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What would DNA look like?

  1. Nov 6, 2006 #1
    What would a mole of mammal DNA look like? Smell like? Feel like?

    How about a mole of plant DNA?
     
  2. jcsd
  3. Nov 6, 2006 #2
    To have a mole of something you need a finite number of regular molecules. 6.022*10^23 to be exact. DNA comes in long chains or little snippets, and depending on its nucleotide makeup would come in different molecular weights even if it was of uniform length. So I don't know if you can even have a 'mole of DNA' in the general sense.
     
  4. Nov 6, 2006 #3

    chroot

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    When it's extracted from cells in preparation for sequencing or PCR, it looks a lot like, well, snot.

    - Warren
     
  5. Nov 7, 2006 #4
    In regards to looking like snot, I don't think there would be much difference between plant and animal DNA. Feels? Probably slimey.
     
  6. Nov 7, 2006 #5
    So maybe I should have stated a mole of human DNA and a mole of cauliflower DNA. Because each species have very similar DNA and each cell in an individual entity such as human have the same length, size DNA but only choose to read a segment of it (This DNA was formed when the person first formed and became a zygote cell). How many moles of cells in a human? So it should be attainable.
     
  7. Nov 7, 2006 #6

    chroot

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    pivoxa,

    DNA is molecule with variable length. Some pieces of DNA are quite long, while some can be quite short. Thus, it makes no sense to talk about "a dozen DNA," nor does it make sense to talk about "a mole of DNA."

    Either way, your question is just asking about the physical qualities of a large amount of pure DNA, and doesn't really depend on the interpretation of the word "mole."

    - Warren
     
  8. Nov 7, 2006 #7

    What colour?

    Do most single type proteins in mass look like this?
     
  9. Nov 7, 2006 #8
    So just say in a human, you say there are many different types of DNA? Is that because there are 23 pairs of different chromosomes and the DNA in them are different? Are all these different types present in the zygote cell? How many different types are there?
     
  10. Nov 7, 2006 #9

    chroot

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    It's a cloudy whitish color.

    - Warren
     
  11. Nov 7, 2006 #10

    chroot

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    There are 23 pairs of chromosomes, each of different length, and the code carried by each is indeed different. Furthermore, when you extract DNA, you necessarily damage it. What you end up with is not 23 pairs of nice tidy complete DNA strands -- you end up with a mush of millions of broken pieces of DNA of all different lengths. Then you use a gene sequencing machine (and a supercomputer) to fit the jigsaw puzzle back together again.

    - Warren
     
  12. Nov 7, 2006 #11

    arildno

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    Isn't snot green by definition? :confused:
     
  13. Nov 7, 2006 #12

    chroot

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    Only if you've got a cold, I think.

    - Warren
     
  14. Nov 8, 2006 #13

    jim mcnamara

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    "green" means sinusitis. arildno - do you have some kind of perennial infection?
     
  15. Nov 8, 2006 #14

    arildno

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    Not really. At other times, thiough, I would call it "icky-stuff-from-the-nose", rather than "snot".:redface:
     
  16. Nov 8, 2006 #15

    Phobos

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    The PBS documentary "Journey of Man" by Spencer Wells shows this in one scene. (great show, BTW)
     
  17. Nov 9, 2006 #16

    Moonbear

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    Maybe dried snot. :confused: If there are no salts or proteins contaminating the preparation, it's actually darned hard to see when completely isolated. Usually just a clear-ish speck on the bottom of the tube that you can only be sure is there when you start reconstituting it with water and see where the water flow changes (in the 10-100 microgram range...how many moles would depend on the size of the DNA strand, which varies with species, but a LOT). Salts in your preparation will leave the pellet looking a bit cloudier...easier to see, but not pure (and then the folks that do the sequencing for you yell at you and send it back to be purified better :grumpy:).
     
  18. Nov 10, 2006 #17

    jim mcnamara

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    Moonbear - the voice of experience?
     
  19. Nov 10, 2006 #18

    Monique

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    That is after you have spun it down. When you lyse cells and the DNA is released, you get very long snotty fibers of DNA. Samples of genomic DNA that have a high concentration can be hard to pipet because of the snotty nature of the sample.
     
    Last edited: Nov 10, 2006
  20. Nov 10, 2006 #19

    Moonbear

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    Oops, I realized that I've only dealt with plasmid DNA (to ultimately use as templates for making probes for in situ hybridization), and throw away the snotty genomic DNA in everything I do, so forgot about what that part looks like; I have better recollection of those stubborn pellets. :redface:
     
  21. Nov 15, 2006 #20
    I'm really digging our highly intellectual discussions of snot. :rofl:
     
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