1. The tiny, not-so-cute guys that you don’t see coming!

2. 5 How they were discovered:  First observed in degenerative disease Kuru. Discovered and coined by Prusiner 1982. 4 Far to go:  Not much is actually know about prions. Questions such as how do they “replicate” are still unanswered.

3. Examples of diseases caused by prions:  Prions cause neurodegenerative diseases such as: kuru, Creutzfeldt-Jakob, scrapie, and “Mad Cows Disease.”

4. Their structure:  A prion is a protein found mainly in the brain. It is not the protein itself that causes disease but only the abnormally folded version of the prion protein also know as an infectious prion.

5. How they work:  The infectious prion is somehow capable of inducing of prion proteins to adopt an abnormal configuration. These abnormal proteins cannot be destroyed by lysosomes and they accumulate to cause cell and spongy degeneration of the brain.

6. 5 Discovery:  Considered a major biological breakthrough when discovered by pathologist, Diener, 1971. 4 Classification:  Viroids have been classified into two families, three sub- families, and eight genus and species groups. There are still many unclassified viroids.

7. Diseases caused by viroids:  Viroids are primarily associated with plants. Viroids are responsible for crop diseases such as potato spindle tuber, avocado sunblotch, etc. Recently however, it is found that a certain type of viroid plays a role in human hepatitis D.

8. Structure:  Viroids are 80 times smaller than normal viruses; formed without a protein coat. Contains short circular RNA strands, but does not encode for any protein products in their structures.

9. How they work:  When a viroid enters the host cell it takes over RNA polymerase and produces copies of itself. In this manner it can quickly spread and grows to numerous numbers within a cell before breaking out and spreading to other cells.

10. Pictures In order:  http://www.nickcampos.com http://www.nickcampos.com  http://student.biology.arizona.edu http://student.biology.arizona.edu  http://pubs.acs.orghttp://pubs.acs.org  http://plantdiseasehandbook.tamu.edu http://plantdiseasehandbook.tamu.edu  http://schaechter.asmblog.org http://schaechter.asmblog.org  http://thevirologyblog.blogspot.cahttp://thevirologyblog.blogspot.ca Text Reference  http://www.atsu.edu/faculty/chamberlain/Website/Lects/PRIONS.HTM http://www.atsu.edu/faculty/chamberlain/Website/Lects/PRIONS.HTM  http://www.els.net/WileyCDA/ElsArticle/refId-a0000434.html http://www.els.net/WileyCDA/ElsArticle/refId-a0000434.html  Audesirk T., Audeesirk G., Byers B. 2008, Pearson Prentice Hall, Pearson Education, Inc, Upper Saddle River, NJ Biology Life on Earth with Physiology pp381-385.  http://mcmanuslab.ucsf.edu http://mcmanuslab.ucsf.edu  http://www.cdc.gov http://www.cdc.gov  http://www.news-medical.net http://www.news-medical.net