A NASA probe returned samples of rocks from the surface of Mars.From these rocks,a prokaryotic organism was isolated and remained viable under conditions similar to those of Mars.The organisms are capable of dividing to replicate themselves.In order to determine whether the DNA replication of these organisms was semiconservative,an experiment using N15/N14 (similar to that of Meselson and Stahl)was performed.If the method of DNA replication were conservative,after one generation one would expect to see A)all of the DNA in the heavy (N¹⁵)band. B)all of the DNA in the light (N¹⁴)band. C)all of the DNA at a point midway between the heavy and light bands. D)half of the DNA in the light band,the other half in the heavy band. E)None of these are correct.

Question

Quizplus · Accepted Answer

In conservative replication, the original DNA molecule is conserved, so after one generation, you would expect half of the DNA to remain in the heavy band (original N15 DNA) and the other half to be in the light band (new N14 DNA).

A NASA Probe Returned Samples of Rocks from the Surface