Скачать или смотреть PARASITIC NATURE OF VIRUS, Virus and Host Lec # 07 , Ch # 05

Viruses are obligate intracellular parasites, meaning they depend on a host cell for their replication. They lack the metabolic machinery to replicate independently and rely on the host's resources to synthesize their components. This dependency is the basis of their parasitic nature. Furthermore, viruses exhibit host specificity, meaning they are typically restricted to infecting certain host types, such as plants, animals, or bacteria, and even specific tissues or cell types within those hosts. This specificity is determined by the interactions between the virus and the host, including selective susceptibility of cells, physical barriers, and host defenses.
Parasitic Nature:
Obligate Intracellular Dependence:
Viruses are unable to replicate outside of a host cell. They need the host's cellular machinery for energy production, protein synthesis, and nucleic acid replication.
Resource Exploitation:
Viruses hijack the host cell's resources to produce viral components, often at the expense of the host's own function. This can lead to cell damage and disease.
Host-Dependent Replication:
The virus's life cycle is completely dependent on the host's cellular processes, making them obligate parasites.
Host Specificity:
Selective Susceptibility:
Some cells are more susceptible to infection than others, leading to viral tropism or preference for specific tissues or cell types within the host.
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