Meselson and Stahl

Question 1

semiconservative replication def

Answer 1

saving half (of the original) when replicating

Question 2

Explain Meselson and Stahl’s experimental setup and what was concluded from the results

Answer 2

They cultured E. coli in a medium containing nucleotides labeled with a heavy isotope of nitrogen. They transferred the bacteria to a medium with only a lighter isotope of nitrogen. Samples were each time after DNA was replicated. Three models were made with the predicted results, conservative, semiconservative, and dispersive. The conservative would work because there was supposed to be a mixture of the two nitrogens but there wasn’t, and dispersive was also ruled out because there wasn’t the same banding pattern. So semiconservative replication is correct.

Question 3

True or False:
in a conservative model, the original DNA strand is not split apart at all

Answer 3

true

Question 4

True or False:
Meselson and Stahl determined that dispersive replication was what was actually happened

Answer 4

false; it was semiconservative replication