What role does the buffer play in gel electrophoresis and how does it impact the separation of DNA fragments?

The buffer in gel electrophoresis helps maintain a stable pH and conductivity, which is crucial for the movement of DNA fragments through the gel. It also provides ions that carry an electric current, allowing the DNA fragments to migrate towards the positive electrode. The buffer affects the separation of DNA fragments by influencing their mobility based on size and charge, resulting in the fragments being separated according to their molecular weight.