A study has found that lipid membranes can be selectively permeable to
one or the other sugar or amino acid enantiomer. The study used membrane >models inspired by the membranes of modern organisms, so is not directly >relevant to abiogenesis. However it still raises the possibility that >membrane selectivity was the source of chirality in biological
molecules. One possible issue is does this effect require chiral
membrane lipids; if so it only move the question of the origin of
chirality from sugars and amino acids to lipids.
https://www.biorxiv.org/content/10.1101/2024.04.23.590732v2.full.pdf
On 8/18/2024 12:01 PM, Bob Casanova wrote:
On Sun, 18 Aug 2024 00:08:49 +0100, the following appeared
in talk.origins, posted by Ernest Major
<{$to$}@meden.demon.co.uk>:
A study has found that lipid membranes can be selectively permeable toISTM that this is similar to the "matter/antimatter"
one or the other sugar or amino acid enantiomer. The study used membrane >>> models inspired by the membranes of modern organisms, so is not directly >>> relevant to abiogenesis. However it still raises the possibility that
membrane selectivity was the source of chirality in biological
molecules. One possible issue is does this effect require chiral
membrane lipids; if so it only move the question of the origin of
chirality from sugars and amino acids to lipids.
imbalance; neither is inherently more "natural" than the
other, but one became more prevalent. And IIRC, the m/am
imbalance is now assumed to be a matter of chance in the
original ratio. I could; of course, be mistaken in that;
it's been years since I followed it even casually.
https://www.biorxiv.org/content/10.1101/2024.04.23.590732v2.full.pdf
For chirality there is an equilibrium ratio between the mirror images.
D sugars have been known to exist in solution at higher concentrations
that L forms. My guess is that L forms of amino acids are likely to
exist at higher concentrations in solution, but it doesn't matter. The >chirality of life was set by the first enzymatic reactions used by life
to get started. The use of L amino acids would have been set by the
first functional proteases that could produce peptide bonds or for the
RNA world scenario it would have been L amino acids that were probably
used to make the first nucleotides. The active sites of the first
replicated enzymes would have set the chirality, and that chirality
would have been maintained due to subsequent enzymes would have to be >compatible for the ones that came before. Only one form fits into the
active site of an enzyme that uses that amino acid or carbohydrate.
Enzymes have evolved to convert one form into the other because they >spontaneously change from D to L and if left to themselves you would get
a mix at a certain ratio in solution. I really do not understand why
anyone is worried about why life on earth uses D sugars and L amino
acids. It would have been set, probably, by the enzymes of the first
self replicators, and would have likely been maintained by selection as >everything would have worked better if new functions could use the same >materials.
I found this paper that L amino acids would have been more efficiently >incorporated into our current translation system (making proteins using >ribosomes, mRNA and tRNAs) because both D and L amino acids transition >between the 2 and 3 position of the ribose (at the end of the tRNA)
several times a second, but L forms are found more often at the 3
position that is used in the translation system. It is a reason to use
L amino acids to make proteins using our current translation system, but
L amino acids would have been selected long before by their use in
making nucleotides and other essential biochemicals for the lifeform
before the translation system existed.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC281674/
On 8/18/2024 12:01 PM, Bob Casanova wrote:Quite some time ago I came across (borrowed?) an old
On Sun, 18 Aug 2024 00:08:49 +0100, the following appeared
in talk.origins, posted by Ernest Major
For chirality there is an equilibrium ratio between the mirror images. D sugars have been known to exist in solution at higher concentrations
that L forms. My guess is that L forms of amino acids are likely to
exist at higher concentrations in solution, but it doesn't matter. The chirality of life was set by the first enzymatic reactions used by life
to get started. The use of L amino acids would have been set by the
first functional proteases that could produce peptide bonds or for the
RNA world scenario it would have been L amino acids that were probably
used to make the first nucleotides. The active sites of the first replicated enzymes would have set the chirality, and that chirality
would have been maintained due to subsequent enzymes would have to be compatible for the ones that came before. Only one form fits into the active site of an enzyme that uses that amino acid or carbohydrate.
Enzymes have evolved to convert one form into the other because they spontaneously change from D to L and if left to themselves you would get
a mix at a certain ratio in solution.
RonO wrote:
On 8/18/2024 12:01 PM, Bob Casanova wrote:Quite some time ago I came across (borrowed?) an old
On Sun, 18 Aug 2024 00:08:49 +0100, the following appeared
in talk.origins, posted by Ernest Major
For chirality there is an equilibrium ratio between the mirror images. D
sugars have been known to exist in solution at higher concentrations
that L forms. My guess is that L forms of amino acids are likely to
exist at higher concentrations in solution, but it doesn't matter. The
chirality of life was set by the first enzymatic reactions used by life
to get started. The use of L amino acids would have been set by the
first functional proteases that could produce peptide bonds or for the
RNA world scenario it would have been L amino acids that were probably
used to make the first nucleotides. The active sites of the first
replicated enzymes would have set the chirality, and that chirality
would have been maintained due to subsequent enzymes would have to be
compatible for the ones that came before. Only one form fits into the
active site of an enzyme that uses that amino acid or carbohydrate.
Enzymes have evolved to convert one form into the other because they
spontaneously change from D to L and if left to themselves you would get
a mix at a certain ratio in solution.
scifi Star Trek novel called "Spock Must Die". There's
even a wiki page for it
https://en.wikipedia.org/wiki/Spock_Must_Die!
Anyways, that bad ol transporter makes a second
Spock. This second Spock was the chiral opposite
of the original Spock and was basically starving
because the food had the wrong chirality. Cool
stuff for 1970. Moral of the story is that the
chirality preference is universal!
RonO wrote:
On 8/18/2024 12:01 PM, Bob Casanova wrote:Quite some time ago I came across (borrowed?) an old
On Sun, 18 Aug 2024 00:08:49 +0100, the following appeared
in talk.origins, posted by Ernest Major
For chirality there is an equilibrium ratio between the mirror images.
D sugars have been known to exist in solution at higher concentrations
that L forms. My guess is that L forms of amino acids are likely to
exist at higher concentrations in solution, but it doesn't matter.
The chirality of life was set by the first enzymatic reactions used by
life to get started. The use of L amino acids would have been set by
the first functional proteases that could produce peptide bonds or for
the RNA world scenario it would have been L amino acids that were
probably used to make the first nucleotides. The active sites of the
first replicated enzymes would have set the chirality, and that
chirality would have been maintained due to subsequent enzymes would
have to be compatible for the ones that came before. Only one form
fits into the active site of an enzyme that uses that amino acid or
carbohydrate. Enzymes have evolved to convert one form into the other
because they spontaneously change from D to L and if left to
themselves you would get a mix at a certain ratio in solution.
scifi Star Trek novel called "Spock Must Die". There's
even a wiki page for it
https://en.wikipedia.org/wiki/Spock_Must_Die!
Anyways, that bad ol transporter makes a second
Spock. This second Spock was the chiral opposite
of the original Spock and was basically starving
because the food had the wrong chirality. Cool
stuff for 1970. Moral of the story is that the
chirality preference is universal!
On 8/18/2024 12:01 PM, Bob Casanova wrote:
On Sun, 18 Aug 2024 00:08:49 +0100, the following appeared
in talk.origins, posted by Ernest Major
<{$to$}@meden.demon.co.uk>:
A study has found that lipid membranes can be selectively permeable toISTM that this is similar to the "matter/antimatter"
one or the other sugar or amino acid enantiomer. The study used membrane >>> models inspired by the membranes of modern organisms, so is not directly >>> relevant to abiogenesis. However it still raises the possibility that
membrane selectivity was the source of chirality in biological
molecules. One possible issue is does this effect require chiral
membrane lipids; if so it only move the question of the origin of
chirality from sugars and amino acids to lipids.
imbalance; neither is inherently more "natural" than the
other, but one became more prevalent. And IIRC, the m/am
imbalance is now assumed to be a matter of chance in the
original ratio. I could; of course, be mistaken in that;
it's been years since I followed it even casually.
https://www.biorxiv.org/content/10.1101/2024.04.23.590732v2.full.pdf
For chirality there is an equilibrium ratio between the mirror images.
D sugars have been known to exist in solution at higher concentrations
that L forms. My guess is that L forms of amino acids are likely to
exist at higher concentrations in solution, but it doesn't matter. The chirality of life was set by the first enzymatic reactions used by life
to get started. The use of L amino acids would have been set by the
first functional proteases that could produce peptide bonds or for the
RNA world scenario it would have been L amino acids that were probably
used to make the first nucleotides. The active sites of the first
replicated enzymes would have set the chirality, and that chirality
would have been maintained due to subsequent enzymes would have to be compatible for the ones that came before. Only one form fits into the
active site of an enzyme that uses that amino acid or carbohydrate.
Enzymes have evolved to convert one form into the other because they spontaneously change from D to L and if left to themselves you would
get a mix at a certain ratio in solution. I really do not understand
why anyone is worried about why life on earth uses D sugars and L amino acids.
It would have been set, probably, by the enzymes of the first self replicators, and would have likely been maintained by selection as
everything would have worked better if new functions could use the same materials.
I found this paper that L amino acids would have been more efficiently incorporated into our current translation system (making proteins using ribosomes, mRNA and tRNAs) because both D and L amino acids transition between the 2 and 3 position of the ribose (at the end of the tRNA)
several times a second, but L forms are found more often at the 3
position that is used in the translation system. It is a reason to use
L amino acids to make proteins using our current translation system,
but L amino acids would have been selected long before by their use in
making nucleotides and other essential biochemicals for the lifeform
before the translation system existed.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC281674/
Ron Okimoto
On 19/08/2024 04:11, Pro Plyd wrote:
RonO wrote:
On 8/18/2024 12:01 PM, Bob Casanova wrote:Quite some time ago I came across (borrowed?) an old
On Sun, 18 Aug 2024 00:08:49 +0100, the following appeared
in talk.origins, posted by Ernest Major
For chirality there is an equilibrium ratio between the mirror images.
D sugars have been known to exist in solution at higher concentrations
that L forms. My guess is that L forms of amino acids are likely to
exist at higher concentrations in solution, but it doesn't matter. The
chirality of life was set by the first enzymatic reactions used by life
to get started. The use of L amino acids would have been set by the
first functional proteases that could produce peptide bonds or for the
RNA world scenario it would have been L amino acids that were probably
used to make the first nucleotides. The active sites of the first
replicated enzymes would have set the chirality, and that chirality
would have been maintained due to subsequent enzymes would have to be
compatible for the ones that came before. Only one form fits into the
active site of an enzyme that uses that amino acid or carbohydrate.
Enzymes have evolved to convert one form into the other because they
spontaneously change from D to L and if left to themselves you would
get a mix at a certain ratio in solution.
scifi Star Trek novel called "Spock Must Die". There's
even a wiki page for it
https://en.wikipedia.org/wiki/Spock_Must_Die!
Anyways, that bad ol transporter makes a second
Spock. This second Spock was the chiral opposite
of the original Spock and was basically starving
because the food had the wrong chirality. Cool
stuff for 1970. Moral of the story is that the
chirality preference is universal!
That is probably based on Arthur C. Clarke's 1950 short story
"Technical Error" (originally published as "The Reversed Man"). (There
is also, judging by descriptions, a more tongue in cheek 1987 story by
Isaac Asimov - "Left to Right".)
https://en.wikipedia.org/wiki/Technical_Error
On 8/19/2024 4:07 AM, Athel Cornish-Bowden wrote:
On 2024-08-18 18:37:19 +0000, RonO said:
On 8/18/2024 12:01 PM, Bob Casanova wrote:
On Sun, 18 Aug 2024 00:08:49 +0100, the following appeared
in talk.origins, posted by Ernest Major
<{$to$}@meden.demon.co.uk>:
A study has found that lipid membranes can be selectively permeable to >>>>> one or the other sugar or amino acid enantiomer. The study used membrane >>>>> models inspired by the membranes of modern organisms, so is not directly >>>>> relevant to abiogenesis. However it still raises the possibility that >>>>> membrane selectivity was the source of chirality in biologicalISTM that this is similar to the "matter/antimatter"
molecules. One possible issue is does this effect require chiral
membrane lipids; if so it only move the question of the origin of
chirality from sugars and amino acids to lipids.
imbalance; neither is inherently more "natural" than the
other, but one became more prevalent. And IIRC, the m/am
imbalance is now assumed to be a matter of chance in the
original ratio. I could; of course, be mistaken in that;
it's been years since I followed it even casually.
https://www.biorxiv.org/content/10.1101/2024.04.23.590732v2.full.pdf >>>>>
For chirality there is an equilibrium ratio between the mirror images.
D sugars have been known to exist in solution at higher concentrations
that L forms. My guess is that L forms of amino acids are likely to
exist at higher concentrations in solution, but it doesn't matter. The
chirality of life was set by the first enzymatic reactions used by life
to get started. The use of L amino acids would have been set by the
first functional proteases that could produce peptide bonds or for the
RNA world scenario it would have been L amino acids that were probably
used to make the first nucleotides. The active sites of the first
replicated enzymes would have set the chirality, and that chirality
would have been maintained due to subsequent enzymes would have to be
compatible for the ones that came before. Only one form fits into the
active site of an enzyme that uses that amino acid or carbohydrate.
Enzymes have evolved to convert one form into the other because they
spontaneously change from D to L and if left to themselves you would
get a mix at a certain ratio in solution. I really do not understand
why anyone is worried about why life on earth uses D sugars and L amino
acids.
Me neither. It had to be one or the other, and with appropriate enzymes
D aminoacids would have been just as good, but having made the choice
life had to stick with it.
An interesting case is that of lactate. Both D-lactate and L-lactate
are important metabolites, and the lactate dehydrogenases that act on
them are quite different from one another.
As I indicated these carbon molecules transition between forms in
solution. For some important amino acids cells have enzymes that
convert D amino acids to the L form. For lactate it probably became important to deal with the terminal product of glycolysis, so instead
of evolving a system to keep changing one to the other, enzymes evolved
to deal with both D and L forms so that the amount of lactate could be regulated more efficiently.
It would have been set, probably, by the enzymes of the first self
replicators, and would have likely been maintained by selection as
everything would have worked better if new functions could use the same
materials.
I found this paper that L amino acids would have been more efficiently
incorporated into our current translation system (making proteins using
ribosomes, mRNA and tRNAs) because both D and L amino acids transition
between the 2 and 3 position of the ribose (at the end of the tRNA)
several times a second, but L forms are found more often at the 3
position that is used in the translation system. It is a reason to use
L amino acids to make proteins using our current translation system,
but L amino acids would have been selected long before by their use in
making nucleotides and other essential biochemicals for the lifeform
before the translation system existed.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC281674/
Ron Okimoto
On Sun, 18 Aug 2024 00:08:49 +0100, the following appeared
in talk.origins, posted by Ernest Major
<{$to$}@meden.demon.co.uk>:
A study has found that lipid membranes can be selectively permeable to
one or the other sugar or amino acid enantiomer. The study used membrane >models inspired by the membranes of modern organisms, so is not directly >relevant to abiogenesis. However it still raises the possibility that >membrane selectivity was the source of chirality in biological
molecules. One possible issue is does this effect require chiral
membrane lipids; if so it only move the question of the origin of
chirality from sugars and amino acids to lipids.
ISTM that this is similar to the "matter/antimatter"
imbalance; neither is inherently more "natural" than the
other, but one became more prevalent. And IIRC, the m/am
imbalance is now assumed to be a matter of chance in the
original ratio. I could; of course, be mistaken in that;
it's been years since I followed it even casually.
https://www.biorxiv.org/content/10.1101/2024.04.23.590732v2.full.pdf
Bob Casanova <nospam@buzz.off> wrote:
On Sun, 18 Aug 2024 00:08:49 +0100, the following appeared
in talk.origins, posted by Ernest Major
<{$to$}@meden.demon.co.uk>:
A study has found that lipid membranes can be selectively permeable toISTM that this is similar to the "matter/antimatter"
one or the other sugar or amino acid enantiomer. The study used membrane
models inspired by the membranes of modern organisms, so is not directly
relevant to abiogenesis. However it still raises the possibility that
membrane selectivity was the source of chirality in biological
molecules. One possible issue is does this effect require chiral
membrane lipids; if so it only move the question of the origin of
chirality from sugars and amino acids to lipids.
imbalance; neither is inherently more "natural" than the
other, but one became more prevalent. And IIRC, the m/am
imbalance is now assumed to be a matter of chance in the
original ratio. I could; of course, be mistaken in that;
it's been years since I followed it even casually.
https://www.biorxiv.org/content/10.1101/2024.04.23.590732v2.full.pdf
It isn't. The left-handed molecules can be converted into right-handed
ones, and vica versa, by taking them apart and reassembling them.
For matter/antimatter there is no such possibility.
Disassembling doesn't help,
because you cannot turn antiquarks into quarks.
Biological chirality is a triviality,
the matter/antimatter imbalance is a deep problem.
Where has all that antimatter gone?
Bob Casanova <nospam@buzz.off> wrote:
On Sun, 18 Aug 2024 00:08:49 +0100, the following appeared
in talk.origins, posted by Ernest Major
<{$to$}@meden.demon.co.uk>:
A study has found that lipid membranes can be selectively permeable toISTM that this is similar to the "matter/antimatter"
one or the other sugar or amino acid enantiomer. The study used membrane >>> models inspired by the membranes of modern organisms, so is not directly >>> relevant to abiogenesis. However it still raises the possibility that
membrane selectivity was the source of chirality in biological
molecules. One possible issue is does this effect require chiral
membrane lipids; if so it only move the question of the origin of
chirality from sugars and amino acids to lipids.
imbalance; neither is inherently more "natural" than the
other, but one became more prevalent. And IIRC, the m/am
imbalance is now assumed to be a matter of chance in the
original ratio. I could; of course, be mistaken in that;
it's been years since I followed it even casually.
https://www.biorxiv.org/content/10.1101/2024.04.23.590732v2.full.pdf
It isn't. The left-handed molecules can be converted into right-handed
ones, and vica versa, by taking them apart and reassembling them.
For matter/antimatter there is no such possibility.
Disassembling doesn't help,
because you cannot turn antiquarks into quarks.
Biological chirality is a triviality,
the matter/antimatter imbalance is a deep problem.
Where has all that antimatter gone?
On Sun, 18 Aug 2024 21:11:53 -0600, the following appeared
in talk.origins, posted by Pro Plyd
<invalide@invalid.invalid>:
RonO wrote:
On 8/18/2024 12:01 PM, Bob Casanova wrote:
On Sun, 18 Aug 2024 00:08:49 +0100, the following appeared
in talk.origins, posted by Ernest Major
stuff for 1970. Moral of the story is that theCheck out the Roger Zelazny novel, "Doorways in the Sand".
chirality preference is universal!
J. J. Lodder wrote:
Bob Casanova <nospam@buzz.off> wrote:
On Sun, 18 Aug 2024 00:08:49 +0100, the following appeared
in talk.origins, posted by Ernest Major
<{$to$}@meden.demon.co.uk>:
A study has found that lipid membranes can be selectively permeable to >>>> one or the other sugar or amino acid enantiomer. The study usedISTM that this is similar to the "matter/antimatter"
membrane
models inspired by the membranes of modern organisms, so is not
directly
relevant to abiogenesis. However it still raises the possibility that
membrane selectivity was the source of chirality in biological
molecules. One possible issue is does this effect require chiral
membrane lipids; if so it only move the question of the origin of
chirality from sugars and amino acids to lipids.
imbalance; neither is inherently more "natural" than the
other, but one became more prevalent. And IIRC, the m/am
imbalance is now assumed to be a matter of chance in the
original ratio. I could; of course, be mistaken in that;
it's been years since I followed it even casually.
https://www.biorxiv.org/content/10.1101/2024.04.23.590732v2.full.pdf
It isn't. The left-handed molecules can be converted into right-handed
ones, and vica versa, by taking them apart and reassembling them.
For matter/antimatter there is no such possibility.
Disassembling doesn't help,
because you cannot turn antiquarks into quarks.
Biological chirality is a triviality,
the matter/antimatter imbalance is a deep problem.
Where has all that antimatter gone?
Well, sorta agree with the analogy if one only
is considering the ratio. But also agree with the
observation about matter/anti-matter not being
able to be turned into their opposites. Just
happened to come across the following, another
mystery of sorts...
https://www.livescience.com/physics-mathematics/particle-physics/a-remarkable-conspiracy-why-is-matter-neutral-physicist-frank-close-explores-the-mystery-in-a-new-book
July 28, 2024
Since the discovery of the proton and the
electron in the 20th century, a mystery
persists at the core of the atom: Despite
belonging to completely different particle
families and being radically different in
size, the charges of these two particles
completely balance each other out — enabling
a universe where gravity dominates. But why?
...
On 24/08/2024 05:34, Pro Plyd wrote:
J. J. Lodder wrote:
Bob Casanova <nospam@buzz.off> wrote:
On Sun, 18 Aug 2024 00:08:49 +0100, the following appeared
in talk.origins, posted by Ernest Major
<{$to$}@meden.demon.co.uk>:
A study has found that lipid membranes can be selectively permeable to >>>>> one or the other sugar or amino acid enantiomer. The study usedISTM that this is similar to the "matter/antimatter"
membrane
models inspired by the membranes of modern organisms, so is not
directly
relevant to abiogenesis. However it still raises the possibility that >>>>> membrane selectivity was the source of chirality in biological
molecules. One possible issue is does this effect require chiral
membrane lipids; if so it only move the question of the origin of
chirality from sugars and amino acids to lipids.
imbalance; neither is inherently more "natural" than the
other, but one became more prevalent. And IIRC, the m/am
imbalance is now assumed to be a matter of chance in the
original ratio. I could; of course, be mistaken in that;
it's been years since I followed it even casually.
https://www.biorxiv.org/content/10.1101/2024.04.23.590732v2.full.pdf
It isn't. The left-handed molecules can be converted into right-handed
ones, and vica versa, by taking them apart and reassembling them.
For matter/antimatter there is no such possibility.
Disassembling doesn't help,
because you cannot turn antiquarks into quarks.
Biological chirality is a triviality,
the matter/antimatter imbalance is a deep problem.
Where has all that antimatter gone?
Well, sorta agree with the analogy if one only
is considering the ratio. But also agree with the
observation about matter/anti-matter not being
able to be turned into their opposites. Just
happened to come across the following, another
mystery of sorts...
https://www.livescience.com/physics-mathematics/particle-physics/a-remarkable-conspiracy-why-is-matter-neutral-physicist-frank-close-explores-the-mystery-in-a-new-book
July 28, 2024
Since the discovery of the proton and the
electron in the 20th century, a mystery
persists at the core of the atom: Despite
belonging to completely different particle
families and being radically different in
size, the charges of these two particles
completely balance each other out — enabling
a universe where gravity dominates. But why?
...
Charge conservation is a consequence of "the global gauge invariance of
the electromagnetic field". From the existence of beta decay it can be >deduced that the charges on the proton and positron are the same (unless >you're willing to postulate that neutrinos are charged). From the
existence of electron-positron annihilation it can be deduced that the >charges on the electron and positron are equal in magnitude (unless
you're willing to postulate that photons are charged). From this we can >conclude that the charges on protons and electrons balance each other out.
So we are left to rephrase the question as "why are there equal numbers
of protons and electrons?" (Other charged particles decay to protons and >electrons (and photons and neutrinos) reasonably quickly.
On Sat, 24 Aug 2024 10:34:20 +0100, the following appeared
in talk.origins, posted by Ernest Major
<{$to$}@meden.demon.co.uk>:
On 24/08/2024 05:34, Pro Plyd wrote:This sounds to me like a close relative of the Anthropic
J. J. Lodder wrote:
Bob Casanova <nospam@buzz.off> wrote:
On Sun, 18 Aug 2024 00:08:49 +0100, the following appearedIt isn't. The left-handed molecules can be converted into right-handed >>>> ones, and vica versa, by taking them apart and reassembling them.
in talk.origins, posted by Ernest Major
<{$to$}@meden.demon.co.uk>:
A study has found that lipid membranes can be selectively permeable to >>>>>> one or the other sugar or amino acid enantiomer. The study usedISTM that this is similar to the "matter/antimatter"
membrane
models inspired by the membranes of modern organisms, so is not
directly
relevant to abiogenesis. However it still raises the possibility that >>>>>> membrane selectivity was the source of chirality in biological
molecules. One possible issue is does this effect require chiral
membrane lipids; if so it only move the question of the origin of
chirality from sugars and amino acids to lipids.
imbalance; neither is inherently more "natural" than the
other, but one became more prevalent. And IIRC, the m/am
imbalance is now assumed to be a matter of chance in the
original ratio. I could; of course, be mistaken in that;
it's been years since I followed it even casually.
https://www.biorxiv.org/content/10.1101/2024.04.23.590732v2.full.pdf >>>>
For matter/antimatter there is no such possibility.
Disassembling doesn't help,
because you cannot turn antiquarks into quarks.
Biological chirality is a triviality,
the matter/antimatter imbalance is a deep problem.
Where has all that antimatter gone?
Well, sorta agree with the analogy if one only
is considering the ratio. But also agree with the
observation about matter/anti-matter not being
able to be turned into their opposites. Just
happened to come across the following, another
mystery of sorts...
https://www.livescience.com/physics-mathematics/particle-physics/a-remarkable-conspiracy-why-is-matter-neutral-physicist-frank-close-explores-the-mystery-in-a-new-book
July 28, 2024
Since the discovery of the proton and the
electron in the 20th century, a mystery
persists at the core of the atom: Despite
belonging to completely different particle
families and being radically different in
size, the charges of these two particles
completely balance each other out — enabling
a universe where gravity dominates. But why?
...
Charge conservation is a consequence of "the global gauge invariance of
the electromagnetic field". From the existence of beta decay it can be
deduced that the charges on the proton and positron are the same (unless
you're willing to postulate that neutrinos are charged). From the
existence of electron-positron annihilation it can be deduced that the
charges on the electron and positron are equal in magnitude (unless
you're willing to postulate that photons are charged). From this we can
conclude that the charges on protons and electrons balance each other out. >>
So we are left to rephrase the question as "why are there equal numbers
of protons and electrons?" (Other charged particles decay to protons and
electrons (and photons and neutrinos) reasonably quickly.
Principle, in that a universe in which charge, rather than
gravity, dominates would most likely be one in which life
couldn't exist. IOW, "I am, therefore charges balance."
On 24/08/2024 18:08, Bob Casanova wrote:
On Sat, 24 Aug 2024 10:34:20 +0100, the following appeared
in talk.origins, posted by Ernest Major
<{$to$}@meden.demon.co.uk>:
On 24/08/2024 05:34, Pro Plyd wrote:This sounds to me like a close relative of the Anthropic
J. J. Lodder wrote:
Bob Casanova <nospam@buzz.off> wrote:
On Sun, 18 Aug 2024 00:08:49 +0100, the following appearedIt isn't. The left-handed molecules can be converted into right-handed >>>>> ones, and vica versa, by taking them apart and reassembling them.
in talk.origins, posted by Ernest Major
<{$to$}@meden.demon.co.uk>:
A study has found that lipid membranes can be selectively permeable to >>>>>>> one or the other sugar or amino acid enantiomer. The study usedISTM that this is similar to the "matter/antimatter"
membrane
models inspired by the membranes of modern organisms, so is not
directly
relevant to abiogenesis. However it still raises the possibility that >>>>>>> membrane selectivity was the source of chirality in biological
molecules. One possible issue is does this effect require chiral >>>>>>> membrane lipids; if so it only move the question of the origin of >>>>>>> chirality from sugars and amino acids to lipids.
imbalance; neither is inherently more "natural" than the
other, but one became more prevalent. And IIRC, the m/am
imbalance is now assumed to be a matter of chance in the
original ratio. I could; of course, be mistaken in that;
it's been years since I followed it even casually.
https://www.biorxiv.org/content/10.1101/2024.04.23.590732v2.full.pdf >>>>>
For matter/antimatter there is no such possibility.
Disassembling doesn't help,
because you cannot turn antiquarks into quarks.
Biological chirality is a triviality,
the matter/antimatter imbalance is a deep problem.
Where has all that antimatter gone?
Well, sorta agree with the analogy if one only
is considering the ratio. But also agree with the
observation about matter/anti-matter not being
able to be turned into their opposites. Just
happened to come across the following, another
mystery of sorts...
https://www.livescience.com/physics-mathematics/particle-physics/a-remarkable-conspiracy-why-is-matter-neutral-physicist-frank-close-explores-the-mystery-in-a-new-book
July 28, 2024
Since the discovery of the proton and the
electron in the 20th century, a mystery
persists at the core of the atom: Despite
belonging to completely different particle
families and being radically different in
size, the charges of these two particles
completely balance each other out — enabling
a universe where gravity dominates. But why?
...
Charge conservation is a consequence of "the global gauge invariance of
the electromagnetic field". From the existence of beta decay it can be
deduced that the charges on the proton and positron are the same (unless >>> you're willing to postulate that neutrinos are charged). From the
existence of electron-positron annihilation it can be deduced that the
charges on the electron and positron are equal in magnitude (unless
you're willing to postulate that photons are charged). From this we can
conclude that the charges on protons and electrons balance each other out. >>>
So we are left to rephrase the question as "why are there equal numbers
of protons and electrons?" (Other charged particles decay to protons and >>> electrons (and photons and neutrinos) reasonably quickly.
Principle, in that a universe in which charge, rather than
gravity, dominates would most likely be one in which life
couldn't exist. IOW, "I am, therefore charges balance."
In principle one could apply the Weak Anthropic Principle to place an
upper bound on any charge imbalance. (This is not necessarily a tighter
bound that can be obtained by more direct observations.)
J. J. Lodder wrote:conspiracy-why-is-matter-neutral-physicist-frank-close-explores-the-mystery-in-a-new-book
Bob Casanova <nospam@buzz.off> wrote:
On Sun, 18 Aug 2024 00:08:49 +0100, the following appeared
in talk.origins, posted by Ernest Major
<{$to$}@meden.demon.co.uk>:
A study has found that lipid membranes can be selectively permeable to >>> one or the other sugar or amino acid enantiomer. The study used membrane >>> models inspired by the membranes of modern organisms, so is not directly >>> relevant to abiogenesis. However it still raises the possibility thatISTM that this is similar to the "matter/antimatter"
membrane selectivity was the source of chirality in biological
molecules. One possible issue is does this effect require chiral
membrane lipids; if so it only move the question of the origin of
chirality from sugars and amino acids to lipids.
imbalance; neither is inherently more "natural" than the
other, but one became more prevalent. And IIRC, the m/am
imbalance is now assumed to be a matter of chance in the
original ratio. I could; of course, be mistaken in that;
it's been years since I followed it even casually.
https://www.biorxiv.org/content/10.1101/2024.04.23.590732v2.full.pdf
It isn't. The left-handed molecules can be converted into right-handed ones, and vica versa, by taking them apart and reassembling them.
For matter/antimatter there is no such possibility.
Disassembling doesn't help,
because you cannot turn antiquarks into quarks.
Biological chirality is a triviality,
the matter/antimatter imbalance is a deep problem.
Where has all that antimatter gone?
Well, sorta agree with the analogy if one only
is considering the ratio. But also agree with the
observation about matter/anti-matter not being
able to be turned into their opposites. Just
happened to come across the following, another
mystery of sorts...
https://www.livescience.com/physics-mathematics/particle-physics/a-remarkable-
July 28, 2024
Since the discovery of the proton and the
electron in the 20th century, a mystery
persists at the core of the atom: Despite
belonging to completely different particle
families and being radically different in
size, the charges of these two particles
completely balance each other out — enabling
a universe where gravity dominates. But why?
...
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