PATHOLOGY

Detailed explanation-1: -Viruses cannot reproduce outside a living cell because they lack the cellular organisation and independent machinery which is required for the reproduction and other metabolic activities. They can only multiply inside the living cell of host by using host’s cellular machinery.

Detailed explanation-2: -They do not possess ribosomes and cannot independently form proteins from molecules of messenger RNA. Because of these limitations, viruses can replicate only within a living host cell. Therefore, viruses are obligate intracellular parasites. According to a stringent definition of life, they are nonliving.

Detailed explanation-3: -Viruses cannot replicate on their own, but rather depend on their host cell’s protein synthesis pathways to reproduce. This typically occurs by the virus inserting its genetic material in host cells, co-opting the proteins to create viral replicates, until the cell bursts from the high volume of new viral particles.

Detailed explanation-4: -All viruses are obligate parasites; that is, they lack metabolic machinery of their own to generate energy or to synthesize proteins, so they depend on host cells to carry out these vital functions. If an obligate parasite cannot obtain a host it will fail to reproduce. Q.