Which organism requires a host cell for replication?

Which organism requires a host cell for replication?

• A. Bacterium
• B. Fungi
• C. Virus
• D. Prion

Answer: (C)

Viruses are obligate intracellular parasites, meaning they must enter a host cell and hijack that cell’s machinery to replicate. They lack the full set of cellular components—such as ribosomes and metabolic pathways—needed to copy their genome and produce viral proteins on their own, so outside a cell they remain inert particles. Bacteria and fungi are cellular organisms with their own replication machinery, so they can reproduce independently. Prions are misfolded proteins that propagate by converting normal proteins to the misfolded form, not by replicating genetic material. Therefore, the virus is the only option that inherently requires a host cell to replicate.

Viruses are obligate intracellular parasites, meaning they must enter a host cell and hijack that cell’s machinery to replicate. They lack the full set of cellular components—such as ribosomes and metabolic pathways—needed to copy their genome and produce viral proteins on their own, so outside a cell they remain inert particles. Bacteria and fungi are cellular organisms with their own replication machinery, so they can reproduce independently. Prions are misfolded proteins that propagate by converting normal proteins to the misfolded form, not by replicating genetic material. Therefore, the virus is the only option that inherently requires a host cell to replicate.