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
with
> 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
life?

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

GS





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