Bacteria were grown in a medium containing heavy isotope of nitrogen `(N^(15))` for many generations and all their DNA contained many heavy nitrogen only. A bacterium of this type was transferred to nomal medium and allowed to duplicate . After two divisions of heavy DNA is likely to be that

Options

A. Only one daughter cell will have heavy DNA
B. Two daughter cells have normal DNA and other two have both normal and heavy DNA
C. All daughter cells have heavy DNA
D. Half daughter cells have DNA and other hald have normal DNA

Answer

b

Explanation

b) After two divisons, four bacterial cells are formed in which two daughter bacterial cells have normal DNA and other two have both normal and heavy DNA because DNA replicates by semiconservative method in bacteria.