Structure and multiplication of viruses

Structure of viruses

Often the protein comes from a substance consisting of a sheath and a nucleic acid. Protein sheath or capsid can be a complex structure with tail and finger extensions, such as the bacteriophage infecting T4 virus, or in the form of a simple polyhedron or rod (actually a spiral formed by protein molecules, many animal viruses, some plant viruses and very few surrounded by an envelope structure around the bacteriophage envelope, sometimes containing envelope proteins, in addition to capsid and envelope proteins, some viruses (partly retroviruses) are restricted to the envelope proteins have a number of enzymes.
Depending on the genus of the virus, the nucleic acid is a single molecule containing 3500-600,000 nucleotides (some viruses have fewer nucleotides, which can multiply if the host cell is infected by another helper virus) (in some cases, like the influenza virus, , And HIV [AIDS virus] carries two copies of the chromosome). If the average size of a gene is assumed to be 1000 nucleotides, then the total number of genes on a virus can range from five to hundreds.
Viruses are highly variable in terms of nucleic acids. In some, DNA is double-stranded while in others it is a single strand. In some, the DNA is linear, some in an annular configuration. Many viruses are distinguished by having RNA strains from all other cellular organisms. In many cases the RNA is a single-strand but some double-stranded RNA viruses have been identified.

Proliferation of viruses

Viruses can not multiply as many organisms do because they do not have multienzymes, they do not have ATPs and raw materials for synthesis.
It is not the virus itself that gives rise to new viruses; but the host that operates in the direction of his information is the cell. For this reason, viruses can not reproduce in artificial medium, which requires live cells. In many pharmaceutical companies and research laboratories, viruses are often produced in bacteria, in fertilized hen eggs, or in tissue cultures.
The chemical structure of the host cell is used to create a new virus; they leave the cell in the form of budding or bursting together. Others integrate their genetic material into the chromosome of the site or create new roots or, in a drowsy state, expect something to activate themselves. In retroviruses, the RNA genome is transcribed by DNA-reverse transcriptase; This is the DNA version that is combined with the host genome.
Phage is attached to the bacterial cell wall by tail fibrils; When the protein sheath is outside, the nucleic acid is injected into the brain. The energy required for this injection is derived from the hydrolysis of about 140 ATP molecules (all 140 Ca & lt; ++ & gt; ions) in the tail of the phage. In the meantime, phage DNA in the bacterial cell provides the genetic information necessary for the synthesis of new viral DNA and protein.
These synthesized proteins are used not only for viral capsids, but also for the construction of enzymes that will aid in the synthesis and maintenance of viral contents. Meanwhile, after the formation of new viral nucleic acids and proteins, they become new bacteriophages and lyse the phage inducing enzymes by attacking the bacterial cell wall.
Simple viruses are not interested in binding enzymes. Instead, they use one or two types of sheath proteins, which crystallize around the viral genome. This self-regulatory event has been identified in the tobacco mosaic virus, which is spirally sequenced through the 2130-identical protein subunit RNA molecule. (Recent studies have shown that the capsules of this virus can be in the form of two-layer discs and then undergo a conformational change to form such a structure).
Source: poxox.com learn

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