Oncoviruses, Viroids, and Prions Quiz

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Questions and Answers

What is a characteristic effect of oncoviruses on host cells?

They permanently alter the host cell genetic material, potentially causing cancer. (correct)

They cause temporary changes to genetic material.

They exclusively infect bacterial cells.

They primarily affect the nervous system of animals.

What type of pathogen is a viroid?

A virus that primarily infects human cells.

A type of bacteria with nucleic acid.

A single-stranded RNA genome, known as the smallest pathogen. (correct)

An infectious protein particle.

Which statement accurately describes prions?

They are infectious particles composed solely of protein. (correct)

They primarily cause respiratory illnesses in humans.

They have a DNA genome and contain nucleic acids.

They are primarily responsible for lysis of bacterial cells.

Which of the following best describes bacteriophage?

They infect bacterial cells. Signup and view all the answers

What forms can the nucleic acid of viruses take?

Either single-stranded or double-stranded, DNA or RNA. Signup and view all the answers

What is a common characteristic of double-stranded RNA viruses?

They consist of fragmented genomes, with each segment representing a single protein gene. Signup and view all the answers

What is one of the ways microorganisms like oncoviruses can cause damage to host cells?

By leading to the formation of multinucleated cells. Signup and view all the answers

Which virus is known to cause the disease known as Crohn's disease in sheep?

Prion. Signup and view all the answers

Which viruses are known to be transmitted from mother to child?

HIV, HBV, Rubella Signup and view all the answers

What types of transmission are involved in mother to child transmission of viruses?

Transplacental spread and via breast milk Signup and view all the answers

Which of the following is not a method of transmission for blood-borne viruses?

Skin contact with unbroken skin Signup and view all the answers

How are highly sensitive tests like PCR relevant to blood-borne pathogens?

They can detect viruses due to the large volume of blood transfused. Signup and view all the answers

Which viruses are primarily associated with the blood-borne infection category?

HIV, HBV, HCV, Hepatitis B, C, D Signup and view all the answers

What is the primary source of blood for blood-borne viruses as mentioned in the content?

Blood transfusions Signup and view all the answers

Which of the following is a common misconception about blood-borne viruses?

They are often transmitted through skin contact. Signup and view all the answers

What type of arthropods are primarily responsible for acquiring viruses through blood meals?

Mosquitoes, ticks, and sandflies Signup and view all the answers

What does the persistent nucleolus do during cell division?

Leads to separation difficulties during anaphase. Signup and view all the answers

What is a consequence of viral infection in human cells regarding cell membranes?

Incorporation of viral proteins into the membrane. Signup and view all the answers

What is indicated by mitotic delay in relation to viral infections?

It is frequently observed in cell cultures during acute virus infections. Signup and view all the answers

How can viral infections affect the antibody production against human cells?

They can lead to the production of antibodies against altered cell membranes. Signup and view all the answers

What structural change occurs in the human cell membrane during infections?

Dynamic changes in lipid and protein composition. Signup and view all the answers

What directly causes the lysis of the infected cell during T-lymphocyte response to viral antigens?

Action of lymphokines Signup and view all the answers

Which viral effect is specifically associated with the accumulation of cytotoxic substances during viral replication?

Formation of polykaryocytes Signup and view all the answers

Which of the following viruses is known to create rapid polykaryocytosis as a cytotoxic effect?

Measles virus Signup and view all the answers

What phenomenon results from the delayed-type hypersensitivity to viral infection?

Zinkernagel-Dougherty phenomenon Signup and view all the answers

Which component of adenovirus is known to inhibit essential cellular processes such as RNA, DNA, and protein synthesis?

Penton Signup and view all the answers

What is the likely outcome of enterovirus infection in susceptible and unsusceptible cells?

Rapid death without infectious virus production Signup and view all the answers

What type of viral component is associated with the formation of syncytia?

Herpes virus components Signup and view all the answers

What cellular effect is most commonly reported in HeLa cells infected with Vaccinia virus?

Morphological defects due to cytotoxicity Signup and view all the answers

What factor primarily affects horizontal virus transmission among individuals?

Concentration of virus in secretions Signup and view all the answers

Which mechanism is NOT associated with respiratory transmission of viruses?

Direct contact with bodily fluids Signup and view all the answers

Which of the following viruses is primarily transmitted through respiratory means?

Influenza Signup and view all the answers

How does environmental temperature impact respiratory virus survival?

Cooler temperatures increase virus survival Signup and view all the answers

Which type of viruses are shed in feces and vomit and tend to survive longer outside the body?

Enteroviruses Signup and view all the answers

What is a significant factor for the transmission of enteric viruses like rotaviruses?

Large volumes of fluid output Signup and view all the answers

Which transmission pattern is most commonly observed in viral spread?

Horizontal transmission predominantly Signup and view all the answers

What role do aerosols play in respiratory virus transmission?

They can carry viruses over short distances Signup and view all the answers

Study Notes

Oncoviruses and Their Impact

Oncoviruses, such as papillomaviruses and Epstein-Barr virus, cause tumors by permanently altering host cell genetic material, leading to cancer.
They induce cytopathic changes, including cell lysis, DNA alteration, and the formation of multinucleated cells.

Viroids and Prions

Viroids are the smallest known pathogens with a single-stranded RNA genome.
Prions are infectious particles composed solely of protein, lacking nucleic acids, and are highly heat-resistant, affecting the nervous systems of animals (e.g., mad cow disease, scrapie, and Creutzfeldt-Jakob disease).

Bacteriophages

Bacteriophages are viruses that specifically infect bacteria, playing a crucial role in bacterial population control.

Virus Structure and Function

Viral nucleic acids encode genetic information for protein synthesis and can be single or double-stranded DNA or RNA.
Double-stranded DNA viruses consist of a single large molecule, while most double-stranded RNA viruses have segmented genomes, each segment coding for specific proteins.

Transmission of Viruses

Horizontal transmission, primarily between individuals, occurs through various routes including:
- Respiratory or Salivary: E.g., influenza, rhinoviruses, spread via aerosol inhalation or contaminated surfaces.
- Fecal-Oral: E.g., enteroviruses, rotaviruses, shed in feces and vomit, emphasizing environmental persistence.
- Blood-Borne: E.g., HIV, HBV, transmitted through contaminated blood, posing risks during transfusions.
- Mother to Child: E.g., HBV, HIV, transmitted during pregnancy, birth, or through breastfeeding, with three main pathways: proviral DNA integration, transplacental spread, perinatal contact.

Cytopathic Effects of Viral Infections

Viral infection can induce cytotoxicity, causing cell damage through:
- Production of Toxic Substances: Accumulation of viral components can be cytotoxic and induce morphological defects in cells.
- Induction of Mitotic Delay or Inhibition: Altered cell division dynamics may occur during viral infections.
- Membrane Changes: Viral proteins may incorporate into host membranes, potentially leading to immune responses and cell lysis.

Important Viral Pathogenicity Mechanisms

The presence of viral components affects cellular processes, leading to severe pathological outcomes and facilitating disease progression.

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Description

Test your knowledge on oncoviruses, viroids, and prions, including their structures, functions, and impacts on host organisms. Explore how these pathogens affect health and contribute to diseases like cancer and prion disorders.