Meselson and Stahl QuestionsWatch
I answered it wrong apparently
"batch c shows the results after 3 generations, according to the semi-conservative model of DNA replication this means there's been a 50% split as half is now heavy nitrogen and half is lighter nitrogen. After the first generation, it's 100% heavy, then in the second, the introduction of lighter nitrogen means it's now got one strand of lighter nitrogen and one heavy. so has a medium-density, whereas in the 3rd gen its been split completely 50% so half the strands are heavy and half are light, hence the different band positionings"
My teachers comment was that I didnt even answer the question. I'm quite confused as to what I was meant to have written - need to rewrite the real answer to give in. help??
This result proves that DNA replication must be semi-conservative, as the N14 strand must act as a template, otherwise the light molecule wouldn’t exist. We’ve already seen that the N15 strand acts as a template (hence the existence of the intermediate molecule, which has one strand of light and one of heavy DNA). Because both strands act as a template and the new molecule consists of one strand of original, and one strand of new DNA, DNA replication must be semi conservative.