Practice question

Zone electrophoresis separates molecules into discrete zones or bands on a stabilizing support to minimize convection and diffusion. Early methods employed filter paper or cellulose acetate strips saturated with buffer, providing a solid anticonvective medium. Samples migrate as discrete zones under applied voltage. Glass and plastic are not porous supports for zone stabilization. Modern zone electrophoresis uses agarose or polyacrylamide gels as improved supports, but historically and categorically, paper represents the classic support matrix distinguishing zone electrophoresis from moving-boundary or free-flow electrophoresis.