Viroids and Viruses

Viroids are

Viroids have

Viroids have

Write a brief account of viroids and prions.

Viroids are different from viruses w.r.t :

Read the following statements and select the option which CORRECTLY identifies the INCORRECT ones. (i) Potato spindle tuber disease is caused by viroids . (ii) Viruses cause diseases like common cold, herpes and AIDS. (iii) Mycoplasma is prokaryotic organisms that completely lack a cell wall. (iv) In Ascomycetes, the asexual spores are conidia produced endogenously on the special mycelium called conidiophores

[A] : Subviral infectious agents are called viroids . [R] : Viroids cause persistent infections .

Viruses are

All viruses

Viroids discovered by Diener (1971) are infectious agents and cause diseases in plants only. They differ from viruses in being