Final answer:
Gel electrophoresis is a molecular biology technique used for separating DNA, RNA, or proteins based on size, where molecules migrate through an agarose or polyacrylamide gel matrix under an electric field and can be visualized with specific stains.
Step-by-step explanation:
Gel electrophoresis is a pivotal technique in molecular biology used to separate DNA, RNA, or protein molecules based on their size. The separation occurs as these negatively charged molecules are forced to migrate through a gel matrix due to the application of an electric current. Typically, the gel is composed of agarose or polyacrylamide and acts as a sieve, allowing smaller molecules to pass through more quickly than larger ones.
The process starts with preparing the gel and loading the molecules into wells in the gel. An electric field is applied across the gel, causing the negatively charged molecules to move towards the positive electrode. Through this migration, molecules are sorted by size; shorter sequences travel farthest, creating a pattern of bands that can be visualized and compared against a molecular weight standard, or ladder.
The visualization of the separated molecules is commonly achieved by staining the gel with substances like ethidium bromide, which binds to nucleic acids and fluoresces under UV light. This critical step allows scientists to see the migration pattern of the DNA fragments, with distinctive bands representing different fragment sizes or, in some cases, resulting in a smear when a large number of fragments are present.