Prebiotic chemistry and origins of life (continued)...

[KennyR]

The amino acid code for the simplest self-replicating molecule than can be thought up is Lee's peptide:

RMKQLEEKVYELLSKVACLEYEVARLKKLVGE

Where each letter corresponds to an amino acid. This is the best that theorists can come up with, and it's pretty simple. It is probably impossible to find simpler self-replicating molecules.

So supposing you had a system that allowed peptides to form and join up, which no naturally existing non-bioligical system today allows (because water and oxygen in excess don't favour peptide bonding - ask Karlos).

There are about 2000000000000000000000000000000000 different ways of forming a polypeptide that are exactly 32 long like the one above. Only one way will make that self-replicator.

Even if the earth was 20 times the size and covered by one huge "warm pond", this would not happen by chance. Clearly, pre-biotic chemistry has a long way to go.

The answer of course is probably that it's not by chance, and that some symmetry inhereted from the quantum fluff that makes up the foundation of the universe favours life. In fact, there's no doubting it: it does, or we wouldn't exist.

This in itself does not disprove the engineering of a higher power. Some would even say it proved it.

[KennyR]

bjjones wrote:
They all three basically refer to the discovery of red blood cells within a partially fossilized T-Rex bone. The first seeks to support it, the second seeks to disprove it, and the third is sort of neutral and just talks about it. What is interesting to me though is that none of the three denies that there is unfossilized bone tissue there. This tissue could give us a better understanding of the biochemical makeup of these extinct reptiles, especially if the DNA strands in the nuclei are intact. I wonder if these dinosaurs have been extinct for as long as it has been estimated.

One problem - red blood cells have no nuclei and no DNA! :-(

[KennyR]

Cymric wrote:
However, I draw the line at 'something inherited from the quantum fluff that makes up the foundation of the universe' for an explanation. We are dealing with chemistry, not with the space-time continuum (or if you prefer, quantum foam.) Okay, if you insist, then I admit that chemistry is an exceedingly low-energy manifestation of it.

It's more than that. It's structures in the quantum world that actually define chemistry. They ARE chemistry! Matter and its chemical interactions are just an expression of this quantum world. Change any tiny part of the underlying structure and perhaps neutrons wouldn't be stable, or electrons would have 100000 times the mass.

Just as quantum physics "just happened" to be perfect for physics, which allowed chemistry, which allowed biology. The formation of life, through whatever means, was as predetermined as the formation of quarks, protons, and atoms.

And every chemical reaction too, involves quantum physics directly. When molecules react, they don't do it like lego or clockwork. At the instant of a reaction, they exist in a quantum superstate, where simultaneously all of the possible products of the reaction exist, until something causes the quantum state to break down. Usually the most probable product of the reaction finishes up.

Chemists should already be familiar with quantum superstates via the benzene molecule. I was taught in high school that benzene constantly swaps its pi and sigma bonds. However it was also known for years that this does not fit what we observe of its properties. Chemists found out later that  all the possible configurations of the kekule ring structure exist at once. It's the same properties of conjugated bonds that allow some polymers to conduct electricty. Neither of these phenomena are chemical, both are quantum.

In the same way, it's possible that all 2000000000000000000000000000000000 polypeptides existed at once, and some underlying symmetry made it more likely for our self-replicator to form. Well, it's not so far-fetched; it was the same kind of "bias" in the quantum world that allowed matter to gain the upper hand over antimatter.

What predetermined life? We could go for the anthropomorphic theory and decide that this was by total chance that, among an infinite number of infinitely varying universes, ours was special and allowed the creation of self-replicator - simply because if it hadn't, we wouldn't be here to see it. Or we could go running to God. Either way is just as useless at the moment, but there is no doubting that our universe was destined to develop life the moment it was created. We just have to find out how it did it, and what "its method" was. Why is better left to philosophy.