Final answer:
Prions are infectious particles composed entirely of proteins and contain no nucleic acids. They are smaller than viruses and can replicate by converting normal proteins into the infectious form.
Step-by-step explanation:
Prions are infectious particles that contain no nucleic acids. They are composed entirely of proteins and are smaller than viruses. Prions are able to replicate by converting their normal protein counterparts into the misfolded, infectious form. The pioneering work of biologist Stanley Prusiner has provided evidence of the existence of prions