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Pre-Rna World Genetic_Code With Only A Single (But Reversible) Nucleotide


granpa

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A pre-RNA world Genetic_code with only a single (but reversible) nucleotide (or rather nucleobase) which also happens to be an amino acid!
Specifically 3-Aminobenzoic_acid (image below is the Zwitterion form)
In the zwitterion form the acid (COOH) has donated a proton to the base (NH2)

277px-3-Aminobenzoic-acid-zwitterion-nuc

http://en.wikipedia.org/wiki/PAH_world_hypothesisPolycyclic_aromatic_hydrocarbons are the most common and abundant of the known polyatomic molecules in the visible universe, and are considered a likely constituent of the primordial sea. PAHs , along with fullerenes (or "buckyballs"), have been recently detected in nebulae.
PAHs are not normally very soluble in sea water, but when subject to ionizing radiation such as solar UV light, the outer hydrogen atoms can be stripped off and replaced with a hydroxyl group, rendering the PAHs far more soluble in water.
These modified PAHs are amphiphilic, which means that they have parts that are both hydrophilic and hydrophobic. When in solution, they, like lipids, tend to organize with their hydrophobic parts protected. Unlike lipids though, they assemble into a 1 dimensional liquid crystal stack which is similar to, but much smaller than a microtubule (4 vs 256 angstroms)

(microtubules form the nerves and brain of the cell and evolved from endosymbiotic nanobes).

Today there are four different types of nucleobases which stack on top of one another like plates to form the RNA molecule
Perhaps in the original PAH world there was only one type of nucleobase but it could be put on the liquid crystal stack in one of two different orientations by simply flipping it over like a pancake.

I suspect that the original base looked something like this:
https://en.wikipedia.org/wiki/3-Aminobenzoic_acid (see image below of the Zwitterion form)
Note that this would have been both a nucleobase and an amino acid and is technically not a PAH.
It is soluble in boiling water but not in water at room temperature.
It was probably produced by intense lightning in a very thick atmosphere of hydrogen, methane, ammonia, and carbon dioxide.
There was so much lightning that most of the carbon was coverted to reactive compounds that ended up as carbonate rocks.
Attaching a carbohydrate monomer (perhaps originally another 3-Aminobenzoic_acid molecule) to its hydrophobic backside would have greatly increased its solubility in water as the atmosphere thinned and the earth cooled.
In todays cooler and thinner atmosphere lightning is relatively rare.

Eventually liquid crystal PAH 's evolved sugar-phosphate backbones.
The coding strand becoming RNA and the noncoding strand becoming DNA.


https://en.wikipedia.org/wiki/Genetic_code
Today codons consist of 3 nucleotides and therefore have 64 possibilities
These code for 20 amino_acids plus a start and stop codon .
If there was originally only one base, as suggested above, then there were at that time only 4 distinct triplets
001
010
100
111
Which could simply be flipped over to make
011
101
110
000
You only need to know the first 2 bases (and the orientation) to select the right triplet 

All of the codons that consist entirely of Cytosine and guanine only use the first two bases and completely ignore the third
http://study.com/cimages/multimages/16/Cytosine_Guanine_base_pair.png (note the similarity to 3-Aminobenzoic_acid)
These code for:
https://en.wikipedia.org/wiki/Glycine (the simplest possible amino acid)
https://en.wikipedia.org/wiki/Alanine
https://en.wikipedia.org/wiki/Arginine
https://en.wikipedia.org/wiki/Proline


Nanobes/Microtubules/Ribosomes: https://plus.google.com/100636757164161999940/posts/a9kXMxcmc7p
phosphorus is part of the backbone of RNA. Liquid crystal PAHs lack a backbone. Maybe this is why they haven't found phosphorus in nanobes

https://en.wikipedia.org/wiki/Miller–Urey_experiment

A typical tRNA has 75 bases.
2^75 = 3.77 * 10^22
1 mole of tRNA would weigh 25 kg and contain 6 * 10^23 molecules

After a primordial strand replicated itself the two strands would have a strong tendency to remain together.
It is quite possible that the first useful molecule to evolve was an unzipper like the protein helicases


https://en.wikipedia.org/wiki/Coenzyme_A
http://www.chem.ucla.edu/harding/IGOC/N/nucleotide04.jpg

https://en.wikipedia.org/wiki/Citric_acid_cycle

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  • 1 year later...

I cant believe no one responded! If you people don't think this is interesting thing what the heck do you think is interesting?

No response because this does not seem to be a serious hypothesis. All I can find about this is a stub article in Wiki and a link to a crackpot pseudo-wiki called intergalactic ballocks, or some such.

 

Provide some links to reputable sources if you want anyone to get interested. In view of your recent mad contribution on the density of the Earth and your unscientific remarks about the electronic structure of iron atoms, I remain very sceptical of anything you post unless it is corroborated by what I consider a trustworthy source. 

Edited by exchemist
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intergalactic ballocks? I have no clue what you are babbling about.

 

and why are you asking me to appeal to Authority for you? 

Because we are under no obligation to pay attention to the ravings of every nutter on the street corner - and there are plenty of those on forums like this one.

 

You, therefore, need to do a ittle basic work to show you are not such a nutter, if you want people to give your ideas the time of day. 

 

Who is putting forward this hypothesis? What critical reception has it had? Where can we read more about it, in reputable sources?  

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In other words you only believe what you are told to believe and nobody in authority has told you to believe this.

Me, I prefer to think for myself. But I guess that's not your thing. You might want to give it a try sometime

Edited by granpa
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In other words you only believe what you are told to believe and nobody in authority has told you to believe this.

Me, I prefer to think for myself. But I guess that's not your thing. You might want to give it a try sometime

Well I have a choice, don't I? A choice between you, who are telling me one thing, and established science, which seems to be telling me something different. 

 

So, as I'm sure you would do in my position, I look for reasons as to which version I should believe.

 

I am perfectly open to your version if you can show is is soundly based, by providing some references to show that people who are experts in the field, which I am not, take it seriously. 

 

But anyway, I have got what I wanted from your replies. Evidently this is some notion of your own, which has not been subjected to any scientific scrutiny. Correct? 

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Me, I prefer to think for myself.

 

Why do you mostly plagiarize from Wikipedia then?

 

You're not really saying anything about what you think nor asking any questions of others. We have a pretty good tolerance around here for alternative ideas, and if even we aren't engaging with you, you may wish to look in the mirror rather than raging about our desire for our "demand for appeal to authority."

 

 

Vampires did not avoid mirrors because they cast no reflection but because mirrors became so unflattering with the illusion of fuzzy focus wrenched away, :phones:

Buffy

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