DNA Molecular Biology Visualizations - Wrapping And Replication

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12 Responses:

  1. ultranurd says:

    I'm glad modern biochemistry has finally solved the problem of untangling telephone handset wires.

  2. benchilada says:


    Even my fucking molecules have Tourette's.

  3. gfish says:

    I'm made out of deterministic machines? Woohoo! Time for an nihilistic orgy of senseless violence!

  4. merovingian says:

    "Then, twitchy purple bug monsters attack your DNA."

  5. 205guy says:

    This is so cool. Thank you supercomputers (and molecular biologists who can actually say "cranking out").

    Now for my questions:

    - Is the error rate different between the "continuously forward" copy and the piecemeal backwards copy?

    - What prevents the second copy from being copied bacwards, is it something with how the molecules fit together?

    - Do you think humans will ever get to the point where they can "hack" these molecules to be more accurate, efficient, or do wacky stuff? (I guess those animations make it look easy.)

    • eeege says:

      - In my cell biology course we learned that mix ups happen both ways with the same amt of error. (But I only have a bachelors and haven't done indepth study on this.)

      - Iirc, the DNA separates in several places at once during replication. Kinda like that zipper you had on your 3rd grade winter coat that is closed at the top and at the bottom but somehow the middle is wide open. The replication continues until it meets another DNA polymerase. (or until it gets to the telemeres (end of the strand) For proteins there are 'codes' in the DNA that tell where to start. This is for making m-RNA.

      - Humans already 'hack' into DNA. Its called Gene Therapy. See, there are viruses that can already 'hack' into our DNA and do bad things to us. We're learning how to remove the DNA/RNA inside the 'bad' virus and replace it with DNA/RNA that fixes errors or turns on/off a gene thereby making it a 'good' virus.

      I'm sorry if I'm long-winded, I can go on and on about Biology.

      • 205guy says:

        Interesting about the equality errors. I guess I am really fascinated with how the protein molecules (DNA polymerase and others) interact mechanically and electromagnetically with the DNA strand. It seems that whenever you have a discontinuity or a change in the way to handle a steady input, as when the backwards copying meets the next piece or when one DNA polymerase meets the next, you have a more complex interaction and therefore more chance for error.

        Another question about errors: how is the supply of DNA constituent proteins managed so that the copying can go so fast? I imagine they are floating around in high concentrations and binding to the polymerase to be incorporated, but is there a queue or throttle of some sorts?

        The hacking I meant was to the DNA polymerase. If one direction had been more error-prone, I thought humans could invent a DNA polymerase 2.0 that somehow managed to copy both strands forwardly.

        What's more dangerous than a software developer with a screwdriver? One with notions of molecular biology...

        • eeege says:

          Well, I'll do my best here. Some of this is out of my league.

          Basically, DNA polymerase 'checks' itself to make sure there isn't a mistake before it continues. (I think it's the most accurate enzyme.) If it finds that error, it kinda goes backwards and fixes it before it puts on the next nucleotide. That's not to say errors don't occur, but considering you're here and you basically fully regenerate every 7 years, it does a pretty good job.

          Also, if you understand how these translate into proteins, then you understand that one error isn't gonna do much. If CUU and CUC (RNA made from the DNA) both code for Leucine, then you'll see that the error has very little impact.

          As for a queue, I don't know the answer to that question. I took a cell biology class which goes over most of this but not into great detail. I believe it has something to do with the fact that the sizes are different (purine vs pyrimidine) as well as the charges. Dunno if I should go into length here, but if you're constructing a four step ladder and you have four short pieces of rung and four long pieces of rung, you'll need to pair a short piece with a long piece to ensure the rung sizes all match up.

          As for doing them both forwardly, well, if it isn't broken. . .


  6. wisedonkey says:

    Intelligent design my ass. Based on the dna copying scheme, it looks to me like we were created by a biomechanical engineering dropout that fluffed his resume and got hired at some giant extra-dimensional corporation that's cutting corners to be "productive."

  7. bax says:

    That was awesome.