Question

Which among the following are components of the agarose gel electrophoresis apparatus?

• A. Buffer, icepack, chamber
• B. Nylon membrane, powerpack, electrophoresis tank
• C. Electrophoresis unit and power supply
• D. Power pack, nylon membrane, capillary tube

Answer 1

The correct option is C Electrophoresis unit and power supply

Agarose gel electrophoresis is a laboratory technique commonly used to separate charged particles (here DNA) of varying sizes in an agarose matrix under the influence of electric fields. The DNA molecules (negatively charged) travel different distances while migrating towards the positive terminal (anode) in an electric field. These can be viewed as bands after ethidium bromide staining and UV visualisation.

The agarose gel electrophoresis apparatus has the following components:

Gel casting tray: It is the tray where the gel is placed.

• The gel is composed of agarose dissolved in buffer solution (TAE or TBE) by heating followed by cooling.
• The gel contains wells which are formed using combs. The DNA sample is loaded inside sample wells.

Electrophoresis unit/tank: It is the plastic unit inside which the gel is placed.

• It has two terminals, anode (positive terminal) and cathode (negative terminal).
• It is flooded with a buffer solution to ensure proper ionic conduction.

Power supply: It provides the voltage to create an electric field of suitable strength. This exerts the driving force to carry the negatively charged DNA molecules towards the anode.