Final answer:
PAGE is a method for separating proteins or DNA fragments using a polyacrylamide gel matrix. It can separate molecules based on size when an electric current is applied, and it can use SDS for proteins or urea for RNA to ensure separation by molecular weight. Afterward, the molecules are visualized using appropriate stains.
Step-by-step explanation:
Polyacrylamide gel electrophoresis (PAGE) is a technique used for separating proteins or DNA fragments based on their size and charge. In PAGE, samples are loaded onto a gel matrix composed of polyacrylamide, which is finer than agarose gel, typically used in standard gel electrophoresis. The setup includes a vertical gel apparatus where the gel acts as a sieve, allowing smaller molecules to travel faster than larger ones when an electric current is applied. Proteins can be separated based on their net charges or by using sodium dodecyl sulfate (SDS), which denatures the proteins and imparts them with a uniform negative charge, allowing for separation based on size.
For separating RNA molecules, denaturing PAGE uses a similar approach with the addition of urea that denatures the RNA, ensuring that the migration through the gel is influenced only by the RNA's molecular weight. After electrophoresis, proteins or nucleic acids are visualized using staining methods such as Coomassie blue, silver stain, or EtBr for nucleic acids.