What is gel electrophoresis and how does it work?

Gel electrophoresis is a technique for separating DNA, RNA, or proteins based on size and charge by applying an electric field across a gel matrix (agarose or polyacrylamide). Nucleic acids, being negatively charged due to phosphate groups, migrate toward the positive electrode (anode). Smaller molecules move faster through the gel pores, resulting in size-based separation. DNA is visualized using fluorescent dyes like ethidium bromide or SYBR Safe, and size is determined by comparison to molecular weight markers.