What is a prion?

What is a prion?

• A. Prions: proteinaceous infectious particle.
• B. Prions: lipid-coated vesicles.
• C. Prions: nucleic acid-based viruses.
• D. Prions: carbohydrate polymers.

Answer: (A)

Prions are infectious proteins that have no nucleic acid. The description "proteinaceous infectious particle" captures this exactly: prions are not viruses or bacteria with genomes; they are misfolded proteins that propagate by inducing normal host proteins to adopt the same misfolded shape. This misfolding causes progressive brain damage seen in transmissible spongiform encephalopathies such as scrapie in animals and Creutzfeldt-Jakob disease in humans. Since prions lack nucleic acids and are not lipid-coated particles or carbohydrate polymers, the other descriptions don’t fit.

Prions are infectious proteins that have no nucleic acid. The description "proteinaceous infectious particle" captures this exactly: prions are not viruses or bacteria with genomes; they are misfolded proteins that propagate by inducing normal host proteins to adopt the same misfolded shape. This misfolding causes progressive brain damage seen in transmissible spongiform encephalopathies such as scrapie in animals and Creutzfeldt-Jakob disease in humans. Since prions lack nucleic acids and are not lipid-coated particles or carbohydrate polymers, the other descriptions don’t fit.