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 normal medium and allowed to duplicate. After two divisions of heavy $DNA$ is likely to be that
Only one daughter cell will have heavy $DNA$
Two daughter cells have normal $DNA$ and other two have both normal and heavy $DNA$
All daughter cells have heavy $DNA$
Half daughter cells have heavy $DNA$ and other half have normal $DNA$
Ten E.coli cells with ${ }^{15} N$ - dsDNA are incubated in medium containing ${ }^{14} N$ nucleotide. After 60 minutes, how many E.coli cells will have DNA totally free from $15\,N$ ?
Choose the correct statement about the direction of $DNA$ strand
Self replication is occurred in
$DNA$ multiplication is called
A $DNA$ molecule in which both strands have radioactive thymidine is allowed to duplicate in an environment containing non-radioactive thymidine. What will be the correct number of $DNA$ molecules that contain some radioactive thymidine after three duplications