Question

Why is cesium chloride used as density gradient in meselson -stahl experiment ?

Answer 1

Under high centrifugal force, a solution of cesium chloride (CsCl) molecules will dissociate.The heavy Cs⁺atoms will be forced away from the center towards the outer end of the tube, but will at the same time diffuseback towards the top of the tube, thus forming a shallow density gradient. DNA molecules placed in this gradient will migrate to the point where they have the same density as the gradient (the neutral buoyancy or isopycnic point). The gradient is sufficient to separate types of DNA with slight differences in density due to differing [G+C] content, or physical form (e.g., linear versus circular molecules).