What is capsid symmetry?

Symmetry refers to the way in which capsomere units are arranged in viral capsid. Two kinds of symmetry are recognized in the viruses which corresponds to two primary shape ie. Rod and spherical shape of virus.

What is the shape of a viral capsid?

Virus capsids predominantly come in two shapes: helical and icosahedral. The helix (plural: helices) is a spiral shape that curves cylindrically around an axis. It is also a common biological structure: many proteins have sections that have a helical shape, and DNA is a double-helix of nucleotides.

What are the 3 shapes of a capsid?

The three basic capsid shapes are icosahedral, helical, and prolate; however, the shape of capsids can vary widely. The capsids are made from capsomeres, or protein subunits.

Does poliovirus have a capsid?

Polioviruses are single-stranded RNA viruses belonging to the family Picornaviridae. They have a naked protein capsid with a dense central core. The capsid consists of four structural proteins, VP1, VP2, VP3, and VP4. The genomic RNA is approximately 7440 to 7500 nucleotides in length.

What types of symmetry are seen in virion capsids?

Virus particles (virions) fall into three main morphological groups characterized by (1) helical symmetry, (2) cubic symmetry, and (3) other symmetries.

Which two viruses infect all the vertebrates?

The family Togaviridae comprises the genera Alphavirus and Rubivirus among the vertebrate viruses.

How does capsid help in classification of viruses?

The simplest virions consist of two basic components: nucleic acid (single- or double-stranded RNA or DNA) and a protein coat, the capsid, which functions as a shell to protect the viral genome from nucleases and which during infection attaches the virion to specific receptors exposed on the prospective host cell.

What is a capsid structure?

A capsid is the protein shell of a virus, enclosing its genetic material. It consists of several oligomeric (repeating) structural subunits made of protein called protomers. The observable 3-dimensional morphological subunits, which may or may not correspond to individual proteins, are called capsomeres.

What shape does the poliovirus have?

Poliovirus is a nonenveloped virus having the shape of an icosahedral capsid (spherical), belonging to the Picornaviridae family. It may cause poliomyelitis (infantile paralysis).

Is poliovirus segmented?

There are three poliovirus serotypes: types 1, 2, and 3. Poliovirus is composed of an RNA genome and a protein capsid. The genome is a single-stranded positive-sense RNA (+ssRNA) genome that is about 7500 nucleotides long….

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