GEL ELECTROPHORESIS

GEL ELECTROPHORESIS

DEFINITION:
The techniques which is used for the separation of molecules on the bases of their size and charge in gel under the influence of electric field is called gel electrophoresis.

PROCEDURE:
In this techniques agarose gel act as molecular sieve and separate the molecules on the basis of their size and surface charge. The gel is poured into the plastic plates to form a viscous slab. Two ends of the slab are suspended in salt solution which are connected b electrodes to a power source. When voltage is applied the molecules start moving through the gel. Negatively charged molecule moves towards positive pole and positively charged molecules moves towards the negative pole.

TYPES OF ELECTROPHORESIS

*) ANAPHORESIS: (Separation of histone)

*) CATAPHORESIS: (Separation of DNA/RNA)

FACTORS AFFECTING THE SPEED OF MOLECULES:
Two factors affect the speed, with which charged molecule move towards an electrode.
a) The amount of charge (greater charge, faster movement and vice versa)
b) The size of molecule (smaller molecules, faster movement and vice versa)
c) Shape of DNA
d) Concentration of gel.

TYPES OF GEL:
Different gel types and conditions are used for different molecules and types of applications.

AGAROSE:
A common gel for separating large DNA fragments is made of agarose

POLYACRYLAMIDE:
For separation of small DNA fragments polyacrylamide gel is used.

APPLICATION:
Gel electrophoresis separates macro molecules such as Nucleic Acid and proteins on the basis of their rate of movement through an agarose gel in an electric field. The distance a DNA molecule travels is inversely proportional to its length or size.