Gel Electrophoresis

Overview

• Gel electrophoresis is a technique used to separate biological molecules such as DNA, RNA, and proteins based on charge and size.
• Utilizes a polymer matrix (gel) and an electrical current to sort and visualize molecules.
• Separated biomolecules are revealed as bands on the gel using various staining or visualization methods.

Process

1. Sample Preparation

   • Samples are pipetted into wells in the gel.
   • Wells are located near the negative electrode for negatively charged molecules like DNA.
   • Molecules migrate toward the positive electrode when current is applied.

2. Polymer Gel Setup

   • The gel is made of a polymer; agarose is commonly used for DNA/RNA.
   • Agarose forms a porous matrix with holes, allowing molecules to pass through.
   • Concentration of agarose influences pore size, affecting molecule movement.

3. Molecule Separation

   • Molecules of different sizes/shapes travel at different speeds, ending at various distances from the well.
   • Molecules of the same size/shape travel similarly through the gel.

Visualization

• Biomolecules are typically not visible, requiring a visualization method after electrophoresis.
• Loading dye: Used to track electrophoresis progression but does not indicate molecule position.
• Fluorescent dyes: Bind to biomolecules and fluoresce under certain light wavelengths. Can be used before or after electrophoresis.

Figures

• Figure 1: Shows samples being loaded into wells using a micropipette with a buffer covering the gel.
• Figure 2: Illustrates the agarose matrix with varying hole sizes.
• Figure 3: Demonstrates biomolecule separation by size and charge.
• Figure 4: Displays DNA bands visualized with ethidium bromide dye.

Additional Information

• Created with support from the Amgen Foundation.