How are DNA segments seprated and observed through gel electophoreses.

How can DNA segment, separated by gel electrophoresis be visualised and isolated ?

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?

DNA segment cleaved by EcoRI is

What is the criterion for DNA fragments movement on agarose gel during gel electrophoresis ?

What is the criterion for DNA fragment movement on agarose gel during gel electrophoesis

Why do DNA fragments move towards the anode during gel electrophoresis ?