What is the kind of virus that infects bacteria called?

• A. Bacteriophage
• B. Retrovirus
• C. Adenovirus
• D. Poxvirus

Answer: (A)

Viruses that infect bacteria are called bacteriophages. The name literally means “bacteria eaters,” reflecting their specific bacterial hosts. Phages attach to bacterial surfaces, inject their genetic material, and use the bacterial machinery to replicate, often causing the cell to burst in a lytic cycle or integrating into the genome in a lysogenic cycle. This host range distinguishes them from other viruses. A retrovirus infects animal cells and carries reverse transcriptase to convert RNA to DNA, so it targets animals rather than bacteria. Adenovirus and poxvirus are also animal viruses that infect vertebrates, not bacteria. So bacteriophage is the correct term for a virus that infects bacteria.