Virus Naming and Classification

Questions and Answers

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

To recognize and respond to immune cells

To protect the viral nucleic acid (correct)

To facilitate genome replication

To provide attachment to host cells

What is a characteristic of viral genomes compared to cellular genomes?

They can be only DNA

They are larger in size

They are always double-stranded

They are much smaller (correct)

What determines the specificity of a virus for a particular host cell?

The type of nucleic acid in the viral genome

The shape of the viral genome

The affinity of viral surface proteins for complementary proteins on the host cell surface (correct)

The size of the viral genome

What is the basis for viral classification?

The size and shape of the virus Signup and view all the answers

What do capsomeres refer to in a virus?

Protein subunits of the capsid Signup and view all the answers

What is a common characteristic of viral shapes?

They can be classified into three basic types Signup and view all the answers

What is a characteristic of generalist viruses?

They infect many kinds of cells or many different hosts Signup and view all the answers

What is the term for the combination of the capsid and genomic nucleic acids?

Nucleocapsid Signup and view all the answers

Which of the following is a criterion for virus naming and classification?

All of the above Signup and view all the answers

What is true about the type of nucleic acid in viral genomes?

They can be either DNA or RNA but not both Signup and view all the answers

What is the term for a complete virus particle that includes a nucleic acid, a capsid, and in some cases an envelope?

Virion Signup and view all the answers

What is a common feature of viral hosts?

All types of organisms are susceptible to some virus Signup and view all the answers

What is the primary function of a virus?

To deliver genetic information into a host cell Signup and view all the answers

What is a characteristic of viruses?

They are minuscule, acellular, and infectious agents Signup and view all the answers

What is the result of a virus recruiting a cell's metabolic pathways?

The cell's metabolic pathways are increased Signup and view all the answers

What is a consequence of viral infections?

Most diseases in the industrialized world are caused Signup and view all the answers

What is a characteristic of viruses in relation to their host cells?

They require the host cell's metabolic pathways Signup and view all the answers

What is the meaning of the Greek word 'virus'?

Poison Signup and view all the answers

What is a characteristic of viruses in relation to their structure?

They have no cytoplasmic membrane, cytosol, or organelles Signup and view all the answers

What is the primary component of a virus?

Genetic information Signup and view all the answers

Study Notes

Virus Naming and Classification

Virus names are usually based on the disease they are associated with, cyto-pathology they cause, site of isolation, places or people that discovered them, and biochemical features.
Examples of virus names include HIV, Measles, Cytomegalovirus, Adenovirus, Enterovirus, Rhinovirus, RSV, Epstein-Barr virus, West Nile Fever, and Ebola.

Viral Taxonomy

Viral classification is based on size and shape, whether they are enveloped or naked, nucleic acid composition, genome organization, and antigenic differences.
Examples of classified viruses include Rotavirus and H1N1.

Virus Structure

Capsomere is a protein subunit of the capsid.
Capsid provides protection for viral nucleic acid and means of attachment to host cells.
Capsid is composed of proteinaceous subunits called capsomeres.
Capsomeres may be made of single or multiple types of proteins.
Nucleocapsid is the capsid plus genomic nucleic acids (DNA or RNA).

Characteristics of Viruses

Viruses show more variety in the nature of their genomes than cells.
The primary way scientists categorize and classify viruses is based on their genetic material.
Viral genomes can be DNA or RNA but never both.
Viral genomes can be dsDNA, ssDNA, dsRNA, or ssRNA.
Viral genomes can be linear and segmented or single and circular.
Viral genomes are much smaller than genomes of cells.

Hosts of Viruses

Most viruses infect only particular host cells due to the affinity of viral surface proteins for complementary proteins on host cell surface.
Viruses can be specific to particular kinds of cells or hosts.
Generalists infect many kinds of cells or many different hosts.
All types of organisms are susceptible to some virus.

Viral Shapes

Viruses can be classified by virion shape.
Three basic types of viral shapes are helical, polyhedral (icosahedral), and complex.
Examples of viral shapes include Tobacco mosaic virus (helical), polyhedral (common cold), and complex (Rabies virus and bacteriophage T4).

Definition of a Virus

A virus is a package of genetic information protected by a protein shell for delivery into a host cell to be expressed and replicated.
The term "virus" comes from the Greek word for "poison" and was initially described by Edward Jenner in 1798.

Characteristics of Viruses

Viruses are minuscule, acellular, infectious agents having either DNA or RNA.
Viruses cause infections of humans, animals, plants, and bacteria.
Viruses cause most of the diseases that plague the industrialized world.
Viruses cannot carry out any metabolic pathway, grow, respond to the environment, or reproduce independently.
Viruses recruit the cell's metabolic pathways to increase their numbers.
Viruses lack a cytoplasmic membrane, cytosol, or organelles.
Viruses are obligate intracellular parasites.

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Description

This quiz covers the different ways viruses are named and classified, including by disease association, cyto-pathology, site of isolation, and discovery history.