Viruses are defined as ...

Viruses are defined as ...

• A. Tiny particles smaller than bacteria that must invade living cells to reproduce
• B. Large organisms that can be seen with the naked eye
• C. Living cells that produce toxins
• D. Fungi that cause infections

Answer: (A)

Viruses are tiny particles smaller than bacteria that must invade living cells to reproduce. They lack their own cellular machinery and metabolism, so they cannot replicate outside a host cell; they hijack the host’s enzymes and genetic tools to make more virus particles. Because of this, viruses are inert outside living cells and rely on infection of a cell to propagate. In infection control, this understanding helps explain why surface disinfection and hand hygiene are crucial, since stopping transmission depends on inactivating viruses on surfaces and preventing their entry into new host cells. The other descriptions don’t fit viruses: they are not large organisms visible to the naked eye, they are not living cells that produce toxins, and they are not fungi.

Viruses are tiny particles smaller than bacteria that must invade living cells to reproduce. They lack their own cellular machinery and metabolism, so they cannot replicate outside a host cell; they hijack the host’s enzymes and genetic tools to make more virus particles. Because of this, viruses are inert outside living cells and rely on infection of a cell to propagate. In infection control, this understanding helps explain why surface disinfection and hand hygiene are crucial, since stopping transmission depends on inactivating viruses on surfaces and preventing their entry into new host cells. The other descriptions don’t fit viruses: they are not large organisms visible to the naked eye, they are not living cells that produce toxins, and they are not fungi.