The Messelson and Stahl experiment showed that DNA replication is
Show Hint
- dispersive
- conservative
- semi-conservative
- distributive
The Correct Option is C
Solution and Explanation
Step 1: Concept
The Meselson-Stahl experiment was designed to distinguish between three hypothesized models of DNA replication: conservative, semi-conservative, and dispersive.
Step 2: Meaning
Semi-conservative replication implies that each daughter DNA molecule contains one original parent strand and one newly synthesized strand.
Step 3: Analysis
By growing E. coli in a medium containing heavy nitrogen ($^{15}N$) and then switching to light nitrogen ($^{14}N$), the researchers used density gradient centrifugation to observe the density of the resulting DNA. After one generation, the DNA was of intermediate density, ruling out the conservative model. After two generations, both intermediate and light DNA were present, which specifically supported the semi-conservative model.
Step 4: Conclusion
The experimental evidence conclusively proved that DNA replicates semi-conservatively. Final Answer: (C)
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