Prions are infectious particles that contain no nucleic acids, and viroids are small plant pathogens that do not encode proteins.

Do viroids have DNA or RNA?

Viroids are the smallest pathogenic agents yet described. They are single-stranded circular RNA molecules which vary in length from 246 to 463 nucleotides and are found only in plants.

What are viroids made of?

Viroids are infectious agents composed solely of circular single-stranded RNA which folds over on itself to form some double stranded regions. These are catalytic RNAs (ribozymes). 9. The viroid RNA codes for a single protein, the delta antigen.