PSI Barbering Practice Exam

What type of pathogens can only replicate by invading a host cell?

1. Bacteria

2. Viruses

3. Fungi

4. Protozoa

The correct answer is: Viruses

Viruses are unique among pathogens because they cannot replicate on their own. Instead, they must invade a host cell to reproduce. Once a virus enters a host cell, it hijacks the cellular machinery to create copies of itself, often causing harm to the host cell in the process. This inability to replicate independently distinguishes viruses from other types of pathogens like bacteria, fungi, and protozoa, which can grow and multiply without requiring a host cell. Bacteria are single-celled organisms that can reproduce through binary fission and do not require host cells to multiply. Fungi can grow and reproduce independently through spores or budding. Protozoa are also single-celled organisms capable of reproducing on their own through various methods such as binary fission or sexual reproduction. Therefore, the characteristic of needing a host cell for replication solely applies to viruses.