Question

In one or two sentences, summarize the technique of gel electrophoresis.
Last question in bio!!

Answer 1

This is a "little" bit more than two sentences:

In gel electrophoresis of DNA, DNA is separate of different lengths in a sample by using that DNA is negative charged. The negative charge resulting from the phosphate groups of each nucleotide of the DNA.

The gels used are solid and transparent. The gel is made from some specific molecules, such as agarose (a sugur).

The DNA sample was added to a well at the end of a gel, and is then connected to electrical potential difference. This creates a repulsive negative pole at the DNA sample, and an attractant, the positive pole on the other side of the gel (Figure 2). DNA will therefore now drag through the gel towards the positive side. The microscopic gaps in the gel makes the movement difficult for the DNA, the longer it is. Therefore the short DNA molecules run faster than through the longer.

After gel electrophoresis, the DNA will therefore be sorted in different bands by number of base pairs (all of which is 600 base pairs, is such right on top of each other).

Several drugs can make DNA visible to photography. Often used is ethidium bromide, which binds to the DNA, which then becomes visible in ultraviolet light, which is used for the photography of the finished gel. One can run several samples are side by side in a gel electrophoresis, where the outermost will typically be a label containing some already known lengths, to allow comparison with the samples.

Answer 2

There is also gel electrophoresis for proteins, but that is a bit different.