Practice question

CsCl density gradient centrifugation uniquely separates DNA species based on conformation and buoyant density in an isopycnic gradient. Supercoiled, nicked, and linear DNA differ in capacity to intercalate EtBr, resulting in distinct buoyant densities and band positions. Silica columns and magnetic beads purify by adsorption based on chemical interaction with matrix, not conformation. GITC lysis denatures proteins for extraction but does not resolve topology. Therefore only CsCl centrifugation discriminates DNA forms by supercoiling, linking conformational state to measurable density differences for high-resolution purification of plasmids.