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Questions and Answers
Which type of viral genomic material can be both double-stranded and single-stranded?
Which symmetry is characterized by capsomers arranged in a hollow coil structure?
What is the primary function of capsid proteins in viruses?
Which type of virus is classified as non-enveloped and contains segmented RNA?
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Which of the following viral families includes both negative-sense and positive-sense RNA viruses?
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Which type of viral genomic material is typically circular and haploid?
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What is the main characteristic of viruses with complex symmetry?
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Which of the following correctly pairs a viral family with its genomic characteristics?
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Which type of viral infection remains dormant and can reactivate later, such as in herpes virus infections?
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What is required for the transportation of specimens meant for virus isolation?
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In terms of diagnostic techniques, which method is rated highest for diagnosing viral infections?
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Which viral infection type refers to diseases with a long incubation period often lasting years?
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Which structure is typically used for the cultivation of viruses, as they are obligate intracellular parasites?
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What type of microscopy is essential for determining the size and shape of viruses?
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What is the definition of a virion?
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Which of the following correctly describes a prion?
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Which of the following is a characteristic of chronic viral infections?
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Which diagnostic method employs the use of fluorescent antibodies to visualize viral infections?
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What is the primary distinction between viroids and viruses?
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Which of the following modes of transmission is most commonly associated with viruses?
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In the context of viral structure, what is a capsid?
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Which type of cell culture involves the use of diploid cell lines?
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What is the primary target of antiviral drugs during viral replication?
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Which of the following vaccines is classified as a killed-virus vaccine?
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What are Negri bodies associated with in infected cells?
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Which mode of prevention involves sterilization and disinfection?
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Which type of cell culture is created using trypsin-treated host cells?
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What is the purpose of Post exposure prophylaxis with HBIG?
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Which of the following is an example of mRNA vaccine?
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Which of the following viruses are classified as hepatotropic?
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What structure is characteristic of the viral envelope?
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Which of the following is NOT a mode of transmission for HIV?
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Which type of test is used to detect nucleic acid in viral diagnosis?
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What type of viruses are known for their complex structure, resembling bricks?
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What role do surface protein spikes (peplomers) play in viruses?
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Which virus primarily replicates in the cytoplasm instead of the nucleus?
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What feature makes viruses sensitive to lipid solvents like ether?
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Which of the following accurately describes the use of viral proteins in medicine?
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What is the primary component of the capsid structure in viruses?
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Study Notes
General Properties of Viruses
- Viruses are the smallest infectious agents, measuring 20-300 nm in diameter.
- They are obligate intracellular parasites, requiring a host cell for replication.
- A virus consists of nucleic acid (RNA or DNA) encased in a protein coat (capsid).
- Some viruses are surrounded by a lipid-containing envelope, forming a complete infectious unit known as a virion.
Types of Viruses
- Defective viruses need assistance from another virus to replicate (e.g., HBV and HDV).
- Viroids are small RNA molecules without proteins that cause plant diseases.
- Prions are protein-only infectious agents that cause neurodegenerative diseases in animals and humans.
Viral Genomic Materials
- Viral nucleic acids can be DNA (dsDNA, ssDNA) or RNA (dsRNA, ssRNA) and can vary in structure (circular, linear, segmented).
- Viruses exhibit diverse characteristics based on their genetic material and structure.
Classification of Viruses
- Appearances based on nucleic acid composition, protein capsid morphology, and transmission modes inform virus classification.
- Viruses can be categorized by their tissue targeting, symptomatology, and mechanisms of transmission.
Modes of Transmission
- Viruses can be transmitted through different routes including:
- Ingestion: e.g., Hepatitis A (HAV), Poliovirus.
- Transfusion: e.g., HIV, Hepatitis B (HBV), Cytomegalovirus (CMV).
- Sexual contact: e.g., HIV, HSV-2, Human papillomavirus (HPV).
- Vertical transmission (mother to child): e.g., HIV, HBV.
- Vector-borne: e.g., Dengue and Yellow fever.
- Zoonotic infections: e.g., Rabies, MERS.
Viral Pathogenesis
- Pathogenicity involves a sequence of events: entry, replication, spread, cell injury, recovery, and virus shedding.
- Different viruses have specific tropisms (targeting of certain body tissues).
Laboratory Diagnosis of Viral Infections
- Laboratory techniques include:
- Electron Microscopy for size and shape.
- Viral Culture using cell lines or living organisms.
- Antigen Detection to identify viral proteins.
- Nucleic Acid Detection through PCR or NA probes.
- Antibody Detection to reveal immune response to viral antigens.
Specimen Collection
- Specimens for viral isolation must be transported on ice in viral transport medium (VTM).
Treatment and Prevention of Viral Infections
- Antiviral therapies target specific stages of viral replication to inhibit function without damaging host cells.
- Prevention strategies encompass both general practices (hand washing, sterilization) and specific methods (vaccination).
- Immunization includes various vaccine types such as killed (rabies), attenuated (MMR), recombinant (Hepatitis B), and mRNA (COVID-19).
Key Applications of Viral Structure
- Classification of viruses and identification of specific proteins for tissue and host cell attachment.
- Diagnosis through nucleic acid detection and serological tests.
- Viral proteins can serve as vaccine antigens.
Clinical Examples of Viral Persistence
- Chronic infections: e.g., Hepatitis C can lead to long-term virus production.
- Latent infections: e.g., Herpes Simplex Virus can reactivate after a dormant period.
- Slow virus infections: e.g., Subacute sclerosing panencephalitis (SSPE) with lengthy incubation periods.
Important Considerations in Viral Research
- Understanding specific viral structures aids in the development of targeted therapies and vaccines.
- Recognizing modes of transmission and replication steps are crucial for control and prevention strategies against viral diseases.
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Description
Test your understanding of basic virology concepts, including virus structures, classification, and transmission methods. This quiz also covers the replication cycle of viruses, diagnostic tests, and prevention strategies. Ideal for students studying general virology.
