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Where did Glucose come from in a prebiotic world ?
Posted: 02 February 2017 09:52 PM   [ Ignore ]   [ # 16 ]
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DarronS - 02 February 2017 11:01 AM
CuthbertJ - 02 February 2017 10:58 AM

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 !  angry

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-energy

Why 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.

620px-Beta-D-Glucose.svg.png
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.

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Posted: 03 February 2017 08:25 AM   [ Ignore ]   [ # 17 ]
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Adonai888 - 02 February 2017 05:00 AM

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!  smile

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Posted: 03 February 2017 11:53 PM   [ Ignore ]   [ # 18 ]
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Advocatus - 01 February 2017 09:20 AM
Adonai888 - 31 January 2017 02:14 PM

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!  smile

That’s because a designer uses magic. With magic anything is possible—except evolution.

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[color=red“Nothing is so good as it seems beforehand.”
― George Eliot, Silas Marner[/color]

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