There are many different types of viruses that infect humans and other animals, some cause serious diseases and others do not.Viruses can be categorized according to the Baltimore system, and viruses that infect humans fall into their seven categories.The humanoid immunodeficiency virus (HIV), which roots acquired immunodeficiency syndrome (AIDS), is a retrovirus.
Explanation:
Helical
These germs are composed of a single type of capsomer stacked around a central axis to form a helical structure, which can have a central cavity or tube. This arrangement results in rod-shaped or filamentous virions that can be short and highly rigid, or long and very flexible. The inherent material (typically single stranded RNA, but ssDNA in some cases) is bound to the protein helix by interactions between the negatively charged nucleic acid and the positive charges on the protein. In general, the length of a helical capsid is related to the length of the nucleic acid contained therein, and the diameter depends on the size and arrangement of the capsomeres. One of the best explanation is well-studied tobacco mosaic virus is an example of a helical virus.
Prolate
This is an elongated icosahedron along the quintuple axis and is a common arrangement of bacterio phage heads. This structure is composed of a cylinder with a cover on each end.
Envelope
More or less types of viruses are wrapped in a modified form of one of the cell membranes, either the outer membrane surrounding an infected host cell or internal membranes such as the nuclear membrane or the endoplasmic reticulum, thus obtaining an external lipid bilayer known as a viral envelope . This membrane is studded with proteins encoded by the viral genome and the host genome; The lipid membrane and the carbohydrates present originate completely from the host. The influenza virus and HIV use this strategy. Most enveloped viruses depend on the envelope for their infectivity.
Icosahedral
Most animal viruses are icosahedral or almost spherical with chiral icosahedral symmetry. A regular icosahedron is the optimal way to form a closed cover from identical subunits. The least amount of identical capsomeres required for each triangular face is 3, which gives 60 for the icosahedron. Many viruses, such as rotavirus, have more than 60 capsomeres and appear spherical, but retain this symmetry. To achieve this, the capsomeres in the vertices are surrounded by five other capsomeres and are called pentones. The capsomeres on the triangular faces are surrounded by six others and are called hexons. The hexons are essentially flat and the pentons, which form the 12 vertices, are curved. The same protein can act as the subunit of pentamers and hexamers or they can be composed of different proteins.
Genome
You can see a huge variety of genomic structures among viral species; As a group, they contain more structural genomic diversity than plants, animals, archaea or bacteria. Close by millions of dissimilar types of viruses, although only about 5,000 types have been described in detail. As of September 2015, the NCBI virus genome database has more than 75,000 complete genome sequences, but there are undoubtedly many more to discover.
A virus has a DNA or RNA genome and is called a DNA virus or RNA virus, respectively. The vast majority of viruses have RNA genomes. Houseplant germs tend to have single stranded RNA genomes and bacteriophages tend to have double stranded DNA genomes
