a) How do DNA fragments migrate and resolve in a Gel electrophoresis?
b) How lane one is different from lane 2,3 and 4 in the GEL electrophoresis set up?
c) How pure DNA fragments are made observable in the visible light?

Explanation

(a) The DNA fragment resolve according to their size through sieving effect provided by the agarose gel. Hence, the smaller the fragment size, the farther it moves.
(b) The given agarose gel electrophoresis shows migration of undigested DNA fragments in lane 1 and digested set of DNA fragment in lane 2 to 4.
(c) The separated DNA fragment can be visualized only after staining the DNA with a compound known as ethidium bromide followed by exposure to UV radiation.