Author Topic: Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)  (Read 4276 times)

Recusant

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Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
« Reply #15 on: September 14, 2018, 08:50:05 PM »
The sword ("it's just a theory!") and shield ("were you there?") of Creationism will stand those who wield them in good stead when it comes to dealing with this. It's merely a computer model, and all that's being claimed is that a particular peptide may have been part of the formation of life on Earth. No matter--knowledge continues to advance.

"Scientists identify protein that may have existed when life began" | ScienceDaily

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How did life arise on Earth? Rutgers researchers have found among the first and perhaps only hard evidence that simple protein catalysts -- essential for cells, the building blocks of life, to function -- may have existed when life began.

Their study of a primordial peptide, or short protein, is published in the Journal of the American Chemical Society.

In the late 1980s and early 1990s, the chemist Günter Wächtershäuser postulated that life began on iron- and sulfur-containing rocks in the ocean. Wächtershäuser and others predicted that short peptides would have bound metals and served as catalysts of life-producing chemistry, according to study co-author Vikas Nanda, an associate professor at Rutgers' Robert Wood Johnson Medical School.

Human DNA consists of genes that code for proteins that are a few hundred to a few thousand amino acids long. These complex proteins -- needed to make all living-things function properly -- are the result of billions of years of evolution. When life began, proteins were likely much simpler, perhaps just 10 to 20 amino acids long. With computer modeling, Rutgers scientists have been exploring what early peptides may have looked like and their possible chemical functions, according to Nanda.

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Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
« Reply #16 on: October 21, 2018, 05:50:54 PM »
"But you weren't there!"

"Chemists find a recipe that may have jump-started life on Earth" | Science

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In the molecular dance that gave birth to life on Earth, RNA appears to be a central player. But the origins of the molecule, which can store genetic information as DNA does and speed chemical reactions as proteins do, remain a mystery. Now, a team of researchers has shown for the first time that a set of simple starting materials, which were likely present on early Earth, can produce all four of RNA’s chemical building blocks.

Those building blocks—cytosine, uracil, adenine, and guanine—have previously been re-created in the lab from other starting materials. In 2009, chemists led by John Sutherland at the University of Cambridge in the United Kingdom devised a set of five compounds likely present on early Earth that could give rise to cytosine and uracil, collectively known as pyrimidines. Then, 2 years ago, researchers led by Thomas Carell, a chemist at Ludwig Maximilian University in Munich, Germany, reported that his team had an equally easy way to form adenine and guanine, the building blocks known as purines. But the two sets of chemical reactions were different. No one knew how the conditions for making both pairs of building blocks could have occurred in the same place at the same time.

Now, Carell says he may have the answer. On Tuesday, at the Origins of Life Workshop here, he reported that he and his colleagues have come up with a simple set of reactions that could have given rise to all four RNA bases.

[Continues . . .]
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Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
« Reply #17 on: October 21, 2018, 06:37:20 PM »
Interesting as usual.
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Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
« Reply #18 on: February 12, 2019, 09:12:14 PM »
Further research on the possible routes by which life first formed.

"Membraneless protocells could provide clues to formation of early life" | ScienceDaily

Quote
Membraneless assemblies of positively- and negatively-charged molecules can bring together RNA molecules in dense liquid droplets, allowing the RNAs to participate in fundamental chemical reactions. These assemblies, called "complex coacervates," also enhance the ability of some RNA molecules themselves to act as enzymes -- molecules that drive chemical reactions. They do this by concentrating the RNA enzymes, their substrates, and other molecules required for the reaction. The results of testing and observation of these coacervates provide clues to reconstructing some of the early steps required for the origin of life on Earth in what is referred to as the prebiotic "RNA world." A paper describing the research, by scientists at Penn State, appears January 30, 2019 in the journal Nature Communications.

"We're interested in how you go from a world with no life to one with life," said Philip C. Bevilacqua, Distinguished Professor of Chemistry and of Biochemistry and Molecular Biology at Penn State and one of the senior authors of the paper. "One can imagine a lot of steps in this process, but we are not looking at the most elemental steps. We are interested in a slightly later step, to see how RNA molecules could form from their basic building blocks and if those RNA molecules could drive the reactions needed for life in the absence of proteins."

[. . .]

"It was previously known that RNA molecules can assemble and elongate in solutions with high concentrations of magnesium," said Poudyal. "Our work shows that coacervates made from certain materials allow this non-enzymatic template-mediated RNA assembly to occur even in the absence of magnesium."

The coacervates are composed of positively charged molecules called polyamines and negatively charged polymers which cluster together to form membraneless compartments in a solution. Negatively charged RNA molecules are also attracted to the polyamines in the coacervates. Within the coacervates the RNA molecules are as much as 4000 times more concentrated than in the surrounding solution. By concentrating the RNA molecules in the coacervates, RNA enzymes are more likely to find their targets to drive chemical reactions.

[Continues. . .]

The full paper is available for free: "Template-directed RNA polymerization and enhanced ribozyme catalysis inside membraneless compartments formed by coacervates" | Nature Communications
"Religion is fundamentally opposed to everything I hold in veneration — courage, clear thinking, honesty, fairness, and above all, love of the truth."
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Re: How Life May Have First Emerged On Earth (Abiogenesis Thread)
« Reply #19 on: February 13, 2019, 07:31:32 PM »
That must have been an amazingly exciting moment.
Hell is empty and all the devils are here. Wm Shakespeare