26 Questions
Which type of immunity is primarily driven by B cells?
Humoral immunity
What is the basis of haemagglutination tests to detect the presence of viral particles?
Clumping of red blood cells by the viral particles
Which type of immunity does not depend on antibodies for its adaptive immune functions?
Cell-mediated immunity
What is the role of the haemagglutinin viral protein in haemagglutination tests?
Binding to receptors on the membrane of red blood cells
What does haemagglutination refer to in the context of haemagglutination tests?
Clumping of red blood cells by the viral particles
What is the primary function of the virus capsid protein?
To interact with the viral nucleic acid for packaging
How is virus structure typically studied?
Transmission electron microscopy and X-Ray diffraction
In which type of virus is the capsid held together by non-covalent, reversible bonds?
Helical naked capsid viruses
What are the properties of enveloped viruses?
Require killing cells for release of mature virus particles
Which type of immunity may be sufficient to neutralize infection from naked capsid viruses?
Humoral immunity
Cell-mediated immunity primarily depends on antibodies for its adaptive immune functions.
False
Haemagglutination test discriminates between infectious viral particles and particles that are degraded and no longer able to infect.
False
The haemagglutinin viral protein binding to receptors on the membrane of red blood cells results in clumping known as agglutination.
True
Humoral immunity is primarily driven by mature T cells, macrophages, and the release of cytokines in response to an antigen.
False
Viruses can carry on independent metabolism.
False
The nucleoprotein of viruses can have either helical or cubic (icosahedral) structure.
True
Capsid proteins are compactly folded proteins that vary in size, generally ranging from 50 to 350 amino acid residues.
True
Enveloped viruses are resistant to drying, heat, detergents, and acids.
False
Naked capsid viruses require both a humoral and a cellular immune response to neutralize infection.
False
The capsid of icosahedral naked capsid viruses is held together by non-covalent, reversible bonds.
True
Envelope is a sensitive component of enveloped viruses, making them vulnerable to various environmental factors like heat and detergents.
True
Naked capsid viruses can survive well on environmental surfaces and spread easily via fomites.
True
Helical enveloped viruses require killing of host cells for the release of mature virus particles.
True
Transmission electron microscopy (EM) is one of the most powerful methods for studying virus structure.
True
The capsid of a virus functions to protect the viral nucleic acid and interact specifically with the viral nucleic acid for packaging.
True
Virus structure can be studied using X-ray diffraction.
True
Study Notes
- Viruses are the smallest infectious agents, intracellular parasites that can only reproduce in host cells and cannot carry on independent metabolism.
- Viruses are not cellular, consisting only of nucleic acid (DNA or RNA) that is surrounded by a protein coat, called the capsid.
- The capsid protein is the basic unit of structure, serving as protection for the viral nucleic acid, interacting specifically with the nucleic acid for packaging, and assisting in processes of viral and/or host gene regulation.
- Nucleoprotein comes in two basic structure types: helical (rod-shaped with varying widths and specific architectures, no limit to the amount of nucleic acid that can be packaged) and cubic (spherical, limited amount of nucleic acid that can be packaged due to particle size).
- Virus structure is studied using methods such as transmission electron microscopy, cryo EM, and X-ray diffraction.
- Viruses can be classified as naked capsid viruses (no lipid membrane) or enveloped viruses (surrounded by a lipid membrane and glycoproteins).
- Enveloped viruses are sensitive to drying, heat, and detergents, requiring transmission in large droplets and secretions, and cannot survive in the gastrointestinal tract. They may require both humoral and cellular immune responses.
- Naked capsid viruses are resistant to drying, heat, detergents, acids, proteases, and can survive in the gastrointestinal tract. They spread easily via fomites and must kill host cells for release of mature virus particles.
- Humoral immunity produces antigen-specific antibodies and is primarily driven by B cells. Cellular immunity, on the other hand, does not depend on antibodies for its adaptive immune functions and is primarily driven by mature T cells, macrophages, and the release of cytokines in response to an antigen.
- Haemagglutination is a property of some viruses, where viral particles bind to red blood cell membrane receptors, resulting in clumping. This test is used to detect the presence of viral particles but does not discriminate between infectious and degraded particles.
Test your knowledge of viruses and their structure in Microbiology Bt Bio 311 Lecture 6 (Virology) with Dr. Sayed Abo El-Souad. Learn about the smallest infectious agents and their intracellular parasitic nature. Understand the composition of viruses and their inability to carry out independent metabolism.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
