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NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Smaller than a virus? 
Name: Aelea
Status: Student
Age: 14
Location: N/A
Country: N/A
Date: November 2003
Question:
Are there any other organisms that are smaller or simpler than a virus?


Replies:
Not really. A case might be made for a prion, but that gets into the semantic issue of what you want to call an organism.

Paul Mahoney

Well, that depends whether you think viruses are organisms or not, because not all scientists agree! But let's say they are for argument's sake. There are smaller "infectious particles." Viroids are naked RNA that seem to be associated with disease. And prions are abnormal proteins that seems to be able to induce normal proteins to become abnormal. An example of this would be Mad Cow disease. Do a search for prions and you will find a lot of information.

Van Hoeck

Actually...viruses are not considered "organisms" in the sense that they metabolize on their own. There are some bacteria that approach the size of larger viruses but viruses are smaller than bacteria. They were originally classes as non-filterable organisms because they would pass through filters that would remove bacteria.

pf


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