Where did Glucose come from in a prebiotic world ?
Glucose is a ubiquitous fuel in biology. It is used as an energy source in most organisms, from bacteria to humans, through either aerobic respiration, anaerobic respiration, or fermentation. Sugar phosphates are however constituents of many molecules, such as RNA, DNA, ATP and lipids, which are inevitably connected with the emergence of life. It is the fundamental role of sugar phosphates, and the virtual universality of their few metabolic interconversion sequences, that places their origin to the very early stages in the history of life. Glucose is used by Glycolysis, which is the most universal pathway in all energy metabolism, occurring in almost every living cell. The glycolytic pathway is multifunctional. Thus it provides the cell with energy (ATP)] from glucose catabolism - the process that breaks down molecules into smaller units. Glucose is the human body’s key source of energy. Through glycolysis and later in the reactions of the citric acid cycle and oxidative phosphorylation, glucose is oxidized to eventually form CO2 and water, yielding energy mostly in the form of ATP.
The ultimate origin of Glucose - sugars is a huge problem for those who believe in life from non-life without requiring a creator. In order to provide credible explanations of how life emerged, a crucial question must be answered : Where did Glucose come from in a prebiotic earth ?
The source of glucose and other sugars used in metabolic processes would have to lie in an energy-collecting process. Without some means to create such sugar, limitations of food supply for metabolic processes would make the origin of life probably impossible.
Following are the possible explanations:
Gluconeogenesis is a reverse process to glycolysis, which produces Glucose.
Nonenzymatic reactions that would be precursor mechanisms to glyconeogenesis, leading to the biosynthesis of glucose
Metabolic networks are largely composed of intermediate substrates that are not characterized by long"time stability, at least when considering geological environments and timescales. In addition, large sugar phosphates are not frequently generated in experiments that address scenarios of primordial carbon fixation.
A paper reports that Fe(II) was broadly available before oxygenation of the early Earth, implying a scenario for the first glycolytic enzymes being simple iron-binding RNA or oligopeptide molecules, which would have possessed the potential of enhancing many reactions now found in central metabolism.
Did you read that carefully ? This is a ridiculous pseudoscientific festival of just so made up fairy tale stories based on wishful thinking. We shall believe that unspecified metal catalysts where somehow ( HOW ??!! ) transformed miraculously and bridged a hudge gap from unspecified chemical reactions into the highly complex specific enzymes, highly regulated by other complex mechanisms, required in these pathways. If such baseless assertions would have been made in ANY other discipline of science, the authors would have been ridiculed. Not so in biochemistry, where any fantastic story is PLAUSIBLE, and is swallowed as serious science.
A paper from Nature magazines reported that Carbonaceous meteorites were a source of sugar-related organic compounds for the early Earth. They claimed :
Sugars, sugar alcohols and sugar acids are vital to all known lifeforms - they are components of nucleic acids (RNA, DNA), cell membranes and also act as energy sources. But there has hitherto been no conclusive evidence for the existence of polyols in meteorites, leaving a gap in our understanding of the origins of biologically important organic compounds on Earth.
Analyses of water extracts indicate that extraterrestrial processes including photolysis and formaldehyde chemistry could account for the observed compounds. We conclude from this that polyols were present on the early Earth and therefore at least available for incorporation into the ®rst forms of life.
Just because something COULD HAVE happened on the early earth, they conclude IT DID happen. The logical fallacy is evident.
Natural processes tend to produce gunk with little relevance to life.
The amounts of these chemicals were tiny—far too low to contribute to biological processes.
Chemical reactions would have somehow to select the useful compounds amongst contaminated gunk.
Sugars are very unstable, and easily decompose or react with other chemicals.
Living things require homochiral sugars, i.e. with the same ‘handedness’, but these ones would not have been.
There is no plausible method of making the sugar ribose join to some of the essential building blocks needed to make DNA or RNA, let alone into RNA or DNA themselves
Even DNA or RNA by themselves would not be life, since it’s not enough to just join the bases (‘letters’) together, but the sequence of the letters must consitute meaningful information.
Even this letter sequence would be meaningless without elaborate decoding machinery to translate this into amino acid sequences.
Chemisynthesis is employed by organisms that live in the environment around deep-sea volcanic vents, where hot, hydrogen sulfide-rich waters pour out of newly formed ocean crust. Such waters, compared to the colder, sulfide-poor adjacent regions, have an abundant supply of free energy. This term refers to a source of energy that can be utilized readily to do some form of work, such as sustain biological processes, or can be stored in high-energy phosphate bonds. One readily available means to extract energy from the vents is to combine hydrogen sulfide with oxygen to form sulfur dioxide with production of energy. Such a process is possible in an ocean that has free oxygen available, but would not work on the primitive, pre-oxygen-rich Earth. Other biochemical cycles that use sulfur but not oxygen are conducted by some prokaryotic organisms, but these capture much less energy than the oxygendriven cycles. As with fermentation, chemisynthesis without free oxygen was the hallmark of a rather sluggish primitive biota.
Further problems:
There would have had to exist a cell membrane, dividing the outside from the inside of the proto-cell, to protect the chemical reactions, and complex gates regulating the compound entrance into the cell. That is another serious problem for origin of life research:
even in the simplest cells, the membrane is a biological device of a staggering complexity that carries diverse protein complexes mediating energy-dependent – and tightly regulated - import and export of metabolites and polymers Remarkably, even the author of the book: Agents Under Fire: Materialism and the Rationality of Science, pgs. 104-105 (Rowman & Littlefield, 2004). HT: ENV. asks the readers:
Hence a chicken and egg paradox: a lipid membrane would be useless without membrane proteins but how could membrane proteins have evolved in the absence of functional membranes?
The book Origins of Life on the Earth and in the Cosmos tries to solve the ridde as follows :
Membrane-enclosed cells came into being some time after the first ribozymes and definitely before the advent of translation systems. It is highly likely that these primitive living systems were sequestered in some way, possibly by adhering to clay surfaces. It is also likely that the first fatty acids used to make cellular membranes were made under conditions that would have been too harsh to share with living systems that are far more delicate. In view of this we must ask how the first membranes made contact with the early membrane- free living systems. How could life exist without membranes ?
Then we must consider how the early living systems became enclosed by these membranes and how the membranes of these most primitive cells evolved. True. Big questions, isnt it?
The encapsulation of the living systems into the liposomes was probably a simple process that required no more than one or two dry–wet cycles.
The pseudo-scientific just so stories are remarkable, aren’t they ?! The conclusion is that naturalistic explanations do not suffice to answer the relevant question in a satisfying manner, where Glucose came from, adding to all other unbridgeable problems of origin of life research, and thus giving proponents of intelligent design good reasons to infer intelligent design as the better explanation.
Science is about establishing what you can know and working forward from there.
You come at this looking for pieces to pick apart - yet it’s all done intentionally to deny facts.
On top of that you rely on others for all your arguments.
You have no interest in understanding the centuries long intellectual pageant of the process of discovery and understanding,
too busy trying defend what ever notions someone else has convinced you to accept. Unidirectional Skepticism Equals Denial
http://sandwalk.blogspot.com/2016/01/where-did-glucose-come-from.html
Where did the glucose come from?
The other view is the one supported by the majority of experts and people who make a serious study of the origin of life. It proposes a "metabolism first" view where the initial products of non-enzymatic reactions were small molecules like pyruvate and glycine and gradually pathways evolved to make the more complex molecules like glucose, more complex amino acids, and nucleotides. The energy for these reactions came from proton gradients in the pores of hydrothermal vents. In this view, life arose in tiny compartments, where concentrations could be significant, then spread to the ocean. [Changing Ideas About The Origin Of Life] [Was the Origin of Life a Lucky Accident?] [Why Are Cells Powered by Proton Gradients?] [Metabolism First and the Origin of Life].
In biochemistry courses we distinguish between catabolic pathways where something is broken down or degraded (= catabolism) and anabolic pathways where complex molecules are synthesised (= biosynthesis, anabolism). Glycolyis—the breakdown of glucose to pyruvate—is the classic example of catabolism. Gluconeogenesis—the synthesis of glucose from pyruvate—is the classic anabolic (biosynthesis) pathway. Similar contrasting pathways exist for amino acid metabolism and nucleotide metabolism.
Evolution of glucose utilization: Glucokinase and glucokinase regulator protein
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3897444/
Abstract
Glucose is an essential nutrient that must be distributed throughout the body to provide energy to sustain physiological functions. Glucose is delivered to distant tissues via be blood stream, and complex systems have evolved to maintain the levels of glucose within a narrow physiological range. Phosphorylation of glucose, by glucokinase, is an essential component of glucose homeostasis, both from the regulatory and metabolic point-of-view. Here we review the evolution of glucose utilization from the perspective of glucokinase. We discuss the origin of glucokinase, its evolution within the hexokinase gene family, and the evolution of its interacting regulatory partner, glucokinase regulatory protein (GCKR). Evolution of the structure and sequence of both glucokinase and GCKR have been necessary to optimize glucokinase in its role in glucose metabolism.
Keywords: Glucokinase (GCK), Hexokinase (HK), Glucokinase regulatory protein (GCKR), Liver, Glucose
If you want some fun learning, try that one guy, way more compelling (or do I mean entertaining) reading than that dusty old garbage you keep quoting without even understanding it yourself or being able to defend, beyond another huge cut and paste.
Oh and there are the many YouTube talks and a documentary by Robert Hazen
ROBERT HAZEN - CHANCE, NECESSITY, AND THE ORIGINS OF LIFE
https://www.youtube.com/watch?v=TlAQLgTwJ_A
CarnegieInstitution
Streamed live on Nov 12, 2015
NOTE: the lecture begins at the 13:20 minutes mark.
Earth's 4.5 billion year history is a complex tale of deterministic physical and chemical processes, as well as "frozen accidents". Most models of life's origins also invoke chance and necessity. Recent research adds two important insights to this discussion. First, chance versus necessity is an inherently false dichotomy--a range of probabilities exists for many natural events. Second, given the astonishing combinatorial chemical richness of early Earth, events that are extremely rare may, nevertheless, be deterministic on time scales of a billion years.
Robert Hazen, Geophysical Laboratory, Carnegie Institution for Science
https://www.youtube.com/watch?v=nk_R55O24t4
Published on Jan 20, 2015
Full Title: A new model for the origin of life: Coupled phases and combinatorial selection in fluctuating hydrothermal pools
Hydrothermal fields on the prebiotic Earth are candidate environments for biogenesis. We propose a model in which molecular systems driven by cycles of hydration and dehydration in such sites undergo chemical evolution and selection in a dehydrated surface phase followed by encapsulation and combinatorial selection in a hydrated phase. This model is partly supported by recent science, and lies partly in the realm of speculation including a hypothesized pathway for the parallel evolution of the functional machinery of life. Complex models like this present challenges for science in the 21st century and we will describe a new technology to enable the simulation of such models.
The conclusion is that naturalistic explanations do not suffice to answer the relevant question in a satisfying manner, where Glucose came from, adding to all other unbridgeable problems of origin of life research, and thus giving proponents of intelligent design good reasons to infer intelligent design as the better explanation.
I think it's fascinating the way you keep on demanding that we explain HOW all these things evolved by natural processes. And yet your only alternative is "Design". But when we ask in turn HOW this designer did it, suddenly that question is off limits! :)
I was puttering around, with Hazen’s talk playing in the background and it just occurred to me how much time Hazen spends explaining what we don’t know.
Then he goes on to strategize about the best kinds of experiments to perform to get us closer to an answer.
That is what science and honest learning is about. It’s not about plastering the walls with someone else’s flailings
Science and the genuine humanist desire to learn about this world we find ourselves in, is a refreshing life long hunt for discovery and ever richer understanding
we know it will never be complete, but find beauty in that- quite different from the Faith-Based with their NEED FOR ABSOLUTISM.
A’s type is reduced to playing rhetorical games and striving to develop gotchas, thinking that’s the fulfillment of their intellectual duty.
That sort of approach is not about achieving enlightenment or understanding about how our world works or how it got to be how it is,
you are a defender of dogma and know not what you speak of, because you’ve never dared look beyond the veil the way most of us at this board do.
This stuff is way over his head, CC. Much easier to believe nonsense than study science.
True true, but the more I reflect on the failures of the past four decades, all of which paved this path to Vandals and treasonists being handed our government.
I believe the most fundamental was a
The acceptance of this sort of illusion as though it doesn't matter.
Specifically back to the 70s the
Jesus Freaks who's absolutism was accepted as okay in our modern enlightened world.
Not so much their absolutism, but that these delusionals actually believed they were dealing Universal Truth. And that has been given a pass.
No ever strove to drive home the point that there are Personal Truths and there are Universal Truths - there is the spiritual world and the physical world.
Gould came closest* to defining the distinction, but that was never more than an intellectual curiosity.
*But still far short of the fundamental distinction between Personal Truths for matters of faith and Universal Truths when it came to our physical world
which with it's billions of f-ing years in the making is clearly beyond an God who would visit humans.
It's okay to have one's Personal Truths with it's absolute right and wrong, black and white and nothing in between.
But we allowed them to transfer their Personal Truths into realms of the physical world where Universal Truths hold absolute sway, though we'll never get to fully understand them.
On NPR Breitbart is discussed as a great media success with Bannon a great strategist and highly qualified.
What the fuck about the fact that Breitbart traded in complete malicious fabrications intent to destroying people - yes he was successful but that makes him a societal criminal.
what about Breitbarts and Bannon absolute contempt for factual truth - when agenda and winning are all that matters because
these people are complete egomaniacs devoid of all empathy
Same old shtick. Adonia is just scoring points with his god (in his own mind), not engaging in discussion. Just to clue you in Ms. Adonnia - God doesn’t take kindly to such selfish behavior. (And least that’s what She told me).
Hydrothermal fields on the prebiotic Earth are candidate environments for biogenesis. We propose a model in which molecular systems driven by cycles of hydration and dehydration in such sites undergo chemical evolution and selection in a dehydrated surface phase followed by encapsulation and combinatorial selection in a hydrated phase. This model is partly supported by recent science, and lies partly in the realm of speculation including a hypothesized pathway for the parallel evolution of the functional machinery of life. Complex models like this present challenges for science in the 21st century and we will describe a new technology to enable the simulation of such models.
_______________________________
what about you quote the part of the papers that explain how glucose formed in the prebiotic earth ? just throw a few unrelated papers and say : look here, wont work.
Hydrothermal fields on the prebiotic Earth are candidate environments for biogenesis. We propose a model in which molecular systems driven by cycles of hydration and dehydration in such sites undergo chemical evolution and selection in a dehydrated surface phase followed by encapsulation and combinatorial selection in a hydrated phase. This model is partly supported by recent science, and lies partly in the realm of speculation including a hypothesized pathway for the parallel evolution of the functional machinery of life. Complex models like this present challenges for science in the 21st century and we will describe a new technology to enable the simulation of such models.
_______________________________
what about you quote the part of the papers that explain how glucose formed in the prebiotic earth ? just throw a few unrelated papers and say : look here, wont work.
What about you peeking beyond your blinders?
You want to know why big shot?
Because it don't make one fucking bit of difference to the reality that,
it started with hydrogen
by and by stars,
then further atoms,
then molecules,
Then Earth and again base elements
then conglomerations of molecules,
then organized conglomerations,
then complex organized units
then complex organized units that learned how to cooperate with each other.
The rest is history, er, evolution.
All those stages and many not listed are demonstrated through countless examples.
That every detail has yet to be enunciated,
doesn't make the fundamental reality of the fundamental march of evolution any less valid.
Besides, on top of that - What do you have to replace this beautiful exquisitely detailed, if not absolutely complete, storyline with?
a bunch of inconsistent blind guessing, such as that stuff you keep posting?
Hydrothermal fields on the prebiotic Earth are candidate environments for biogenesis. We propose a model in which molecular systems driven by cycles of hydration and dehydration in such sites undergo chemical evolution and selection in a dehydrated surface phase followed by encapsulation and combinatorial selection in a hydrated phase. This model is partly supported by recent science, and lies partly in the realm of speculation including a hypothesized pathway for the parallel evolution of the functional machinery of life. Complex models like this present challenges for science in the 21st century and we will describe a new technology to enable the simulation of such models.
_______________________________
what about you quote the part of the papers that explain how glucose formed in the prebiotic earth ? just throw a few unrelated papers and say : look here, wont work.
What about you peeking beyond your blinders?
You want to know why big shot?
Because it don't make one fucking bit of difference to the reality that,
it started with hydrogen
by and by stars,
then further atoms,
then molecules,
Then Earth and again base elements
then conglomerations of molecules,
then organized conglomerations,
then complex organized units
then complex organized units that learned how to cooperate with each other.
The rest is history, er, evolution.
All those stages and many not listed are demonstrated through countless examples.
That every detail has yet to be enunciated,
doesn't make the fundamental reality of the fundamental march of evolution any less valid.
Besides, on top of that - What do you have to replace this beautiful exquisitely detailed, if not absolutely complete, storyline with?
a bunch of inconsistent blind guessing, such as that stuff you keep posting?
you have still failed to provide a compelling explanation about how glucose could have emerged in a prebiotic earth . organisms have extremely sophisticated mechanisms to make it , as for example photosynthesis by cyanobacteria, and glyconeogenesis to keep homeostasis. There is no natural mechanism known to produce it without enzymes involved.....
I know about the evolutionary story based on all the things scientists have been able to discover a tease of the evidence.
I am no expert, not even slightly proficient as I dare say I am regarding our much much simpler global climate system, so stumping me is no great victory for you.
Although I took your question to about the only other forum I keep up with: https://chat.hotwhopper.com/discussion/216/non-climate-related-trivia-question-deep-evolution#latest
and received a response I think worth passing along.
hat tip to my pal the FlyingDutchman:
Arguments from complexity/incredulity are almost impossible to counter since they are based primarily on rejecting the complexity of reality itself and they can simply disagree with you by saying 'you don't know that for sure!'. Creating a chemical reaction scheme/flow chart is pointless since there's not *one* specific source of glucose. That said, based on the composition glucose would most likely have formed from a combination of less complex precursor molecules, which in turn were created from Carbon Monoxide/Dioxide, water, and probably some involvement from Nitrogen and/or Sulphur compounds as well even if there's no N/S atoms in the final product.
A quick google search leads me to believe glucose has been created chemically as early as the 19th century, by a guy called Hermann Fischer. Don't know if there's earlier evidence,
but simply showing him as an example should already work to show making glucose is *not* all that hard.
Also, I think this one might be useful, it's about amino acids and not glucose, but the same principle applies: https://www.ncbi.nlm.nih.gov/pubmed/16404523
Now if you actually want to learn about it, here’s an intro.
Published on Feb 27, 2013
UCI Chem 128 Introduction to Chemical Biology (Winter 2013)
Lec 14. Introduction to Chemical Biology -- Glycobiology
https://www.youtube.com/watch?v=yWWtoypJWQg
That's how science and learning works.
You start with what you know, and actively study and learn about the topic at hand until you understanding it better.
Not by tossing out gotcha questions, backed by absolutism and self-certainty, with not interest in examine the responses you get.
Now if you actually want to learn about it, here's an intro.
Published on Feb 27, 2013
UCI Chem 128 Introduction to Chemical Biology (Winter 2013)
Lec 14. Introduction to Chemical Biology -- Glycobiology
https://www.youtube.com/watch?v=yWWtoypJWQg
That's how science and learning works.
You start with what you know, and actively study and learn about the topic at hand until you understanding it better.
Not by tossing out gotcha questions, backed by absolutism and self-certainty, with not interest in examine the responses you get.
Read my reply above. Not sure why you or anybody engage guys like Adonnia. They're only here to score points with their god, not engage in discussion. By engaging them I think, not unlike Drumpf, we normalize them and make it seem as though they are in fact engaging in honest discussion when they're not.
Read my reply above. Not sure why you or anybody engage guys like Adonnia. They're only here to score points with their god, not engage in discussion. By engaging them I think, not unlike Drumpf, we normalize them and make it seem as though they are in fact engaging in honest discussion when they're not.
Agreed. The best thing with can do with this poster is ignore him.
Read my reply above. Not sure why you or anybody engage guys like Adonnia. They're only here to score points with their god, not engage in discussion. By engaging them I think, not unlike Drumpf, we normalize them and make it seem as though they are in fact engaging in honest discussion when they're not.
Agreed. The best thing with can do with this poster is ignore him.
This morning I agreed - but damnit all that's how we got into this good awful tea party / right wing religious political force / Trump shit hole mess to begin with ! >:-(
Ignoring it allowed them to an unimpeded path to Alternative Universe acceptance and mainstreaming.
Maybe A. will remain as stupid as obstinate as a brick wall - but there are others looking in.
Every one of these challenges can be meet, if not with a complete answer, at least a road map showing how questions are approached.rationally.
Case in Point if A cared at all, he should visit the following discussion, match his wits with folks who actually understand some of the details.
http://biology.stackexchange.com/questions/2934/why-is-glucose-our-primary-source-of-energyWhy is glucose our primary source of energy?
Is there any evolutionary reason for glucose being the "main" molecule used as a source of energy, beginning with glycolysis and subsequently cellular respiration (after being converted to two pyruvate molecules)? Or did this particular biochemical pathway arise "by fluke" early on in the history of life?
A colleague of mine told me that it was because as shown below, all of beta-D-glucose's hydroxyl substituents are all equatorially positioned (when in the correct chair conformation), which lends to its general stability.
Image taken from the Wikimedia Commons.
Could this have played a factor in the beginnings of energy metabolism, and if so, why?
I thought this was a great question. In particular because it hints at two questions. The first is 'why carbohydrates are used to store energy' in general. The second being 'why glucose rather than other carbohydrates?' in particular.
Glucose metabolism (and glycogen storage) is a core gene pathway - its found in bacteria archaea and eukaryotes. So probably the most that we can readily say about question one is that as @rwst points out this pathway has proven to be useful at a critical juncture of the formulation of living things on earth. If you look at glucose metabolism pathways, you can see that glycerate compounds and pyruvate are the actual intermediates that are used to create energy. The first thing about these molecule worth noting is that they have a good mix of carbon and oxygen, which would make it easier to extract energy - creating CO2 from these compounds may even predates the existence of atmospheric oxygen. So glucose and fructose (which is actually derived from glucose in the metabolic pathway) are actually storage molecules themselves, easily broken down to smaller molecules.
As to the second question: there are quite a few ways to arrange oxygen around the carbohydrate ring. why glucose? The advantages of glucose is probably a subtle one. The structural properties of glycogen might be a reason that the use of glucose monomer is so important for glycogen. There is no evidence that I can find for this, so its always possible that glucose was just the first hexose carbohydrate to be biologically used. Its sort of hard to imagine that the structure of glucose does not play some sort of role in cell structure though. ...
There are more comments and thoughts shared. The point in sharing this isn't that it provides a pat answer to A's challenge -
What it does show is that there are realistic constructive ways to approach such "mysteries" and that making a list of all the reasons you know it can't be true - isn't one of them.
you have still failed to provide a compelling explanation about how glucose could have emerged in a prebiotic earth . organisms have extremely sophisticated mechanisms to make it , as for example photosynthesis by cyanobacteria, and glyconeogenesis to keep homeostasis. There is no natural mechanism known to produce it without enzymes involved.....
And you have still failed to provide any explanation at all, compelling or not, for how "design" by itself is somehow magically a solution to the question. You might as well say "blitiri". How did glucose emerge from the prebiotic earth? Blitiri! It's as plain as the nose on your face! :)
The conclusion is that naturalistic explanations do not suffice to answer the relevant question in a satisfying manner, where Glucose came from, adding to all other unbridgeable problems of origin of life research, and thus giving proponents of intelligent design good reasons to infer intelligent design as the better explanation.
I think it's fascinating the way you keep on demanding that we explain HOW all these things evolved by natural processes. And yet your only alternative is "Design". But when we ask in turn HOW this designer did it, suddenly that question is off limits! :)
That's because a designer uses magic. With magic anything is possible--except evolution.