GENERAL MORPHOLOGY Viruses may be classified into several morphological types on the basis of their capsid architecture as revealed by electron microscopy and a technique called X-ray crystallography
Viruses may be classified into several morphological types on the basis of their capsid architecture as revealed by electron microscopy and a technique called x-ray crystallography. GENERAL MORPHOLOGY
A. Some viruses. such as tobacco mosaic virus, have a helical symmetry with the capsid surrounding an RNA genome B, Many viruses that infect bacteria, such as the T-even bacteriophage, have a complex LR&A capsid with DNA contained within the head structure C. Some animal viruses such as adenovirus have isometric symmetry and a dna genome D, others, such as coronavirus(冠状病毒) have complex capsids and an envelope with protruding proteins surrounding an RNa genome
A, Some viruses, such as tobacco mosaic virus, have a helical symmetry with the capsid surrounding an RNA genome. B, Many viruses that infect bacteria, such as the T-even bacteriophage, have a complex capsid with DNA contained within the head structure. C, Some animal viruses, such as adenovirus, have isometric symmetry and a DNA genome. D, others, such as coronavirus(冠状病毒）, have complex capsids and an envelope with protruding proteins surrounding an RNA genome
helical viruses Helical viruses resemble long rods that may be rigid or flexible. Surrounding the nucleic acid, their capsid is a hollow cylinder with a helical structure. An example of a helical virus that is a rigid rod is the tobacco mosaic virus
Helical viruses resemble long rods that may be rigid or flexible. Surrounding the nucleic acid, their capsid is a hollow cylinder with a helical structure. An example of a helical virus that is a rigid rod is the tobacco mosaic virus Helical viruses
Polyhedral viruses The capsid of most polyhedral viruses is in the shape of a regular polyhedron with 20 triangular faces and 12 corners The capsomeres of each face form an equilateral triangle. An example of a polyhedral virus in the shape of an icosahedron is the adenovirus Another icosahedral virus is the poliovirus
The capsid of most polyhedral viruses is in the shape of a regular polyhedron with 20 triangular faces and 12 corners. The capsomeres of each face form an equilateral triangle. An example of a polyhedral virus in the shape of an icosahedron is the adenovirus. Another icosahedral virus is the poliovirus. Polyhedral viruses
Enveloped viruses Narr id Evelope The capsid of some viruses is covered by an envelope Enveloped viruses are roughly spherical but highly variable in shape because the envelope is not rigid. When helical or polyhedral viruses are enclosed by envelopes, they are called enveloped helical and enveloped polyhedral viruses. An example of an enveloped helical virus is the influenza virus
The capsid of some viruses is covered by an envelope. Enveloped viruses are roughly spherical but highly variable in shape because the envelope is not rigid. When helical or polyhedral viruses are enclosed by envelopes, they are called enveloped helical and enveloped polyhedral viruses. An example of an enveloped helical virus is the influenza virus. Enveloped viruses