Viral Protein Nanomachines and Genetic Material Delivery Quiz

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What is the primary function of the capsid in a virus?

To protect the genetic material

What does the term 'nucleocapsid' refer to?

The combination of the protein coat and viral nucleic acid

What is the function of the viral envelope?

To play a crucial role in host recognition and cell entry

What is the size range of virions?

50 to 250 nanometers Signup and view all the answers

What is the fatality rate for the mentioned pandemic?

0.13% Signup and view all the answers

What is the impact of the Asian Flu on public health?

Significant impact despite a lower mortality rate Signup and view all the answers

What process exposes viral genetic material for replication inside the host cell?

Uncoating Signup and view all the answers

What is responsible for constructing new virions during viral replication?

Late viral gene expression Signup and view all the answers

What is a direct consequence of rapid mutations in influenza viruses?

The need for frequent updates to influenza vaccines Signup and view all the answers

What allows the virus to escape the immune system's memory and cause recurrent infections?

Antigenic drift Signup and view all the answers

What contributes to the seasonal variability of the flu?

Rapid mutation rate Signup and view all the answers

What makes it challenging to predict vaccine efficacy?

Constantly changing nature of the virus Signup and view all the answers

What poses a significant challenge for individuals with compromised immune systems?

Rapid mutations in influenza viruses Signup and view all the answers

What does antigenic drift and mutation in Influenza A lead to?

Emergence of entirely new strains with pandemic potential Signup and view all the answers

What primarily infects humans and causes seasonal epidemics due to its slower mutation rate?

Influenza B Signup and view all the answers

What can infect a wide variety of animals, including humans, has rapid mutation, and the potential to cause pandemics?

Influenza A Signup and view all the answers

What is the structure of Tobacco Mosaic Virus (TMV)?

Helical structure with a protein coat enclosing RNA Signup and view all the answers

What are the effects of TMV on tobacco plants?

Mosaic-like spots, stunted growth, and reduced crop yield Signup and view all the answers

Which virus causes Ebola Virus Disease (EVD) in humans and primates?

Ebola virus Signup and view all the answers

How is Rabies primarily transmitted?

Through saliva Signup and view all the answers

What is the primary classification basis for viruses by the International Committee on Taxonomy of Viruses (ICTV)?

Genetic and biological properties Signup and view all the answers

How many classes categorize viruses in the Baltimore classification system?

Seven Signup and view all the answers

What does a virion lack, making it acellular?

Cellular machinery for metabolism, ATP synthesis, and ribosomes Signup and view all the answers

Which cellular structure can viruses potentially utilize for membranes?

Host cell's endoplasmic reticulum Signup and view all the answers

What is the genetic material enclosed within a virion primarily consisting of?

Both RNA and DNA Signup and view all the answers

What is the core of a virus filled with in its intracellular form?

Tightly packed double-stranded DNA Signup and view all the answers

What are the structures like lateral bodies with unknown functions found in some viruses?

Unknown Signup and view all the answers

Which classification system uses ranks like order, family, subfamily, genus, and species for viruses?

International Committee on Taxonomy of Viruses (ICTV) Signup and view all the answers

What do viruses use to deliver their genetic material into host cells?

Capsids and viral envelopes Signup and view all the answers

Why are viruses considered 'pirates' of the cell?

They reprogram host cells to produce more virions Signup and view all the answers

What characteristic do viruses lack, leading to ongoing discussions about their classification as living or non-living entities?

Metabolic processes Signup and view all the answers

What characteristic do animal viruses exploit to adhere to specific receptors on the surface of host cells?

Viral glycoproteins Signup and view all the answers

Which virus adheres to sialic acid on the surface of host cells, particularly in the respiratory tract, using the HA glycoprotein for binding?

Influenza virus Signup and view all the answers

What is a characteristic of viruses that indicates their dependence on host cells for replication?

Inert outside of a host cell Signup and view all the answers

What is a common impact of influenza pandemics caused by different strains of the influenza A virus?

Significant impacts on global public health Signup and view all the answers

What was the estimated death toll worldwide due to the 1918 'Spanish Flu' pandemic caused by an H1N1 strain?

20 to 100 million deaths Signup and view all the answers

What do viruses tend to have in terms of their genomes?

Compact genomes Signup and view all the answers

What do viruses lack, leading to ongoing discussions about their classification as living or non-living entities?

Metabolic processes Signup and view all the answers

What is the role of viral glycoproteins in animal viruses?

Mediate adherence to specific receptors on host cells Signup and view all the answers

What is the primary characteristic of viruses that leads to ongoing debates about their classification as living or non-living entities?

Lack of metabolic processes Signup and view all the answers

What is the primary consequence of antigenic drift in influenza A viruses?

Creation of new viral strains Signup and view all the answers

Which protein is critical in clathrin-mediated endocytosis, a mechanism for cells to engulf molecules?

Clathrin Signup and view all the answers

What mechanism involves the creation of pores in the host cell membrane for viral genome injection?

Pore-mediated penetration Signup and view all the answers

Which virus enters host cells through endocytosis, triggered by the low pH environment of the endosome?

Influenza viruses Signup and view all the answers

What impact did the emergence of the new H1 subtype have on the 1918 Spanish Flu?

Increased virulence Signup and view all the answers

What is the primary consequence of changes in the hemagglutinin glycoprotein near the receptor-binding site due to antigenic drift?

Making the virus less recognizable to the immune system Signup and view all the answers

What is the primary target of antigenic drift in influenza A viruses?

HA and NA genes Signup and view all the answers

What is the primary function of the hemagglutinin glycoprotein in influenza viruses?

Binding to host cell receptors Signup and view all the answers

Which virus utilizes envelope fusion with the plasma membrane to enter the host cell?

Rubulaviruses Signup and view all the answers

What is the primary outcome of the lack of preexisting immunity to a new H1 subtype in a pandemic virus?

Rapid spread of the virus Signup and view all the answers

What is the primary characteristic of clathrin-mediated endocytosis?

Mechanism for cells to engulf molecules Signup and view all the answers

What is the primary characteristic of endocytosis with fusion with the endosomal membrane?

Triggered by low pH environment Signup and view all the answers

Study Notes

Viral Protein Nanomachines: Delivery Systems for Genetic Material

Viruses have evolved specialized protein structures, such as capsids and viral envelopes, to deliver their genetic material into host cells.
Viruses are considered "pirates" of the cell, as they reprogram host cells to produce more virions, utilizing the cell’s energy and resources.
Highly evolved parasites, viruses have evolved sophisticated mechanisms to exploit host cells for their reproduction.
Viruses tend to have compact genomes, using their genetic material efficiently for replication and infection processes.
Viruses exhibit some characteristics of living organisms but lack others, leading to ongoing discussions about their classification as living or non-living entities.
Viruses lack metabolic processes, cellular structure, and an independent life cycle, which are characteristics of living organisms.
Inert outside of a host cell, viruses are completely dependent on host cells for replication, indicating characteristics of non-living entities.
The classification of viruses as living or non-living varies depending on the criteria used for defining life.
Animal viruses have evolved mechanisms to adhere to specific receptors on the surface of host cells, often mediated by viral glycoproteins.
The influenza virus adheres to sialic acid on the surface of host cells, particularly in the respiratory tract, using the HA glycoprotein for binding.
Influenza pandemics caused by different strains of the influenza A virus, such as the 1918 'Spanish Flu' and the 1950s 'Asian Flu,' had significant impacts on global public health.
The 1918 'Spanish Flu' pandemic, caused by an H1N1 strain, resulted in an estimated 20 to 100 million deaths worldwide, with an exceptionally high fatality rate.

Influenza A Virus Antigenic Drift and Entry Mechanisms

Influenza A viruses can infect a wide range of host species and have caused most influenza pandemics in history.
Antigenic drift in influenza A viruses, particularly in the HA and NA genes, leads to the creation of new viral strains, necessitating updates to seasonal flu vaccines.
Antigenic drift can result in changes in the hemagglutinin glycoprotein, particularly near the receptor-binding site, making the virus less recognizable to the immune system.
The emergence of a new mutant form of hemagglutinin (HA), specifically the H1 subtype, in the 1918 Spanish Flu had a significant impact on the virulence of the virus.
The lack of preexisting immunity to the new H1 subtype contributed to the rapid spread of the virus and increased severity of disease.
The new H1 subtype may have undergone further mutations over time (antigenic drift), potentially altering the virus’s antigenic properties.
Various mechanisms by which viruses can gain entry into host cells include pore-mediated penetration, endocytosis with dissolution of endosomal membrane, envelope fusion with plasma membrane, and endocytosis with fusion with endosomal membrane.
Clathrin is a critical protein involved in clathrin-mediated endocytosis, a mechanism by which cells engulf molecules or particles from their external environment.
Pore-mediated penetration involves the creation of pores in the host cell membrane through which the viral genome is injected, used by some human rhinoviruses and bacteriophages.
Endocytosis involves the virus being engulfed by the host cell and forming an endosome, followed by dissolution of the endosomal membrane, used by adenoviruses.
Envelope fusion with the plasma membrane allows certain viruses to enter the cell without being taken up into an endosome, employed by Morbilliviruses and Rubulaviruses.
Endocytosis with fusion with the endosomal membrane allows some enveloped viruses to enter host cells through endocytosis, triggered by the low pH environment of the endosome, used by Herpes Simplex Virus and influenza viruses.

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