Question

imporant details about viruses ?

Answer 1

Viruses are one of the tiniest infectious agents. They are nothing but nucleoproteins. They contain nucleic acid under covering of proteins of different shapes. They are parasites at genetic level. They manipulate the cellular machinery of host and force it to synthesize the viral components.

i. Viruses are alive only inside the host.

ii. Viral replication happens inside host only.

iii. They remain dormant outside the host.

iv. Viral genome remains inside capsid, which is made up of proteins The monomeric unit of capsid is known as capsomere..

v. Some times they also contain an additional lipid layer. The lipid layer is result of budding from host cells at the time of release after completion of infection cycle

vi. Some additional spikes, made up of protein are also present in some viruses.(Coronaviridae)

vii. Shape of viruses can be diverse ranging from spherical (HIV), rod shaped (TMV) to bullet shaped rhabdovirus

viii. Host range is also quite diverse. They infect nearly each class of organism ranging from bacteria, mycoplasma plants and animals

ix. Genome. – They contain either DNA or RNA as genetic material but never both.

Genome can be made up of single stranded DNA- family of microviridae

or double stranded DNA- Family of Adenoviridae

or single stranded RNA- Family of coronaviridae

or double stranded RNA.- Faminy of Picobirnaviridae