Question

Which of the following is not true of viroids?

1) Viroids are small circular ssRNA molecules.
2) Viroids have no protein capsids.
3) Viroid RNA does not serve as mRNA nor does it direct the synthesis of mRNA.
4) Extracellular viroids have a lipid bilayer envelope.

Answer 1

Viroids are small, single-stranded, circular RNA particles that are much simpler than viruses. They do not have a protein capsid and do not possess a lipid bilayer envelope like some viruses. Viroid RNA does not serve as mRNA nor direct the synthesis of mRNA.

Step-by-step explanation:

Viroids are small, single-stranded, circular RNA particles that are plant pathogens. They do not have a protein capsid and are much simpler than viruses. Viroid RNA does not serve as mRNA nor direct the synthesis of mRNA. Extracellular viroids do not have a lipid bilayer envelope. Therefore, the statement 'Extracellular viroids have a lipid bilayer envelope' is not true of viroids.