Question

Describe how an RNA virus invades and destroys a cell. b. How does this differ from a DNA virus?

Answer 1

a)  In RNA Virus the RNA genome does not require any secondary or tertiary fold in their compound. They are highly organized & tightly packed. The viral genomic RNA is arranged in the icosahedral in various ways to neutralize the negative charges of the nucleic acids.

The positive strand RNA virus transfer its genome directly to the ribosomes & starts translation for the synthesis of viral proteins. The genomic RNA uncoats after getting into the cytoplasm of the infected cells.The RNA is then translated into the viral polyprotein precursor which are later cleaved by proteolysis to form structural& non-structural viral protein. The structural proteins are involved in the maturation & assembly of the virion while non structural act as RNA replicating enzyme for genomic RNA synthesis.

b) Difference b/w DNA &RNA Virus:

I) DNA viruses are mostly double stranded while RNA viruses are single stranded.

II) RNA mutation rate is higher than DNA mutation rate.

III) DNA replication takes place in nucleus while for RNA it is in the Cytoplasm.

IV) RNA viruses are stable while DNA viruses are unstable.

V) In DNA Virus viral genetic code is injected in host DNA for duplication & decoding while RNA virus skip both steps

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