Ch.16 - DNA SynthesisWorksheetSee all chapters
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Solution: if Meselson and Stahl had first grown the cells in 14N-containing medium and then moved them into 15N-containing medium before taking samples, what would have been the result after each of the two rep

Problem

if Meselson and Stahl had first grown the cells in 14N-containing medium and then moved them into 15N-containing medium before taking samples, what would have been the result after each of the two replications?


Solution

Meselson and Stahl came up with an experiment to deduce the mechanism for DNA replication. They cultured E.coli in a medium containing nucleotide precursors labeled with 15N and transfer them to a medium containing 14N before taking samples after the first and second replication. 

If the culture was first grown with th lighter isotope (14N) isotope before being transferred to the heavier (15N) isotope prior to sample collection, the result of the first replication would be a DNA with a 50:50 hybrid containing both isotopes (14N-15N), just like that of the original experiment.

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