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Homework Help: Question about Deuterium Oxide and feeding it to flies? (Some general questions)

  1. Oct 26, 2012 #1
    Questions about "Heavy Water" and vibration...Thank you!

    Hey everyone,

    I am hoping someone can help explain something to me.

    Some biology students wanted to conduct research, and I don't quite understand a few things (as I think they are not correct, but I am not a biology student)

    My first question: They want to feed flies some "Heavy Water" and see how it affects their daily clock in terms of activity. The aim is that different sources of "Heavy Water" will have different vibration, and that vibration will interact with receptors different, based solely on the vibration quality of each of the 3 different sources of "Heavy Water"....In terms of quantum biology

    1st question: Why would they use heavy water????? (if they are just wanting to see if different vibrations of molecules act differently on the flies)

    2) What would give me 3 samples of water, each with different vibrations? Could it not just be different temperatures ? Since cold, warm, hot water will have different vibrating molecules?

    BIG QUESTION :) ........ From a quantum physics standpoint, how could I use quantum theory to test if a receptor will act different on a quantum level???
  2. jcsd
  3. Oct 26, 2012 #2
    How much Deuterium Oxide would be safe to give a fly?

    Is there a chart/formula for levels of safe Heavy Water?
  4. Oct 26, 2012 #3
    Please help explain question about molecule (Deuterium Oxide)

    1. The problem statement, all variables and given/known data

    So, someone feeds a fly some Deuterium Oxide. They hope that if they have 2 different samples of Deuterium Oxide, with each of them with different Vibration rates, they will react differently with the flies?

    2. Relevant equations

    3. The attempt at a solution

    I do not understand in what way the Deuterium Oxide would interact with fly? Does each Deuterium Oxide molecule interact with a cell receptor, and thats how the Deuterium Oxide is used by the fly?

    Mainly, what is the process in which the fly utilizes the Deuterium Oxide, or heck, what is the process a fly would use water it drinks????
  5. Oct 26, 2012 #4

    jim mcnamara

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    There is no published LD50 value for heavy water or MSDS warning for it. It is not radioactive. Humans have consumed it reasonable quantities, in larger quantities it does become slightly toxic: when total organism water content is ~50% heavy water.

    So the answer is I do not know of any such chart. google for 'heavy water' and 'Drosophila' and do some reading. There have been several papers on fruit flies and heavy water. Maybe there is some help in there.

    Out of curiosity: Are to trying to increase the density of the fly? Maybe see how a heavy fly is able to fly (or not)? Might be interesting...
  6. Oct 26, 2012 #5


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    << Moderator note -- multiple threads on the same subject merged... >>
  7. Oct 26, 2012 #6
    No, they are not trying to increase the density, although I do agree that sounds interesting.

    They are feeding flies 3 different samples of Deuterium Oxide.

    However they keep saying that they want each sample of Deuterium oxide to have a different vibration level. What does that even mean? How and why would you want Deuterium's molecules to vibrate at a different level?

  8. Oct 26, 2012 #7


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    I did a Google search on the title of your thread (with some extra words removed), and it looks like the correct term is "vibrational", and it has something to do with the electronic structure of the molecule:


  9. Oct 26, 2012 #8


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    What the words mean is that the vibration frequency of a bond like with heavy hydrogen C-D is lower than that of C-H. A chemical reaction involving breakage of the C-H bond is considerably slower with C-D (ideally 7X). The substitution will change equilibrium constants.

    I do not know how anyone is going to interpret experiments, to identify a mechanism of anything through an experiment in which they change everything in the organism. OK not everything, but the water and everything that overturns metabolically to incorporate the D in a few days. Isotope effects are interpretable at the level of study of the mechanism of a single enzyme as far as I know. Unless there is some idea I can't guess I would call this experiment a waste of time.

    I did a very long time ago hear of someone very excited the results of some such experiments - and that the effects were traced to metal ions leached out of the containers of the D2O !

    More interesting is that there have been many applications in archaeology and deep past earth history of the isotope effect, since as things go through chemical and especially biochemical processes due to the above explained effects the isotope ratios are changed. That would be scientifically worthwhile your following up if interested (don't rely on it but as example I think the calcium or strontium isotope ratios in teeth, depending on how long a food chain was tells whether people's diet was fish or land diet).
  10. Oct 27, 2012 #9


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    Gibberish for me.

    If it is about vibrational levels you can't have samples with different vibrational levels, just like you can't have samples of water with different angle between hydrogen bonds, or with smaller molecules (and I have seen both things advertised). Yes, due to the fact mass of deuterium is different than the mass of protium, vibrational frequencies of bonds in the heavy water molecules will be different from those present in the normal water, and this difference would be easy to detect via spectroscopic methods. But they will not depend on the sample.

    Average values (if they make any sense) will depend of the sample composition, but if you have both water and heavy water, you can easily control compositions of samples just by diluting heavy water.
  11. Oct 27, 2012 #10


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    I'd guessed that was all they meant, but the strange way of saying it does justify scepticism.
  12. Oct 27, 2012 #11
    Epenguin and Borek, really appreciate the responses!

    So, am I correct in assuming that its impossible to have different vibrational qualities in 2 different samples of deuterium Oxide?

    Also... Am I correct in assuming that if I have 1 sample of Deuterium oxide, and I have another sample of Deuterium oxide, If I dilute one, it will have a different vibrational quality?

    What about temperature of the deuterium oxide? Would different temps of samples produce different vibrational qualities?

    Thanks so much

  13. Oct 31, 2012 #12


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    I see in a Wikipedia article on heavy water they do say that affects circadian periods of various animals and is the only substance known to do that. But then as I expected they say the explanation is not known.
    Oh well, if you get up to 50% substitution (100% is toxic) what are 50% of the water molecules? DOH!
    Last edited: Oct 31, 2012
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