DNA has a negative charge...

Question

Given that DNA is negatively charged, which electrode would it migrate towards when subjected to an applied voltage? At which electrode should the wells of your agarose gel be placed and why?

Answer 1

Think about it like opposite charges attracting. DNA has a negative charge because of the phosphate groups in its backbone. So, when we apply an electrical current, the negatively charged DNA is attracted to the positive (+) electrode. That’s why we place the wells near the negative (–) electrode. When the current is turned on, the negative electrode helps push the DNA away from the wells, while the positive electrode attracts it. This causes the DNA to travel through the agarose gel toward the positive side.