> To: virology at net.bio.net> From: david_levy at dfci.harvard.edu (David N. Levy)
> Subject: Re: Viruses vs bacteria
> In article <9510182216.AA27244 at earth.med.pitt.edu>
>bap at MED.PITT.EDU (Bruce Phillips) writes:
> > There are four distinguishing features that are used oroutinely to
> > define viruses as compared to bacteria (prokaryotes) or animal cells
> > (eukaryotes).
> > 1. Viruses, unlike bacteria, etc., do NOT Uuse binary
> > fission to reporoduce.
> > 4. Viruses, unlike bacteria and animal cells, possess only
> > one kind of nucleic acid, DNA or RNA. TIn truth, there is some fuzziness
> > to this attribute, but in general it is true.
...and have the widest range of genomic material (ss and ds RNA and
DNA) and the widest range of genomic replication mechanisms
(semi-cons for DNA, cons and semi-cons for dsRNA, via RNA for DNA and
David N. Levy:
> I would add that (most fundamentally) viruses are always obligate
> intracellular parasites, whereas bacteria are often free living. Also,
> viruses are essentially without endogenous metabolism outside their
> host and are thus considered non-living by many or most biologists or
> at least within a grey area of the definition of "life".
But then, most biologists are not virologists...and anyone with
access to the very excellent Luria et al. "General Virology", 3rd
Edn, will very quickly realise:
a) viruses are DIFFERENT to cellular lifeforms, but no less worthy of
being called alive; and
b) it all depends on what your definitions of "life" and "organisms"
Viruses live OK...!