NEET BIOLOGY

Detailed explanation-1: -viroid, an infectious particle smaller than any of the known viruses, an agent of certain plant diseases. The particle consists only of an extremely small circular RNA (ribonucleic acid) molecule, lacking the protein coat of a virus.

Detailed explanation-2: -Viroids are tiny single-stranded circular RNA pathogens that infect plants.

Detailed explanation-3: -Viroids are single-stranded, covalently closed, circular, highly structured noncoding RNAs that cause disease in several economically important crop plants.

Detailed explanation-4: -7.2 Viroids Are Naked Molecules of Infectious RNA. Viroids are infectious agents that consist only of naked RNA without any protective layer such as a protein coat. Viroids infect plants (but no other forms of life) and are replicated at the expense of the host cell.

Detailed explanation-5: -The only human disease known to be caused by a viroid is hepatitis D. This disease was previously ascribed to a defective virus called the delta agent. However, it now is known that the delta agent is a viroid enclosed in a hepatitis B virus capsid.