Question

The following is the test-tube contaning DNA from Meeselson and Stahl experiment. Find out what a,b and c could be:

Answer 1

There were three basic models for DNA replication that had been proposed by the scientific community after the discovery of DNA's structure. These models are illustrated in the diagram below:

Semi-conservative replication. In this model, the two strands of DNA unwind from each other, and each acts as a template for synthesis of a new, complementary strand. This results in two DNA molecules with one original strand and one new strand.

Conservative replication. In this model, DNA replication results in one molecule that consists of both original DNA strands (identical to the original DNA molecule) and another molecule that consists of two new strands (with exactly the same sequences as the original molecule).

Dispersive replication. In the dispersive model, DNA replication results in two DNA molecules that are mixtures, or “hybrids,” of parental and daughter DNA. In this model, each individual strand is a patchwork of original and new DNA.