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(vIsotopes used in proving semi-conservative replication of DNA werea) WN,4cc) 4N, 15Nb) WC, 1Pd) "N, TP |
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Answer» Answer: c)14N,15NExplanation:Meselson and Stahl conducted their famous experiments on DNA replication using E. coli bacteria as a model system.They began by growing E. coli in medium, or nutrient broth, containing a "heavy" isotope of nitrogen, 15N. After many generations growing in the 15 N medium, the nitrogenous bases of the bacteria's DNA were all labeled with heavy 15N. Then, the bacteria were switched to medium containing a "light" 14N isotope and allowed to grow for several generations. DNA made after the switch would have to be made up of 14N as this would have been the only nitrogen available for DNA synthesis. |
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