Are viruses alive?

Sun Nov 5 13:26:51 EST 1995

Mick (mickj at wrote:
: A recent disucussion into the nature of life and, specifically, viruses
: made me wonder if a virus is alive. Since a virus can lie dormant for
: extremely long periods of time and then begin replicating itself in the
: presence of a host, is it, indeed, in "control"? Is it replicating itself
: or is the host replicating it? Is the fact that a virus may be carried by
: one species with no deleterious effects because that carrier hasn't the 
: proper raw materials to allow or instigate replication? Also, in a species
: where the virus is harmful or even fatal, does it stop because the virus
: has run out of "fuel" or, if the host is in control, because it no longer
: has the ability to continue supplying either energy or raw materials?

: I have no background in biology so I apologize if my questions are
: ridiculous.
I believe your question is still being debated.  Those who argue that 
viruses are "alive" point to the fact that they carry nucleic acid.  
Those who say that viruses aren't "alive" point to the fact that they 
only carry one type of nucleic acid (DNA or RNA but never both), they do 
not possess organelles, and they are wholly dependent upon host cells for 
processing macromolecules and for reproduction.  
I believe viruses, like most pathogens, seek an equilibrium in infection 
with their host because it is not in their best interest to kill off all 
suseptible carriers (otherwise the virus disappears too).  Viruses don't 
consume fuel as cells do--they utilize cellular mechanism for 
reproduction--often speeding up or slowing down the cell's metabolism to 
suit the virus' need.  
I don't know if I answered any of your questions but hope I did!
Matt Wettlaufer

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