68W Limited Primary Care (LPC) Practice Exam

Viruses function by invading host cells and hijacking the host's cellular machinery to replicate themselves. They do not have the necessary structures or metabolic processes to produce proteins or generate energy independently, which is why they must rely on the host's systems. Once inside the host, a virus injects its genetic material and takes control of the host's ribosomes, using them to synthesize viral proteins and replicate its genetic material. This allows the virus to produce many copies of itself, which can then go on to infect other host cells.

This dependency on a host for replication and protein synthesis is a defining characteristic of viruses, setting them apart from other microbiological entities that can live and reproduce independently.