The experiment of Matthew Meselson and Franklin Stahl showed the mechanism of DNA replication by growing a culture of E. coli for several generations. They first grew the microorganisms in a medium with 15N-labeled nucleotide precursors. They then transferred it to a medium with 14N precursors.
Watson and Crick, the discoverers of DNA structure, proposed a semiconservative model of replication. Meselson and Stahl carried out experiments to test this by labeling DNA with isotopes of nitrogen 14N and 15N.
Labeled DNA were isolated from bacteria and centrifuged.
Match the experimental condition with the result observed in the centrifuge tube.
DNA isolated from E. coli grown in 15N medium
DNA isolated from E. coli grown in 14N medium
DNA isolated from E. coli grown first in 15N medium then transferred to 14N medium for one generation.
A. single upper band of DNA
B. intermediate band of DNA
C. single lower band of DNA
D. two bands of DNA (upper and lower)
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