <p>Intimate contact with saliva</p> Signup and view all the answers

    Which influenza virus type is known for causing pandemics?

    <p>Influenzavirus A</p> Signup and view all the answers

    What characterizes the structure of coronaviruses?

    <p>Crown-like spikes</p> Signup and view all the answers

    Which of the following outcomes is commonly associated with a reactivation of Epstein-Barr Virus?

    <p>Asymptomatic presence</p> Signup and view all the answers

    Which strain of coronavirus was first identified in Saudi Arabia in September 2012?

    <p>MERS-CoV</p> Signup and view all the answers

    What percentage of all colds are estimated to be caused by coronaviruses?

    <p>15-30%</p> Signup and view all the answers

    How does the Middle East Respiratory Syndrome (MERS) primarily spread from one person to another?

    <p>Through the air by coughing and sneezing</p> Signup and view all the answers

    What is the incubation period for MERS-CoV infection?

    <p>2-14 days</p> Signup and view all the answers

    Which of the following is NOT a symptom of MERS-CoV infection?

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

    Which type of vaccine contains weakened forms of the virus?

    <p>Live vaccine</p> Signup and view all the answers

    What complications can arise from a MERS-CoV infection?

    <p>Pneumonia and kidney failure</p> Signup and view all the answers

    Which type of vaccine is produced using biotechnology and genetic engineering techniques?

    <p>Subunit vaccine</p> Signup and view all the answers

    What is the primary treatment approach for patients with MERS?

    <p>Supportive care</p> Signup and view all the answers

    Why are antiviral drugs difficult to develop?

    <p>Viruses replicate within host cells.</p> Signup and view all the answers

    Which of the following pre-existing conditions is NOT associated with increased risk for severe MERS?

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

    Study Notes

    Virology Lecture Notes

    • Virology is the study of viruses
    • Viruses were discovered in the 1800s, recognized as something smaller than bacteria that could cause disease
    • Electron microscopes and x-ray crystallography made it possible to see viruses in the 1930s, and the first photographs were taken in 1940
    • Objectives of the lecture include general characteristics, structure and symmetry, classification, and replication steps of viruses

    Viral Characteristics

    • Acellular particles
    • Composed of an internal core, protein coat, and in some cases, a lipoprotein membrane (envelope)
    • Obligate intracellular parasites (need a host cell to reproduce)
    • Lack an ATP generating system
    • Lack ribosomes or protein synthesis mechanisms

    Viral Structure

    • Viruses contain genetic material (DNA or RNA) enclosed in a protein coat called a capsid
    • The capsid is made up of subunits called capsomeres and provides the virus its shape and size. It protects the viral nucleic acid and aids in cell entry
    • Some viruses have a lipid bilayer membrane called an envelope, derived from the host cell membrane

    Viral Genome

    • Viruses have either DNA or RNA genomes
    • Viral nucleic acid can be linear or circular
    • Some can be single-stranded or double-stranded

    Viral Classification

    • Viruses are characterized by their genetic material (DNA or RNA), shape of the capsid, number of capsomeres, size of the capsid, presence or absence of an envelope, type of host, type of disease, target cells and immunological properties

    Viral Replication

    • Attachment - Virus binds to a host cell receptor
    • Penetration - Virus enters the host cell
    • Uncoating - Release of viral genome from its protective capsid
    • Synthesis of viral components - Virus uses the host cell to synthesize mRNA, viral proteins and nucleic acids
    • Assembly - Nucleic acid and viral proteins assemble to form new viruses
    • Release - New viruses are released from the host cell (budding for enveloped viruses, cell lysis for non-enveloped viruses)

    Atypical Virus-like Agents

    • Viroids: Naked ssRNA, requiring host cell DNA-dependent RNA polymerase to replicate; plant pathogens
    • Prions: Entirely composed of proteins, causing fatal neurological diseases in animals (e.g., Mad cow disease)

    Viral Proteins

    • Outer viral proteins mediate attachment to host receptors, induce neutralizing antibodies, and are targets of antibodies
    • Internal viral proteins include structural proteins (capsid proteins in enveloped viruses), non-structural proteins (enzymes), certain ssRNA viruses with transcriptase (RNA dependent RNA polymerase) inside the virions, and retroviruses and HBV with reverse transcriptase

    Viral Infections

    • Include various types: encephalitis, meningitis, common cold, gingivostomatitis, cardiovascular, hepatitis, skin, sexually transmitted diseases, etc.
    • The outcome of viral infection can be cytopathic, latent, or transformational

    Outcomes of Viral Infections

    • Lytic infection: Host cell dies at the end of the virus replication cycle (e.g., influenza and polio)
    • Persistent infection: Host cell remains alive and continues to produce progeny virions (e.g., hepatitis B)
    • Latent infection: The virus enters a latent state, and the host cell remains alive, virus activity becoming dormant until triggered and the virus replicates (e.g., HIV and herpes infections)
    • Transformation Infection: Infected host cells are transformed by the virus (carrying oncogenes), potentially leading to cancer (e.g., some herpesviruses.)

    Specific Viruses

    • Herpesviruses: Can cause fever blisters, genital herpes, latent infections (a-herpes, b-herpes, Y-herpes)
    • Influenza: A common viral respiratory infection, varied strains lead to different pandemics and range of infections.
    • Coronavirus (MERS-CoV): Identified in Saudi Arabia in 2012; transmitted via air and close contact, causing severe acute respiratory illness; no vaccine.
    • HIV: An enveloped virus causing AIDS.
    • CMV (cytomegalovirus): A common infection that can be asymptomatic or cause mononucleosis-like symptoms.

    Prevention and Treatment for Viral Infection

    • Vaccines: Used to prevent viral infections (live/attenuated, inactivated/killed, subunit)
    • Antiviral drugs: Inhibit viral replication or proteins involved in replication in the host cell (they work by inhibiting viral replication inside cells, attachment, uncoating, and Inhibit DNA/RNA synthesis)

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    Virology Lecture Notes (CLS212) PDF

    Description

    Test your knowledge on the fundamental concepts of virology with this quiz. Topics include viral structures, replication cycles, and distinct virus classifications. Perfect for students studying virology or biology.

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