Agarose

Agarose

Agarose gel in borate buffer

Structure of agarose polymer

Agarose gel under UV light

Agarose is a polysaccharide polymer material, generally extracted from certain red seaweed. It is a linear polymer made up of repeating units of agarobiose, which is a disaccharide made up of D-galactose and 3,6-anhydro-L-galactopyranose. Agarose is widely used in molecular biology for the separation of large molecules, especially DNA, by gel electrophoresis.

Structure

Agarose is a linear polymer with a molecular weight of about 120,000 daltons. The basic structure of agarose consists of alternating D-galactose and 3,6-anhydro-L-galactopyranose units. These units form a double helix, which aggregates into a three-dimensional network that can trap water molecules, forming a gel.

Properties

Agarose gels are porous and can be used to separate molecules based on size. The gel's pore size can be controlled by adjusting the concentration of agarose in the gel. Higher concentrations of agarose result in smaller pore sizes, which are suitable for separating smaller molecules.

Applications

Agarose is primarily used in gel electrophoresis for the separation of nucleic acids. It is also used in size exclusion chromatography and as a medium for immunodiffusion and immunoelectrophoresis.

Gel Electrophoresis

In gel electrophoresis, agarose gels are used to separate DNA or RNA molecules by size. The nucleic acids are loaded into wells in the gel and an electric field is applied. The negatively charged DNA or RNA molecules migrate towards the positive electrode, with smaller molecules moving faster through the gel matrix.

Size Exclusion Chromatography

Size exclusion chromatography apparatus

Agarose is also used in size exclusion chromatography, where it serves as a stationary phase. The gel matrix allows for the separation of molecules based on size, with larger molecules eluting first.

Preparation

Agarose gels are prepared by dissolving agarose powder in a buffer solution, heating the mixture until the agarose is completely dissolved, and then allowing it to cool and solidify in a casting tray. The concentration of agarose in the gel can be varied to suit different experimental needs.

Related pages

• Gel electrophoresis
• Polyacrylamide gel electrophoresis
• Agar
• Chromatography

Gallery

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  Agarose gel in borate buffer
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  Structure of agarose polymer
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  Agarose gel under UV light
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  Size exclusion chromatography apparatus

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  Two percent agarose gel in borate buffer
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  Agarose polymer structure
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  Agarose gel under UV light
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  Size exclusion chromatography apparatus