Which statement correctly contrasts prions with viruses?

• A. Prions are infectious proteins without nucleic acids; viruses have DNA or RNA.
• B. Prions are alive; viruses are not.
• C. Prions are bacteria; viruses are viruses.
• D. Prions are viruses.

Answer: (A)

Prions and viruses differ in their genetic material. Prions are infectious proteins that lack any nucleic acids, so they don’t carry genetic information or encode how to replicate. They propagate by converting normal prion proteins in the host into the abnormal form, spreading through protein misfolding rather than genetic instructions. Viruses, on the other hand, contain DNA or RNA and rely on infecting a host cell to reproduce, using the host’s machinery to copy their genome and produce new viral particles. That fundamental contrast—no nucleic acid in prions versus nucleic acid in viruses—is what makes this statement correct. The idea that prions are alive, that they are bacteria, or that they are viruses conflicts with the known biology: prions aren’t cells or genomes, and viruses do carry genetic material.