Question

Given is the diagram of agarose gel kept under UV light.
What is the charge carried by DNA molecule and how does it help in its separation?

Answer 1

The DNA molecule is negatively charged, this charge allows the DNA molecule to travel under influence of an electric field. Hence, in an electrophoresis experiment, the negatively charged DNA moves toward the positive electrode, under the influence of electric field and it gets separated based on the size of fragments. The lighter and smaller fragments travel farthest.