1. Technology that uses electricity to separate molecules in a gel slab
Gel Electrophoresis
Technology that uses electricity to separate molecules in a gel slab

2. Objectives To understand that molecules vary in size, shape and charge
To understand what gel electrophoresis is and how it is used to separate molecules based upon size and charge

3. Gel Electrophoresis
Acts as a molecular strainer, separating molecules based upon size, shape and charge
Smaller fragments travel faster and farther away from the wells than larger fragments
Molecule
Charge
Size
Behavior
DNA
Negative
500-25,000 bp
Towards positive, smaller moves faster
RNA
Less than 1000 bp

4. Larger
Fragments
Smaller
Fragments

5. Not Just DNA and RNA Molecule Charge Size Behavior Proteins
Positve, Negative or Neutral
1000 – 350,000 Daltons (amu)
Depends on charge and size, unless the protein is neutral
Carbohydrates
Most are neutral
Variable
Do not have net movement to either pole
Lipids

6. Components of Gel Electrophoresis Equipment

7. Agarose Gel Tray

8. Agarose Gel Tray

9. Gel Box with Buffer

10. Gel Box with Power Supply

11. More About Gel Electrophoresis
Two most common gels are agarose and polyacrylamide
Polyacrylamide gels – used to separate proteins and very small pieces of DNA and RNA
Buffer: stabilizes pH, maintains molecule shape, and conducts electricity

12. Polyacrylamide Gel Electrophoresis

13. Gel Stains
Ethidium Bromide (EtBr) – glows orange when exposed to UV light
Methylene Blue – dark blue bands
SYBR® Safe – glows green
GelGreen
GelRed