Introductory Microbiology

Structure of virions

• The structure of virus varies to spherical, rod, complex structures and the size of virus is in nanometers (nm). The size ranges from 20-200nm. Ex: small pox virus – 200nm, poliovirus – 28nm.
• The genome size of each virus also varies. Herpes virus – Ds DNA-150 kbp, Polio virus – SsRNA-7kbp and Cowpea mosaic virus – ss RNA-9 kbp.
• The nucleic acid of viron is always located within in the particle and surrounded by protein coat called capsid. The protein coat is always formed of a number of individual subunits referred as capsomers. Capsomers are arranged in a precise or highly respective pattern around the nucleic acid.