Semiconservative replication of $DNA$ was first demonstrated in
Escherichia coli
Streptococcus pneumoniae
Salmonella typhimurium
Drosophila melanogaster.
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 $15\,N$ ?
Replication of $DNA$ is in
In which type of $DNA$ replication of the two newly formed molecules one is purely a new one and the other one is old
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
In Meselson and Stahl's experiments, heavy $DNA$ was distinguished from normal $DNA$ by centrifugation in