Bob....
Okay, I'm weeks behind on the debate ! Busy time of year. Your new link is interesting, more theories, reasonable ones that don't seem to bring in insurmountable improbabilities, but still with many problems regarding restrictions in chemical combining.
The hydrothermal vent theories have already been contested. Assuming a metabolism first, only leads onto the inevitable....A self replicating system had to form at some point and the article admits that it can't work without the RNA world. RNA is always the big problem....Accumulation of the essential compounds is highly restrictive under the vent conditions described in the article, they are far too short lived e.g. RNA bases are destroyed very quickly in water at 100 ° C - adenine and guanine have half lives of about a year, uracil about 12 years, and cytosine only 19 days. In fact cytosine is unstable at temperatures as cold as 0 c....Without cytosine neither DNA or RNA can exist. Under plausible prebiotic conditions, the tendency is for biological macromolecules to break apart into the ‘building blocks’, not the other way round.
Its good to see that they recognise the incredible problems facing current established abiogenesis theories, and subsequently they have to forever turn to new ideas.
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Abiogenesis is a difficult problem, and no mistake. But you are not approaching the literature with any view to figuring it out, but only to find excuses for why the problem cannot be solved. And so you are not much interested in understanding what the literature has to say.
Difficult problem ....( Understatement of the year ! ) I've looked into this subject from various angles as a creationist, and in the past as an evolutionist, read the different sides of the literature, and tried to figure it out. My conclusions are that it is totally unrealistic. I think that you are looking at it from only one angle, the one that fits in with your belief. I am trying to be open minded on this subject.....My previous posts did say that abiogenesis is possible under guidance of an omnipotent being, because my belief is based on the scripture that 'All things are possible with God'. However, there is no reasoning by present evidence to say that random abiogenesis has occured. It is all speculation, and remains so. I can't kid myself like I used to. Equally 'all things possible with God' can mean that he has chosen to directly create. What is possible, is highlighted by God showing us what he has chosen to make us see as impossible under his own physical laws, he sets his own limits under the laws he created for us. Outside of his created physical laws all things are possible. His written word seems to point to direct creation stages as the means, and extensive anthropic design factors seem to say that this is the course that he has taken. More like a designer creator of products than a planter of seeds. We differ in that you believe that he planted the seeds and I believe that he creates and plants. We both though recognise that God is involved in someway, which is thankfully, something that we can agree on.
If the evidence of abiogenesis is not 100% forthcoming, should it be promoted as fact ?..... Books, websites, magazines, T.V. programmes play it out as if lifes origins have been solved, still using the old tales about random chemical combinations in a prebiotic soup. This should not be promulgated in this way, but put across to us as only an unfounded idea. Which it is.
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I can see that you can't even grasp the aspects about cellular amino acids and proteins, the requirements, upwards to 20 L-isomer amino acids that are needed to form a most basic protocell.
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There is, as I keep trying to explain to you, NO requirement that 20 different kinds (of amino acids) had to be used from the beginning.
I have said UPWARDS to, I agree with the hypothetical assumption that not all 20 need have been used at the beginning. A lesser amount, but not down to a miniscule amount to invalidate protein function. Proteins would have to had a certain amount of specificity. However, in reality, and evidentially 22 maximum are used in life giving proteins. Additionally, the 'left handed' amino acids are required for life. 'Right handed' amino acids exist, and only make a dead end barrier to the formation of life if they bond with the 'left handed' amino acids, as would have happened in the pre-biotic soup. This is called a lock out, polymerylization could not continue. A vast primeval sea of only the proteinous 20 L-isomer amino acids alone would have given a greater probability that a simple life form could have formed, but this scenario is pure fantasy. Amino acids form readily out of carbon, nitrogen, oxygen and hydrogen atoms as these atoms are abundant. The reality of biochemistry is that all the other hundreds of types of amino acids in D and L form would have existed in the speculative primeval sea, these would have only been a great restriction to the reacting and combining of proteinous amino acids.
We can get an idea of the number of amino acids required to make a substantial protein. Insulin has one of the smallest amounts which is 51. More importantly ancient proteins in bacteria, that apparently date near the beginning of time, the amino acid contents are 56. To put it down to 14 aa is extreme, (and not all different ones) This is a hypothetical amount, and by no means says that a protocell would work with so few, but a minute amount is theorised because it is assumed that a small amount would have been the case at the outset. Even computational models cannot create a tertiary structure with less than 23 amino acids, which is the key to protein function.
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You keep going off on a tangent to look at modern day cells and other various proteins that aren't relative at all to the earliest assumed workings of protocells, those with different and specific functions.
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What "assumptions" about the workings of protocells are you working from? No possibilities should be foreclosed at this early stage of investigation. There is no reason to assume that the protocell had any control over transport across the membrane, or any co-ordination between the membrane splitting and the nucleic-acid copying, for example.
The workings of a protocell that would function on a bare minimum, based on its descendant the cell, its workings, laws of biology etc. But this is purely hypothetical. A very basic cell would need proteins to serve the cell so that it continues to work and survive. Each protein needs to have a regulatory protein to assure that nothing go's wrong. I tried to play devils advocate by reducing the modern minimal amount of 250 proteins to 12 ...6 essentials and each essential protein needs a regulatory protein.
You wouldn't say that your watch would work below a minimum amount of parts. There is a minimal limit before it would stop functioning. It might just about function if non vital parts were taken away and only for a while before breakdown, if some more vital parts were disposed of. This is the same with the cell, or in this case an earlier hypothetical protocell. It would have had to rely on vital units to work and survive. Against all of the tremendous odds the individual proteins would have had to have formed in the pre-biotic soup and then each protein would have had to unite to form the protocell. Avoiding DNA so as to simplify, RNA would have had to form so that it would have the ability to self replicate. A watch is not a functioning unit if cannot give us the measure of time if it is only five cogs and one hand lying next to each other.
Such is life, things have to work in unison with a limited amount of parts to work and progress. We cannot go below a certain amount. A fact of life. Physical laws. Irreduceable complexity.
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I stepped this hypothetical protocell down to a ridiculously low amount of only 12 proteins .
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Why not to ZERO proteins? On what basis do you claim that the first protocells had to use proteins in any way?
On the laws of nature of cells, and in your own words you recognise the laws regarding the building blocks of proteins, amino acids.....
Your quote.....>>" *I* am made up from the 20, because I share common ancestry with the other creatures that have settled on that set of 20."<<
Common ancestry also recognises that the 20 life giving amino acids make up proteins, and proteins are the mainstay of any cell.... If you say zero proteins, then you might as well say zero amino acids.
Modern cells use proteins. The essence of life. If something else comes up where proteins are not the only working blocks of life then you could possibly say zero proteins.
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They are not "unique"; a different set could have been used. There is nothing magical about the set of 20, and no need that it has to be as large as 20, or 14 either. You explained where you got your number "14" from:
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Are you on the same planet ? Are you made up of non life giving amino acids then ?.....
Your quote:
*I* am made up from the 20, because I share common ancestry with the other creatures that have settled on that set of 20. Other life-forms could use a completely different set; we do have examples of life-forms on this planet which slightly vary the set of amino acids used, and completely unrelated life-forms would have no requirement to use a set that was particularly similar, although it would be surprising if any of the very simple amino acids like glycine or alanine were unused.
What other set of amino acids ? Left handed or right handed, or a mixture ? How could these create life ? Why did they not formulate in the pre-biotic soup ? They would have faced the same chemical barriers and combination probabilities that the known 20 life forming amino acids had to face. In the billions of years that the life forming amino acids were said to have been reacting and combining. Why did the other sets not combine to form life ? Surely these sets would have formed life, given the same time scale, vast primeval sea and conditions that were known for the 20 life giving amino acids. How would they have stopped from reacting with other amino acids ? How would other sets work with DNA, RNA, codons, bases. Is there hard evidence in what you say ? Would these other amino acids have an inbuilt genetic code ?
My quote:
Out of all of the hundreds and hundreds of amino acids (and all the other millions of molecules) only 20 'left handed' amino acid molecules have the essential ingredients that are required for life...the ingredients amongst zillions of non-life giving molecules, a miniscule amount needed to animate life, the first protocell.......And you say that they are not unique !!
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That's right, and I will keep telling you this until you hear. THERE IS NOTHING SPECIAL ABOUT THOSE TWENTY AS OPPOSED TO ANY OTHER AMINO ACIDS. It could have ended up being a different set of amino acids: some mixture of electropositive, electronegative, and neutral, surely, but not necessarily the same ones.
This is interesting, please show me in detail one other different set of amino acids that could be life forming and how they would have bonded to be producers of life and subsequently work with RNA, DNA to code the proteins etc.. At present we have 2 bases consisting of pyrimidine and purine that use 64 triplet codons for 20 amino acids, a lot of redundancy to tackle error transmission. Little is known how the bases code for the 20 essential amino acids. How on earth would they code for a different set of amino acids ? The bases work with the proteinous amino acids, so are you saying that a new set of amino acids would require a new form of bases ? How does this work out regarding the current understanding of molecular biology ?
If you can show me life where RNA, DNA etc etc work hand in hand with another set of amino acids and the other amino acids L-isomer or D-isomer ones are involved in lifeforms, then you can say that the twenty that are used now are not unique. Other than that you are wasting your breath and typing in caps fruitlessly. For now it happens to be that the evidence is that existing life in the realm that we live in proves that they are unique. Hypothetically you can say that anything can be used for life, realistically and evidentially you can't. Whatever, other fictional sets would face the same extensive probability factors and the chemical barriers required to combine.