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James Tour on carbohydrate synthesis

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  • James Tour on carbohydrate synthesis

    Spoiler: it's really hard...

    James Tour goes into how hard it is to get just D-ribose synthesized in early earth conditions, a dozen steps or more, and you just get racemic ribose at about 6% yield. Then you need to stop the reaction, otherwise it all degrades in a couple of years (a blink of an eye in abiogenesis). Then you need to purify it, then you need to hook them together (there's a huge number of ways to hook them together, and only one of them is the desired product).



    Blessings,
    Lee
    Last edited by lee_merrill; 03-05-2021, 03:01 PM.
    "What I pray of you is, to keep your eye upon Him, for that is everything. Do you say, 'How am I to keep my eye on Him?' I reply, keep your eye off everything else, and you will soon see Him. All depends on the eye of faith being kept on Him. How simple it is!" (J.B. Stoney)

  • #2
    This is Lee's standard garbage. "Watch this 45 minute video or i'll feel justified in claiming you guys never address anything".

    How about this instead: make an argument for yourself for a change. Do the work instead of demanding that everyone BUT you put in effort here.
    "Any sufficiently advanced stupidity is indistinguishable from trolling."

    Comment


    • #3
      Originally posted by TheLurch View Post
      This is Lee's standard garbage. "Watch this 45 minute video or i'll feel justified in claiming you guys never address anything".

      How about this instead: make an argument for yourself for a change. Do the work instead of demanding that everyone BUT you put in effort here.
      I watched the video, and gave summary, making carbohydrates is hard: "James Tour goes into how hard it is to get just D-ribose synthesized in early earth conditions, a dozen steps or more, and you just get racemic ribose at about 6% yield. Then you need to stop the reaction, otherwise it all degrades in a couple of years (a blink of an eye in abiogenesis). Then you need to purify it, then you need to hook them together (there's a huge number of ways to hook them together, and only one of them is the desired product)."

      Do you have a way to make carbohydrates in early-earth conditions? They are essential for life, says Tour.

      Blessings,
      Lee
      "What I pray of you is, to keep your eye upon Him, for that is everything. Do you say, 'How am I to keep my eye on Him?' I reply, keep your eye off everything else, and you will soon see Him. All depends on the eye of faith being kept on Him. How simple it is!" (J.B. Stoney)

      Comment


      • #4
        Originally posted by lee_merrill View Post
        I watched the video, and gave summary, making carbohydrates is hard: "James Tour goes into how hard it is to get just D-ribose synthesized in early earth conditions, a dozen steps or more, and you just get racemic ribose at about 6% yield. Then you need to stop the reaction, otherwise it all degrades in a couple of years (a blink of an eye in abiogenesis). Then you need to purify it, then you need to hook them together (there's a huge number of ways to hook them together, and only one of them is the desired product)."

        Do you have a way to make carbohydrates in early-earth conditions? They are essential for life, says Tour.

        Blessings,
        Lee
        So pretty much what Tour has been saying for, what, over a decade now?

        I'm always still in trouble again

        "You're by far the worst poster on TWeb" and "TWeb's biggest liar" --starlight (the guy who says Stalin was a right-winger)
        "Of course, human life begins at fertilization thatís not the argument." --Tassman

        Comment


        • #5
          Originally posted by rogue06 View Post
          So pretty much what Tour has been saying for, what, over a decade now?
          Well, this is new to me, I haven't seen him talk about carbohydrate synthesis before.

          Blessings,
          Lee
          "What I pray of you is, to keep your eye upon Him, for that is everything. Do you say, 'How am I to keep my eye on Him?' I reply, keep your eye off everything else, and you will soon see Him. All depends on the eye of faith being kept on Him. How simple it is!" (J.B. Stoney)

          Comment


          • #6
            Originally posted by lee_merrill View Post
            I watched the video, and gave summary, making carbohydrates is hard: "James Tour goes into how hard it is to get just D-ribose synthesized in early earth conditions, a dozen steps or more, and you just get racemic ribose at about 6% yield. Then you need to stop the reaction, otherwise it all degrades in a couple of years (a blink of an eye in abiogenesis). Then you need to purify it, then you need to hook them together (there's a huge number of ways to hook them together, and only one of them is the desired product)."
            Actually, a number of researchers have demonstrated pathways that synthesize full nucleotides - sugars plus bases - without requiring the synthesis of a sugar as an intermediate. Thus, if this is Tour's entire argument, then he's either not up on the relevant literature, or this whole video's a 45 minute misdirection.

            Which is why i wanted more than a summary out of you.

            But of course, having you know anything at all about the relevant scientific literature regarding what you post is being completely unrealistic on my part. As is seeing you find any fault with an argument you would prefer to believe.
            "Any sufficiently advanced stupidity is indistinguishable from trolling."

            Comment


            • #7
              Originally posted by TheLurch View Post
              Actually, a number of researchers have demonstrated pathways that synthesize full nucleotides - sugars plus bases - without requiring the synthesis of a sugar as an intermediate.
              But Tour is talking about synthesis of carbohydrates, not nucleotides. And he goes into what other scientists have done, and it's very little.

              Blessings,
              Lee
              "What I pray of you is, to keep your eye upon Him, for that is everything. Do you say, 'How am I to keep my eye on Him?' I reply, keep your eye off everything else, and you will soon see Him. All depends on the eye of faith being kept on Him. How simple it is!" (J.B. Stoney)

              Comment


              • #8
                Originally posted by lee_merrill View Post
                But Tour is talking about synthesis of carbohydrates, not nucleotides. And he goes into what other scientists have done, and it's very little.
                He's talking about synthesizing them abiotically. But if you can make nucleotides without them, then you can start life without them. And then they don't have to by synthesized abiotically.
                "Any sufficiently advanced stupidity is indistinguishable from trolling."

                Comment


                • #9
                  Originally posted by TheLurch View Post
                  He's talking about synthesizing them abiotically. But if you can make nucleotides without them, then you can start life without them. And then they don't have to by synthesized abiotically.
                  But the first proto-cell will need carbohydrates, particularly in the cell wall. These would need to be synthesized abiotically.

                  "If you get the carbohydrates wrong, the cell dies." (James Tour)

                  Blessings,
                  Lee
                  "What I pray of you is, to keep your eye upon Him, for that is everything. Do you say, 'How am I to keep my eye on Him?' I reply, keep your eye off everything else, and you will soon see Him. All depends on the eye of faith being kept on Him. How simple it is!" (J.B. Stoney)

                  Comment


                  • #10
                    Originally posted by lee_merrill View Post
                    But the first proto-cell will need carbohydrates, particularly in the cell wall. These would need to be synthesized abiotically.

                    "If you get the carbohydrates wrong, the cell dies." (James Tour)
                    The first cells were overwhelmingly unlikely to have cell walls.

                    And Tour there is talking about a current cell, so that's irrelevant.
                    "Any sufficiently advanced stupidity is indistinguishable from trolling."

                    Comment


                    • #11
                      Originally posted by TheLurch View Post
                      The first cells were overwhelmingly unlikely to have cell walls.

                      And Tour there is talking about a current cell, so that's irrelevant.
                      That's something that always got to me about the criticism of abiogensis. No one suggests that the first cells would be remotely like modern cells.
                      “I like your Christ, I do not like your Christians. Your Christians are so unlike your Christ.”

                      -Ghandi (Disputed)

                      Comment


                      • #12
                        Originally posted by lee_merrill View Post
                        But the first proto-cell will need carbohydrates, particularly in the cell wall. These would need to be synthesized abiotically.

                        "If you get the carbohydrates wrong, the cell dies." (James Tour)
                        No. The first proto cells almost certainly had cell membranes, not cell walls. Cell membranes are lipid bilayers, which form naturally and do not contain carbohydrates.

                        Comment


                        • #13
                          Originally posted by rossum View Post
                          The first proto cells almost certainly had cell membranes, not cell walls. Cell membranes are lipid bilayers, which form naturally and do not contain carbohydrates.
                          Well, I did mean membranes, and "Membrane-bound glycoproteins participate in a wide range of cellular phenomena, including cell recognition, cell surface antigenicity, etc." (Microbe Notes) and "Glycolipids help maintain the stability of the cell membrane and facilitate cell-cell interactions." (Great Essays)

                          Blessings,
                          Lee
                          Last edited by lee_merrill; 03-07-2021, 05:10 PM.
                          "What I pray of you is, to keep your eye upon Him, for that is everything. Do you say, 'How am I to keep my eye on Him?' I reply, keep your eye off everything else, and you will soon see Him. All depends on the eye of faith being kept on Him. How simple it is!" (J.B. Stoney)

                          Comment


                          • #14
                            Originally posted by lee_merrill View Post
                            Well, I did mean membranes, and "Membrane-bound glycoproteins participate in a wide range of cellular phenomena, including cell recognition, cell surface antigenicity, etc." (Microbe Notes) and "Glycolipids help maintain the stability of the cell membrane and facilitate cell-cell interactions." (Great Essays)
                            Man, you'll just throw anything out without any thought whatsoever if your gut tells you it sounds like it supports your argument.

                            An essay at "https://great-home-decorations.com"? Seriously?

                            Even beyond the quality of your sources, you're just posting a bunch of irrelevant stuff. In the RNA world, there weren't any proteins around, so what do you think the need for glycosylated proteins was? I expect an answer to that question. Or an apology for wasting everybody's time by making arguments that are on the face of things completely nonsensical.

                            Glycolipids do pay valuable functions in today's cells. But they're involved in sophisticated processes that almost certainly did not exist in the first cells, since membranes work just fine without them. Remember, we're talking origin of life, not "useful function in immunity in multicellular organisms".

                            If you want a relevant argument, you need to identify a function for carbohydrates that is absolutely essential to the operation of a primitive, RNA-world style cell. Again, the obvious one is as a building block of RNA. But, as mentioned above, chemistry has indicated you don't need to independently synthesize a sugar to generate nucleotides.


                            The other question i would like an answer to is whether Tour at any point in those 45 minutes mentions the fact that we can synthesize RNA nucleotides without sugars. Because if he didn't, he is misleading you.
                            "Any sufficiently advanced stupidity is indistinguishable from trolling."

                            Comment


                            • #15
                              Originally posted by TheLurch View Post
                              In the RNA world, there weren't any proteins around, so what do you think the need for glycosylated proteins was?
                              Well eventually you need to get to proteins. But I will grant you that the RNA world need not have proteins.

                              If you want a relevant argument, you need to identify a function for carbohydrates that is absolutely essential to the operation of a primitive, RNA-world style cell.
                              How about here?

                              Source: Wikipedia

                              Glycolipids are lipids with a carbohydrate attached by a glycosidic (covalent) bond.[1] Their role is to maintain the stability of the cell membrane and to facilitate cellular recognition, which is crucial to the immune response and in the connections that allow cells to connect to one another to form tissues.

                              Source

                              © Copyright Original Source


                              Maintaining the stability of the membrane would seem to be a critical need.

                              The other question i would like an answer to is whether Tour at any point in those 45 minutes mentions the fact that we can synthesize RNA nucleotides without sugars. Because if he didn't, he is misleading you.
                              No, he didn't mention that, but why are OOL researchers attempting to create sugars if there is this easier route available?

                              Blessings,
                              Lee
                              "What I pray of you is, to keep your eye upon Him, for that is everything. Do you say, 'How am I to keep my eye on Him?' I reply, keep your eye off everything else, and you will soon see Him. All depends on the eye of faith being kept on Him. How simple it is!" (J.B. Stoney)

                              Comment

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