Final answer:
Gel electrophoresis is the correct answer as it is a laboratory method used to separate DNA, RNA, or proteins according to their size and charge with smaller fragments moving faster towards the positive electrode.
Step-by-step explanation:
During gel electrophoresis, separation of molecules based on size and charge occurs. DNA is negatively charged due to the phosphate groups, and during gel electrophoresis, this property causes DNA molecules to migrate from the negative end to the positive end of the gel matrix. Pore size within the gel plays a critical role as shorter DNA chains migrate at a faster rate through the gel than longer ones.
This is because the porous gel matrix acts as a sieve, where the smaller the fragments, the less they are impeded by the gel’s matrix structure, allowing them to move more quickly towards the positive electrode. After the separation is completed, DNA fragments are commonly visualized through staining with a fluorescent dye like ethidium bromide, which binds to DNA and is visualized under ultraviolet light. This results in the appearance of bands on the gel, which correspond to DNA molecules of different lengths.