Massachusetts State Board Esthetics Practice Exam

What is the primary biological feature that differentiates viruses from bacteria?

1. Viruses reproduce via binary fission

2. Viruses are cellular organisms

3. Viruses require a host to replicate

4. Viruses contain a nucleus

The correct answer is: Viruses require a host to replicate

The primary biological feature that differentiates viruses from bacteria is that viruses require a host to replicate. Unlike bacteria, which are single-celled organisms capable of living and reproducing independently through processes such as binary fission, viruses cannot reproduce on their own. They lack the cellular machinery necessary for metabolism and reproduction, and instead, they must infect a host cell, hijacking the host's cellular machinery to replicate and produce new viral particles. This distinction is foundational in understanding how viruses operate and how they interact with living organisms. For example, once a virus enters a host cell, it can take over the cellular processes, leading to the production of new viruses, which can then infect other cells. This dependency on a living host is critical for viral life cycles, making it a defining characteristic that sets them apart from bacteria, which are capable of independent life.