Basic Virology Quiz

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which type of viral genomic material can be both double-stranded and single-stranded?

Neither DNA nor RNA viruses

Only DNA viruses

Both DNA and RNA viruses (correct)

Only RNA viruses

Which symmetry is characterized by capsomers arranged in a hollow coil structure?

Cubic symmetry

Complex symmetry

Helical symmetry (correct)

Icosahedral symmetry

What is the primary function of capsid proteins in viruses?

Assisting in host cell division

Protecting nucleic acids and facilitating attachment (correct)

Synthesizing viral proteins

Producing energy for viral replication

Which type of virus is classified as non-enveloped and contains segmented RNA?

Bunyaviruses Signup and view all the answers

Which of the following viral families includes both negative-sense and positive-sense RNA viruses?

Orthomyxoviruses Signup and view all the answers

Which type of viral genomic material is typically circular and haploid?

Circular ssDNA Signup and view all the answers

What is the main characteristic of viruses with complex symmetry?

They have a protein capsid with a complicated structure. Signup and view all the answers

Which of the following correctly pairs a viral family with its genomic characteristics?

Picornaviruses - +ssRNA, nonsegmented Signup and view all the answers

Which type of viral infection remains dormant and can reactivate later, such as in herpes virus infections?

Latent infection Signup and view all the answers

What is required for the transportation of specimens meant for virus isolation?

Cold chain transport Signup and view all the answers

In terms of diagnostic techniques, which method is rated highest for diagnosing viral infections?

Antigen detection Signup and view all the answers

Which viral infection type refers to diseases with a long incubation period often lasting years?

Slow virus infections Signup and view all the answers

Which structure is typically used for the cultivation of viruses, as they are obligate intracellular parasites?

Tissue and cell cultures Signup and view all the answers

What type of microscopy is essential for determining the size and shape of viruses?

Electron microscopy Signup and view all the answers

What is the definition of a virion?

A complete infectious virus particle Signup and view all the answers

Which of the following correctly describes a prion?

An infectious agent composed only of protein without nucleic acid Signup and view all the answers

Which of the following is a characteristic of chronic viral infections?

They can lead to carrier states. Signup and view all the answers

Which diagnostic method employs the use of fluorescent antibodies to visualize viral infections?

Fluorescent microscopy Signup and view all the answers

What is the primary distinction between viroids and viruses?

Viroids are composed of circular RNA, while viruses have nucleic acids encased in a protein coat Signup and view all the answers

Which of the following modes of transmission is most commonly associated with viruses?

Inhalation of aerosolized particles Signup and view all the answers

In the context of viral structure, what is a capsid?

The protein coat encasing the nucleic acid Signup and view all the answers

Which type of cell culture involves the use of diploid cell lines?

Secondary cultures Signup and view all the answers

What is the primary target of antiviral drugs during viral replication?

Stage of viral replication Signup and view all the answers

Which of the following vaccines is classified as a killed-virus vaccine?

Rabies vaccine Signup and view all the answers

What are Negri bodies associated with in infected cells?

Rabies infection Signup and view all the answers

Which mode of prevention involves sterilization and disinfection?

General prevention Signup and view all the answers

Which type of cell culture is created using trypsin-treated host cells?

Primary cultures Signup and view all the answers

What is the purpose of Post exposure prophylaxis with HBIG?

Prevention of infection after exposure Signup and view all the answers

Which of the following is an example of mRNA vaccine?

Pfizer-BioNTech COVID-19 vaccine Signup and view all the answers

Which of the following viruses are classified as hepatotropic?

Hepatitis A virus Signup and view all the answers

What structure is characteristic of the viral envelope?

A lipoprotein membrane Signup and view all the answers

Which of the following is NOT a mode of transmission for HIV?

Ingestion Signup and view all the answers

Which type of test is used to detect nucleic acid in viral diagnosis?

PCR/RT PCR Signup and view all the answers

What type of viruses are known for their complex structure, resembling bricks?

Complex viruses Signup and view all the answers

What role do surface protein spikes (peplomers) play in viruses?

They are responsible for host cell attachment. Signup and view all the answers

Which virus primarily replicates in the cytoplasm instead of the nucleus?

Poxvirus Signup and view all the answers

What feature makes viruses sensitive to lipid solvents like ether?

The presence of an envelope Signup and view all the answers

Which of the following accurately describes the use of viral proteins in medicine?

They can be used as vaccine antigens. Signup and view all the answers

What is the primary component of the capsid structure in viruses?

Protein subunits Signup and view all the answers

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.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

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.