1. Gel Electrophoresis

6. The term electrophoresis describes the migration of charged particle under the influence of an electric field.
Electro refers to the energy of electricity.
Phoresis means "to carry across."

7. Molecules are forced across a span of gel, motivated by an electrical current.
Activated electrodes at either end of the gel provide the driving force. A molecule's properties determine how rapidly an electric field can move the molecule through a gelatinous medium.

8. How does this technique work?
It is used for the separation of nucleic acids (DNA) and proteins.
Separation of large (macro) molecules depends upon two forces: charge and mass.
When a biological sample, such as proteins or DNA, is mixed in a buffer solution and applied to a gel, these two forces act together.

9. The electrical current from one electrode repels the molecules while the other electrode simultaneously attracts the molecules.
The frictional force of the gel material acts as a "molecular sieve," separating the molecules by size.
After staining, the separated macromolecules in each lane can be seen in a series of bands spread from one end of the gel to the other.

10. What is in a gel?
There are two basic types of materials used to make gels: agarose and polyacrylamide.
Agarose is from sea weed. It is very fragile and easily destroyed by handling.
Agarose gels have very large "pore" size
The bands formed in the agarose gels are fuzzy and spread far apart. This is a result of pore size and it cannot be controlled.

11. Analogy: A gel can be compared to a sponge.
Think of the DNA moving through the holes of a sponge.

13. Electrophoresis animation

14. **start notes here Gel electrophoresis
The process by which scientists can sort pieces of DNA cut with restriction enzymes by size.

15. An agarose or polyacrylamide gel is loaded with the DNA fragments and an electric current is passed through the gel.
The buffer is a medium that allows the electric current to carry the negatively chanrged DNA through the gel.

16. Since DNA is negatively charged, it will migrate towards the positive pole.
The DNA will not migrate at the same rate, however.
Larger pieces of DNA collide with the gel matrix more often and are slowed down, while smaller pieces of DNA move through more quickly.

18. Applications DNA Fingerprinting The Human Genome Project
Forensics
Paternity Testing
The Human Genome Project
DNA Recombinant Technology
(*click on DNA Fingerprinting)

19. Virtual Gel Electrophoresis