This is a technique used to separate DNA fragments according to their size.
DNA samples are loaded into wells (indentations) at one end of a gel, and an electric current is applied to pull them through the gel.
DNA fragments are negatively charged, so they move towards the positive electrode. Because all DNA fragments have the same amount of charge per mass, small fragments move through the gel faster than large ones.
When a gel is stained with a DNA-binding dye, the DNA fragments can be seen as bands, each representing a group of same-sized DNA fragments.
Suppose you have just done a PCR reaction making many copies of a target DNA region. Or perhaps you’ve done some DNA cloning trying to "paste" a gene into a circular DNA plasmid.
Now, you want to check and see whether your PCR worked, or whether your plasmid has the right gene in it. What technique can you use to visualize (directly observe) the fragments of DNA?
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In this procedure, macromolecules (DNA, RNA, Proteins) are moved through a matrix (agarose or acrylamide) based on their size and charge.
Gels for DNA separation are often made out of a polysaccharide called agarose, which comes as dry, powdered flakes. When the agarose is heated in a buffer (water with some salts in it) and allowed to cool, it will form a solid, slightly squishy gel. At the molecular level, the gel is a matrix of agarose molecules that are held together by hydrogen bonds and form tiny