Viroids: In 1971, T.O. Diener discovered a new infectious agent that was smaller than viruses and caused potato spindle tuber disease. It was found to be a free RNA; it lacked the protein coat that is found in viruses. The RNA of the viroid was of low molecular weight.
Viroids are infectious agents made of free RNA only, lacking the protein coat that defines viruses. NTA repeatedly tests whether students can distinguish viroids from viruses—the key difference is the absence of a protective protein shell. Students often confuse viroids with viruses or assume all infectious agents must have proteins. Remember: viroids = naked RNA; viruses = RNA/DNA + protein coat. This concept tests your understanding of the hierarchy of infectious agents and is crucial for the Biological Classification unit.
This paragraph was tested 4 times in NEET.
Which of the following is correct about viroids? NEET 2020
Viroids differ from viruses in having NEET 2017
Which of the following statements is wrong for viroids? NEET 2016
Select the wrong statement. AIPMT 2015
MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.