Final answer:
Agarose gel electrophoresis is a technique that separates DNA or RNA fragments by size, with smaller fragments traveling faster through the gel matrix. The technique exploits the negative charge of nucleic acids to facilitate their migration toward the positive electrode, with separation occurring due to differences in fragment length.
Step-by-step explanation:
Agarose Gel Electrophoresis Separation Principle
Agarose gel electrophoresis is a technique used to separate DNA or RNA fragments by size. Nucleic acids, being negatively charged at neutral or basic pH, are pulled through the gel matrix from the negative electrode toward the positive electrode when an electric field is applied. As these charged molecules migrate, smaller fragments move faster and farther through the gel's pores compared to larger ones. This allows the separation of nucleic acid fragments according to their length. Agarose, a polysaccharide extracted from seaweed, forms a porous matrix and the concentration of agarose used affects the pore size of the gel, thus influencing the resolution of fragment separation. Molecular weight standards run alongside samples provide a size comparison which can be visualized after staining the DNA with specific dyes.
In summary, agarose gel electrophoresis separates nucleic acid fragments based on size, and not by density, shape, or sequence.