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What did Meselson and Stahl observe when They cultured E. coli in a medium containing `""^15Nh_4CL` for a few generations and centrifuged the content? they transferred one such bacterium to the normal medium of `NH_4Cl` and cultured for 2 genretion ? What did Meselson and Stahl conclude from this experiment? Explain With the help of diagram Which is the first geretic material? Give reasons in support of your answer. |
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Answer» Meselson and Stahl obsered that in the E. coli bacterium the DNA becomes completely labelled with `N^15` medium by centrifugation for few genretion ·After two genretion density changed and showed equal amount of light DNA(`N^14`) and dark hybrid DNA `(N^14-N^15)`. They concluded that DNA replicates semi-conservately.[For Figure See Q. 30. Set-I. Outside Delhi, 2008]. .RNA is the first genetic material. RNA is highly reactive, and acts as a catalyst as well as genetic material. Essential life processes such as metabolism, translation and splicing evolved around RNA. |
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