Question

After several generations of labeling cells in 15N media, the cells are switched to 14N media for one generation. The DNA extracted after one generation in 14N media was centrifuged in a cesium gradient. The DNA formed a single band with a density somewhere between DNA grown in 15N media and DNA grown in 14N media. This data is consistent with which replication model:

A) conservative replication only
B) conservative and dispersive replication
C) semiconservative replication only
D) dispersive replication only
E) semiconservative and dispersive replication

Answer 1

Answer: Option E

Step-by-step explanation:

The experiment that was conducted for the labeling of cells in 15 N media and then for a generation in 14N media shows two replication model

One is the semi-conservative model in which a single strand of the DNA acts as the template strand to make new complementary copies of DNA.

The other model is the dispersive replication which shows the hybrid of two DNA. The parental and the daughter cells are both shown in the newly synthesized DNA.

Hence, the correct answer is Option D