What is the Difference Between Prions and Viroids?

Prions and viroids are both acellular infectious agents, but they differ in their composition, size, and the diseases they cause. Here are the main differences between them:

1. Composition: Prions are composed of only protein molecules, while viroids are composed of single-stranded RNA.
2. Size: Viroids are smaller than viruses, and prions are smaller than viroids.
3. Nucleic Acid: Viroids contain nucleic acid, while prions do not.
4. Protein Components: Viroids do not have protein components, whereas prions are primarily composed of protein.
5. Infections: Viroids infect mostly plants and cause diseases such as citrus exocortis, cucumber pale fruit, and potato spindle tuber. Prions, on the other hand, mainly cause neurodegenerative diseases in mammals, such as Creutzfeldt-Jakob disease, Gerstmann-Straussler-syndrome, and mad cow disease.
6. Resistance: Prions are extremely resistant to chemicals, heat, and radiation, making them difficult to treat or inactivate.

In summary, viroids are small, single-stranded RNA particles that cause plant diseases, while prions are infectious protein particles responsible for transmissible spongiform encephalopathies in mammals.

Comparative Table: Prions vs Viroids

Here is a table comparing the differences between prions and viroids:

In summary, prions are infectious proteins that cause protein misfolding diseases, while viroids are small, circular, single-stranded RNA molecules that cause several plant diseases.