Molecular Basis of Inheritance Question 111
111. Escherichia coli fully labelled with ${ }^{15} N$ is allowed to grow in ${ }^{14} N$ medium. The two strands of DNA molecule of the first generation bacteria have
[1992]
(a) different density and do not resemble parent DNA
(b) different density but resemble parent DNA
(c) same density and resemble parent DNA
(d) same density but do not resemble parent DNA
Show Answer
Answer : c
Hints & Solution
(c) After one generation in ${ }^{14} N$ medium DNA of bacteria settled at a level intermediate between heavy and light bands due to semi conservative DNA replication.
