Biology - Molecular Basis of Inheritance Question with Solution | TestHub

Meselson and Stahl used heavy isotope ${}^{15}\text{N}$ to label DNA and separated the heavy DNA from normal DNA using Cesium Chloride ($\text{CsCl}$) density gradient centrifugation.

The density of 6M $\text{CsCl}$ is approximately $1.7{\text{ g/cm}}^3$, which is almost equal to the buoyant density of DNA.

During centrifugation, a density gradient is established, and DNA molecules move to the position in the gradient where the density of the $\text{CsCl}$ solution exactly matches their own density. Therefore, 6M $\text{CsCl}$ was chosen because its density gradient value is almost equal to the density gradient value of ${}^{15}\text{N}$ DNA.

Answer: almost equal to