Chapter:

Molecular-Basis-of-Inheritance

E. coli bacteria grew in a nutrient solution containing a heavy, stable isotope of nitrogen, . It is n transferred to a medium with more common light isotope of nitrogen. Then DNA from cells was extracted and subjected to density centrifugation. The strain of E. coli used to divides once every 20 minutes. The results are illustrated below, heaviest DNA is extracted from cells at

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