Host specificity of a virus is primarily determined by which of the following factors?

• A. The presence of plasmids in the host cell
• B. The interaction between viral surface proteins and specific host cell receptors
• C. The metabolic rate of the host cell
• D. The ability of the virus to undergo binary fission

Answer: (B)

Verified step by step guidance

1. Understand that host specificity refers to the ability of a virus to infect particular host cells or organisms.
2. Recognize that viruses must attach to host cells to initiate infection, and this attachment is mediated by interactions between viral surface proteins and specific receptors on the host cell membrane.
3. Note that the presence of plasmids in the host cell is unrelated to viral host specificity, as plasmids are extra-chromosomal DNA elements mainly involved in bacterial genetics.
4. Understand that the metabolic rate of the host cell does not determine whether a virus can infect it; rather, it affects viral replication efficiency after entry.
5. Recall that viruses do not undergo binary fission; this is a method of reproduction for bacteria, so it is not relevant to viral host specificity.