Final answer:
Gel electrophoresis is a method for sorting DNA fragments based on size using key components and resulting in bands allowing for size estimation alongside a DNA ladder.
Step-by-step explanation:
Gel electrophoresis is a laboratory method used to separate mixtures of DNA, RNA, or proteins according to molecular size. The components necessary for successful DNA electrophoresis include an agarose gel to act as the medium, a DNA sample, a buffer solution that maintains the pH, an electric power supply, and DNA markers or a ladder for size comparison.
During the process, DNA fragments are loaded into wells in the gel, and an electric current is applied. The negatively charged DNA fragments move towards the positively charged electrode at different rates, depending on their size—smaller fragments move faster and travel further through the gel matrix. After sufficient time, the fragments form distinct bands that are visualized using a DNA-specific dye under UV light. This allows scientists to judge the size of plasmid DNA by comparing it to the DNA ladder with known sizes, ranging from 1000 to 10,000 base pairs (bp).