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    Can someone explain the Meselson and Stahl experiment? I need another perspective on this
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    Was revising this earlier.
    1)they werent sure whether DNA replicated conservatively (made a new strand from itself) or semi conservatively.
    2) Put seperate bacteria in a heavy nitrogen (n15) solution and a light nitrogen n(14) solution.
    3)Then took a sample of the bacteria(from both solutions) out and spun it in a centrifuge.
    4)The nitrogen solution is absorbed by the nitrous bases (i think) and hence the n15 heavy settles lower in the centrifuge tube as it is heavier..
    5)They then take the bacteria out heavy nitrogen solution/broth and put in the light nitrogen broth.
    6)left for a round of replication
    7)centrifuge again
    8)so if replication was conservative , the heavy nitrogen bacteria would replicate itself and would settle at the bottom while the light bacteria would be at the top - the same as before.
    9)but the dna settled in the middle , containing a strand of heavy and light nitrogen.
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    (Original post by boinz)
    Was revising this earlier.
    1)they werent sure whether DNA replicated conservatively (made a new strand from itself) or semi conservatively.
    2) Put seperate bacteria in a heavy nitrogen (n15) solution and a light nitrogen n(14) solution.
    3)Then took a sample of the bacteria(from both solutions) out and spun it in a centrifuge.
    4)The nitrogen solution is absorbed by the nitrous bases (i think) and hence the n15 heavy settles lower in the centrifuge tube as it is heavier..
    5)They then take the bacteria out heavy nitrogen solution/broth and put in the light nitrogen broth.
    6)left for a round of replication
    7)centrifuge again
    8)so if replication was conservative , the heavy nitrogen bacteria would replicate itself and would settle at the bottom while the light bacteria would be at the top - the same as before.
    9)but the dna settled in the middle , containing a strand of heavy and light nitrogen.
    Thank you so much!! I think you've managed to help me clear things up a little
 
 
 
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