question_answer 21)

  Difference between virus and viroid is (a) absence of protein coat in viroid, but present in virus. (b) presence of low molecular weight RNA in virus, but absent in viroid, (c) Both (a) and (b) (d)None of the above

Answer:

                  (a) Virus contains DNA or RNA as genetic material and a protein coat, whereas viroids. have no protein coat, but only RNA as their nucleic acid. This is the reason why viroids are carried inside viruses, e.g., hepatitis-D is a viroid that is carried in the capsid of hepatitis-B virus.