The reproduction of viruses (virions) necessarily occurs inside a cell (host), so they are considered parasites mandatory intracellular cells, requiring the use of cell structure: genetic material and organelles, for their multiplication and propagation.
For the study and understanding of the reproduction of DNA viruses, it is common to refer to the mechanism of infestation caused by bacteriophages, viruses that attack bacteria (prokaryotes).
The viral infestation process begins with the chemical recognition of fibers present in the virus tail, adhering to the plasma membrane of the host cell. The fibers then contract, allowing the introduction of viral DNA into the cell, with the capsid ("head" of the virus) and tail detached from the outer surface.
After penetration, the genetic material of the virus, conjugated to the bacterial circular DNA, starts to command the metabolic activities as a result of the inactivation of the infected cell's gene command, splitting the chromosome bacterian. For this inability to recognize, the virus uses enzymes from the cell itself, taking control of functional reactions. This makes them, by comparison, true cellular pirates.
From that point on, all transcription synthesis is directed towards the production of new viruses. This is the period of biosynthesis, when the viral DNA will determine the synthesis of the viral components: the capsid and the other structures of the tail.
Proliferation continues with the stage of maturation and release of new viruses, that is, the actual assembly of virions in the interior of the host, with the rupture of the bacterial wall, by the action of digestive enzymes, releasing them to restart the cycle of infestation.
The cycle has an average duration of 30 minutes, marked from the moment of adhesion and introduction of the DNA viral, until the moment the bacterial membrane wall breaks, propagating dozens of new virions.
The reproduction of DNA viruses basically occurs through two types of cycles: the lytic cycle and the lysogenic cycle. However, in the lytic cycle the host cell is destroyed, while in the lysogenic cycle the host is preserved.
By Krukemberghe Fonseca
Graduated in Biology
Source: Brazil School - https://brasilescola.uol.com.br/biologia/reproducao-dos-virus-dna.htm
