Question

Pick out the statement that does not apply to viroids.

• A. Infectious agents smaller than viruses
• B. Cause potato spindle tuber disease
• C. Have free DNA
• D. Lack protein coat
• E. Discovered by T.O. Diever

Answer 1

The correct option is C Have free DNA

Viroids are the smallest infectious pathogens known. They are composed solely of a short strand of circular, single-stranded RNA that has no protein coating. All known viroids are inhabitants of higher plants and most cause diseases.

Viroids were first discovered by T.O. Diener in the year 1971.

The Potato spindle tuber viroid ("PSTVd") was the first viroid to be identified which cause potato spindle tubes disease.

So the correct answer is option C.