Final answer:
In DNA gel electrophoresis, DNA travels towards the positive electrode due to its negative charge. Smaller DNA fragments move faster and travel farther in the gel, while larger fragments travel a shorter distance. The separated DNA is visualized using a DNA-specific dye.
Step-by-step explanation:
In DNA gel electrophoresis, your DNA should travel towards the positive electrode. This movement is due to the net negative charge of the DNA, which is attributed to the phosphate groups in its backbone.
Factors like the pore size of the gel and the molecular weight of the DNA fragments play a significant role in the separation process. Smaller fragments with lower molecular weight move faster and therefore travel farther through the gel, whereas larger fragments with higher molecular weight move more slowly and travel a shorter distance. To visualize these separated DNA fragments, a DNA-specific dye like ethidium bromide is used.
Advanced techniques such as pulsed-field gel electrophoresis (PFGE) can be used for separating very large DNA fragments. In PFGE, the orientation of the electric field is periodically altered, which helps to distinguish between large DNA molecules that may travel together under standard conditions.