Question

In the meselson-stahl experiment, cells were grown for one generation in growth medium containing a relatively heavy nitrogen isotope, then transferred to new medium containing a lighter nitrogen isotope. after one round of dna replication, what was true of the dna in the cells?

Answer 1

Out of the following give choices;

a. All DNA strands contained only the heavy nitrogen isotope.

b. Half of the DNA strands contained only the light nitrogen isotope.

c. All DNA strands contained both heavy and light nitrogen isotopes.

d. All DNA strands contained only the lighter nitrogen isotope.

The answer is b. Meselson–Stahl experiment demonstrated the semi-conservative model of DNA replication. When DNA is replicated, one strand of the new double helix strand is the parent's strand while the other is the newly synthesized one. This made the semiconservative model stand out over the other two, dispersive and conservative models.