VIRUSES ➢ not considered truly ‘living’ ➢ inert outside t | Dr. Anand Mani Updates and news
VIRUSES
➢ not considered truly ‘living’
➢ inert outside their specific host cell
➢ take over the machinery of the host cell to replicate, killing the host
➢ In addition to proteins, viruses also contain genetic material- RNA or DNA
➢ viruses that infect plants have single stranded RNA
➢ that infect animals could be either single or double stranded RNA or double stranded DNA
➢ bacteriophages are generally dsDNA viruses
➢ The protein coat called capsid made of small subunits called capsomeres.
☆ These capsomeres are arranged in helical or polyhedral geometric forms.
➢ Diseases in animals- mumps, small pox, herpes and influenza.
➢ Symptoms in plants- mosaic formation, leaf rolling and curling, yellowing and vein
clearing, dwarfing and stunted growth
VIROIDS
➢ Smaller than viruses
➢ Low molecular weight RNA and no protein coat
➢ Potato spindle tuber disease is caused by potato spindle tuber viroid
