A couple of things before I start, by way of correction and clarification:
The mRNA passes through the pores in the nuclear membrane, and makes its way to the part of the cell where proteins are made, called the rough endoplasmic reticulum (ER).
This is talking about eukaryotic cells and certainly has little to do with the simple cell-like start to life. It is also quite inaccurate: mRNA does not make its' way to the ER, and the ER is
not where all proteins are made. The same goes to your reference to the nucleus - its' a eukaryotic feature.
ribosome - Protein-making factory of the cell. Made of protein and RNA, ribosomes act as a type of scaffold to coordinate the reading of the DNA code with adding new amino acids to the translated protein chain
I think I need to clarify something I said earlier. The active site of the ribosome, where the peptide bond between two amino acids is formed (ie the business end of the ribosome) is mainly made up of rRNA. How it is catalysed is a bit unclear, but what
is clear is that rRNA plays a major role in
the primary function of the ribosome. A situation where solely RNA could perform this catalysis is not unimaginable by any means.
With this in mind I'd like to add another term to your list:
Ribozyme: a strand of RNA with enzymatic activity.
Now onto the main thrust of your argument:
RNA can't be created without already existing DNA and DNA can't be created without already existing RNA. That was simple. You must agree.
You're making a common creationist mistake by comparing modern (and therefore highly evolved) life with early, "proto-life". Early life was, almost by definition, simple, crude and imperfect. It didn't have to be perfect though, just able to reach what we have now in small steps.
For example, all life now (with the possible exception of RNA viruses - if you count viruses as being 'alive') is based on DNA being the storage molecule, but why did this have to be the case as life began? DNA scores over RNA in many ways as a store of base sequences, but they
are very similar molecules, and RNA could quite easily started out as the storage medium, only to be replaced by the its' more stable cousin. After all, whats an -OH group between molecules?
RNA molecules, as P.S. rightly points out, have been shown to be capable of self-replication. Synthetic RNA strands have even been shown to replicate other RNA molecules
independently of DNA or protein. Again, no code required, just the laws of physics, and selective pressures. Which brings me back, as ever, to the 'universal' genetic code:
Even the genetic code didn't have to pop into existance in its' entirety with the codons for all 20 amino acids intact. One paper I read recently suggested that a 'proto-code' of just 5 or 6 amino acids would be enough to start life off on the protein road.
These amino acids tend to be the most abundant in the Miller primordial soup, all have simple codons (consisting of mostly C's and G's) and are known to be important in the formation of secondary structure in proteins (especially in beta-sheet motifs). Other amino acids with more complex codons, and longer biosynthetic pathways could be integrated at a later time-frame.
This possible step-wise generation of the genetic code suggests to me that a designer is not required.
And finally, regarding your assertion that
Computer = a cell. Program = DNA code
is enough to show that a computer and the origins of life are analogous:
What part of the computer reperesents the replicating, uncoding molecule such as RNA? Which particular bits are the free floating amino acids, or the lipid membranes?
In other words, how exactly can you equate a man-made computer with a primordial soup, the contents and conditions of which we can only make vague guesses at? By the time you've actually made a good stab at evening it up, you end up with something that is nothing like a computer, and so the analogy is meaningless.
And before you reply remember that nobody is saying that the origin of life, as I am describing it, is a cast iron fact. We're just saying that it is possible.
This message has been edited by Ooook!, 08-18-2004 06:55 PM
) but I think I read it correctly. The one bit that I have misread (and will go and correct on my previous message) is that the early codons (for the Miller aas) were GC rich, although not exclusively GC.
™ Version 4.2
