Am 14.01.2011 16:57, schrieb Invisible:

> I'm
> not sure at what point this system would have acquired a "cell
> membrane", but such as the obvious advantage of concentrating the
> nucleotides synthesized next to the RNA strands that want to use them.

There's a theory that "cell membranes" would have existed even before 
self-replicating stuff: With the chemical composition of the atmosphere 
back then, rain drops might have been covered with a layer of naturally 
occurring molecules with both a hydrophobe and a hydrophile end, forming 
cells in which life might have started.

> So what roles does RNA play today? Well, most obviously, every single
> piece of DNA to be turned into protein has to be turned into RNA first.
> Oh, and the thing that turns RNA into protein? It's made of protein and
> RNA. (And the "active site" itself is RNA. The protein components just
> hold it together.)

AFAIK viruses, too, commonly use RNA.

Maybe the first life can be thought of as a bunch of different ribozymes 
entering a symbiosis.

In that sense, viruses would be the oldest type of life.

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