NOCTI Small Animal Science Practice Exam

Viruses require a host cell to replicate, while bacteria can live and reproduce independently. This is a key distinguishing feature between the two. Viruses are essentially non-living entities that lack the cellular machinery necessary for metabolic processes and reproduction. They must invade a host cell and hijack the host's cellular mechanisms to replicate and produce new virus particles. In contrast, bacteria are living organisms that possess the necessary cellular structures to carry out metabolic functions and reproduce on their own, making them capable of surviving in various environments without dependence on a host.

This fundamental difference highlights the nature of viruses as parasitic entities, which fundamentally influences how they interact with living organisms, the treatment of viral infections compared to bacterial infections, and their role in disease.