What is Virus?

What is virus?
Virus may be defined as an ultra microscopic disease producing nucleoprotein particle that can multiply only within living organisms.

Virus is Living or Non Living?
Virus is living inside the body while non-living outside the body of an organism.

 Non-living characters of virus:-
1. Viruses are non-cellular entities.
2. Viruses can grow and multiply only in living cells.
3. Viruses have high specific gravity.
4. Viruses do not response to environmental changes.
5. Viruses only bears only one type of nucleic acid i.e DNA or RNA.

Living characters of virus:-
1. All viruses are pathogenic i.e disease producing particles.
2. They show reproduction and multiplication in the living organisms.
3. Viruses are obligate parasites.
4. Viruses exhibit mutations and are of capable of producing new variants.
5. They bear genetic material.
6. They become inactive by treatment of pepsin.
7. Viruses can bring out enzymatic changes in vitro.
8. They respond to temperature, chemicals and radiations.
9. Some viruses undergo incubation period.

If one goes through the non-living  characters of viruses, they can be considered as non-living as non-cellular or acellular. However, they bears many significant living characters. 

Lwoff, a French scientist has rightly said,"It is neither an organism, nor a non-living inert chemical."