Gel Electrophoresis
DNA is a double stranded helical polymer. It contains the genetic information that governs the behaviour and structure of an organism.
The backbone of a single DNA strand consists of a phosphate sugar backbone, as shown on the right. This has a negative charge which is exploited in gel electrophoresis.
The DNA is chopped up into small strands and loaded onto an agarose gel. This is a thick gel and impedes the movement of molecules according to their size. When an elctric field is applied the negative charged strands of DNA move towards the positive terminal, as shown on the right.
The larger DNA strands, with a heavier molecular mass, move slowly through the gel while the smaller molecules move with little resistance.
Exercises