Practice question

Standard phenol-chloroform DNA extraction involves phenol for protein denaturation, chloroform for phase separation and lipid removal, and isoamyl alcohol, added in a 25:24:1 ratio, as an antifoaming agent that stabilizes interphase and prevents bubbling. This mixture efficiently deproteinizes the lysate. SDS (sodium dodecyl sulfate), an anionic detergent used for membrane lysis and protein solubilization, is part of the initial lysis buffer but is not a component of the organic extraction mixture itself. It is removed prior to or during phenol treatment and precipitation steps.