What are the similarities and differences between viroids and prions?

Viroids:

1. The simplest form of the virus that is a plant pathogen is viroids.
2. It is a single-stranded molecule with small in size.
3. Viroids have about 250-370 nucleotides in RNA molecules.

Prions:

1. Prions are infectious agents, which are reasons for neurodegenerative diseases in mammals.
2. It is composed of sialoglycoprotein (sialic acid and glycoprotein combination) and no nucleic acid present.

Similarity:

1. Viroids and prions are acellular in nature.

Difference:

1. Viroids are infectious RNA molecules whereas prions are infectious protein particles.
2. Viroids are smaller than viruses whereas prions are smaller than viroids.
3. Viroids are more complex whereas prions are less complex.
4. The nucleic acid is present in viroids and absent in prions.
5. Viroids are infectious RNA molecules, whereas prions are misfolded proteins.