What is the structure of the tobacco mosaic virus?
Tobacco mosaic virus (TMV; Tobamovirus, Virgaviridae) is a rodlike virus with a length of 300 nm and diameter of 18 nm. TMV capsids are composed of 2130 identical protein subunits, which assemble around the viral ssRNA to form a helical structure, with a hollow central cavity of 4 nm diameter.
What are the characteristics of tobacco mosaic virus?
mosaic pattern of light and dark green (or yellow and green) on the leaves. malformation of leaves or growing points. yellow streaking of leaves (especially monocots) yellow spotting on leaves.
How many capsids are there in TMV?
2,130
TMV is a simple rod-shaped helical virus consisting of single-stranded RNA enveloped by a protein coat called capsid. This capsid is made of 2,130 sub units called capsomeres. There are 49 capsomeres on every three turns of the helix. So, the correct answer is ‘2130’.
What are the 6 phases of replicative growth of viruses?
Viral replication involves six steps: attachment, penetration, uncoating, replication, assembly, and release. During attachment and penetration, the virus attaches itself to a host cell and injects its genetic material into it.
How is a virus structure?
Viral Structure. In the simpler viruses the virion consists of a single molecule of nucleic acid surrounded by a protein coat, the capsid; the capsid and its enclosed nucleic acid together constitute the nucleocapsid. In some of the more complex viruses the capsid surrounds a protein core (Fig.
What is the shape of TMV capsid?
Tobacco mosaic virus has a rod-like appearance. Its capsid is made from 2130 molecules of coat protein and one molecule of genomic single strand RNA, 6400 bases long.
What are capsids made of?
(A) Virus capsids are composed of viral protein subunits that form structural units.
What are the 5 stages of virus replication?
Main steps of viral replication These include attachment, penetration, uncoating, replication, assembly, and virion release.
What are the 2 main structures of bacteriophage?
The (S/R) form of bacteria caused disease in mice. A bacteriophage has two main structures: a DNA molecule and a — coat. In their first experiment, Hershey and Chase tagged bacteriophages with — sulfur. In their second experiment, Hershey and Chase tagged bacteriophages with — phosphorus.
What is the structure and function of bacteriophage?
Bacteriophage Structure The bacteriophage consists of a polyhedral head, a short collar and a helical tail. Head- The head consists of 2000 capsomeres with double-stranded DNA enclosed within. Tail- The tail consists of an inner hollow tube which is surrounded by a contractile sheath with 24 annular rings.
What are the 4 structures of viruses?
All viruses contain nucleic acid, either DNA or RNA (but not both), and a protein coat, which encases the nucleic acid. Some viruses are also enclosed by an envelope of fat and protein molecules. In its infective form, outside the cell, a virus particle is called a virion.
Does tobacco mosaic virus have a helical capsid?
Tobacco mosaic virus, arenaviruses, and bunyaviruses are some examples of viruses with a helical capsid.
What is the structure of virus?
What is the structure of capsid?
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 is capsid function?
A primary function of the capsid is to protect the viral genome from environmental conditions and ultimately to deliver the genome to the interior of a homologous host cell.
What is bacteriophage and its structure?
A bacteriophage is a virus that infects a bacterial cell and reproduces inside it. They vary a lot in their shape and genetic material. A bacteriophage may contain DNA or RNA. The genes range from four to several thousand. Their capsid can be isohedral, filamentous, or head-tail in shape.
What are the two basic structures 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.