Exceptions of living things NOT composed of cells?

Graham Shepherd muhero.nospam at globalnet.co.uk
Tue Jan 27 15:03:22 EST 2004

"Larry D. Farrell" <farrlarr at isu.edu> wrote in message
news:10ae2a538eea189359102c058a8fac24 at news.teranews.com...
> Mark wrote:
> > I guess a good distinction between the viruses and the intracellular
> > bacteria could be reached by considering the source of the replication -
> > viruses are replicated by using the host (by the host), while the
> > bacteria might be considered to be replicated by themselves, but within
> > the host. What do we all think about this?
> >
> > mark
> This is pretty much the point I was trying to make, but apparently did not
do so
> clearly.  Anything that can be "considered to replicate by themselves"
would have to
> have all of the basic mechanisms needed for replication.  Even those
endosymbionts or
> obligate parasites that cannot, at present, be grown in the absence of
their host
> organism do have all of the basic mechanisms but may be lacking the
ability to make
> some specific nutrient/component that the host supplies (ATP, as indicated
in another
> post, would be a perfect example of this).  On the other hand, viruses,
viroids and
> prions clearly do not have those mechanisms and are completely dependent
on the host
> to provide them.  In my opinion, that provides a pretty clear division
between living
> and non-living.  However, one can still argue, as many do, that viruses,
viroids and
> prions are examples of "some type" of life and it is had to refute that
since the
> range of meanings for "some type" is pretty broad.  For me, having worked
> bacterial viruses (phages) for 30 years, viruses are not living but they
are damned
> clever parasites.

I invite you to look at this topic from the wrong end of the telescope - all
the essential information for supporting the replication of one of these
entities is now, or one day will be, in the literature - it will then be
possible to replicate the entity starting from only the information.
Clearly, life IS information, but at what point does information become

BTW, T4 is still my favourite - based entirely on its picture.


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