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Enzyme-free Krebs cycle: Big new find in the extrapolation of life


From Linda Geddes at New Scientist:

Metabolism may be older than life itself and start spontaneously

However, the enzyme-free Krebs cycle that Ralser observed isn’t the complete biochemical cycle as it operates in modern cells. That may have come later, after enzymes evolved.

Furthermore, the sulphate-driven cycle has so far only been shown to run in one direction (the oxidative one). In some species, the Krebs cycle can also run in reverse and help to incorporate CO2 into the building of new carbohydrates. Some think it may therefore have been involved in early carbon fixation, in which case you’d expect to see the cycle spontaneously turning in this direction too.

Until researchers can demonstrate both these things, they cannot claim that metabolism came before cells and life, some experts think.

“This is a neat paper and the findings are striking and careful,” says Nick Lane, an evolutionary biochemist at University College London. “But this is strictly the oxidative Krebs cycle, which is certainly not ancient. It probably became oxidative after the rise of molecular oxygen in the atmosphere. More.

The obvious problem with this Krebs cycle thesis and all the others is what they don’t explain: If there is a simple way life can just come into existence, why has no one been able to demonstrate abiogenesis (spontaneous origin of life) today?

See also: What we know and don’t know about the origin of life

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"If there is a simple way life can just come into existence, why has no one been able to demonstrate abiogenesis (spontaneous origin of life) today? It gets worst; materialists have now realized that they will not be able to replicate life...for starters, they can't even define life, so how are they going to replicate something they can't define? So... I have noticed a bit of a change in their cunning lately...Since many people like me mock them for their inability to demonstrate even one piece of evidence that swayed them to believe in abiogenesis, they switched into a new tactic I think; "...If life can't be replicated by an intelligent agency that can only mean one thing and that's what materialists will settle on...", Well, I'm not sure about you News, but materialists are willing to give up all the progress in the science, the works in this field and be humiliated by it... as long as they can't, and should not acknowledge the obvious alternative... Am I overstating it? My kids often correct me and I have to show all the humility I have left to do it...it's not easy to challenge some of the best minds in the world who wish to comment here... J-Mac
“How do you bring these elements together in one environment and in non-extreme conditions, and make them work?” he asks. “This is still a big challenge.” Journal reference: Nature Ecology & Evolution: DOI: 10.1038/s41559-017-0083 Dionisio

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