Nevada Esthetics State Board License Practice Exam

Viruses are fundamentally different from bacteria in that they require a host to replicate. This is a defining characteristic because viruses cannot reproduce independently; they must invade the cells of a host organism where they hijack the host's cellular machinery to create copies of themselves. This dependency on a host’s cells for replication distinguishes viruses from bacteria, which are single-celled organisms capable of reproducing on their own in suitable environments.

The other options do not accurately describe viruses in comparison to bacteria. For instance, viruses are generally much smaller than bacteria, which contradicts the idea that they are larger. Additionally, while some viruses can exist in an inactive state outside a host, they do not survive in the same way that bacteria can, which are able to thrive and multiply in various environments. Finally, not all viruses can infect skin cells directly; their specificity for host cells varies widely among different virus types.