Wize AP Biology Textbook > Biotechnology
Agarose Gel Electrophoresis
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(Agarose) Gel Electrophoresis
This technique is often coupled with PCR to check whether the expected nucleotide fragment was generated during PCR. The molecules of DNA are mobilized through a layer of gel (made of agarose) by an electric current, the molecules separate according to size.
- RNA/DNA are negatively charged molecules.
- The nucleic acids are placed in a small hole called a well on an agarose gel.
- An electrical current is then applied to the gel.
- The negatively charged nucleic acids move through the gel towards the positive end.
- The gel acts like a matrix.
- Smaller sized nucleic acids move more quickly through the matrix, while larger nucleic acids move more slowly.
- This separates nucleic acids based on size.
- A DNA ladder (standard sample) is usually used so that the size of the DNA molecules produced by the PCR can be measured/compared.
- Below is how a 600 base pair (bp) fragment produced by PCR would look like on gel electrophoresis.
