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Gel Electrophoresis

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What is Gel Electrophoresis?

Gel electrophoresis is a common technique that is used in different laboratories to properly separate charged molecules such as RNA, DNA, and proteins on the basis of their size. In the process, the charged molecules will be made to pass through a gel-like substance with electric current passing across it. The application of electric current occurs so that the ends of the gel are oppositely charged. 

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When the charged molecules move through the gel, the process is known as migration. These molecules properly migrate towards the end that has an opposite charge. Hence, the molecules that have a positive charge will be attracted to the end having the negative charge. With the process, it is easier to separate the smaller charged molecules. However, larger fragments can also be moved, albeit a little slower. In this article, students will learn what is gel electrophoresis and much more. 

Agarose Gel Electrophoresis

The use of agarose gel electrophoresis is done in order to separate the fragments of DNA. The process of restriction of endonuclease can be used for cutting the DNA into fragments. In this case, the various samples will create fragment lengths of variable types. The fragments are separated properly because DNA tends to have a negative charge due to the fact that a phosphate group is present. Agarose gel is used for the placement of the DNA samples and the calculation of the size is done for the process to complete. Different sequences with specific patterns can be identified with the help of this process. 

Polyacrylamide Gel Electrophoresis 

The applications of gel electrophoresis in order to separate the fragments of proteins uses Polyacrylamide Gel Electrophoresis. The proteins are basically folded to create different shapes that have negative as well as positive regions. The proteins should be properly treated using an anionic detergent so that a uniform negative charge can be imparted. The polyacrylamide gel is used for placing the protein samples and there is a comparison of the sizes that takes place. The proteins, once separated, are properly transported to a particular membrane. 

How Does the Process of Gel Electrophoresis Work? 

There are some important steps and processes that take place during the process of gel electrophoresis. With careful study of the gel electrophoresis principle, students will be able to understand the process better. 

  • Preparation Of The Gel 

The agarose gels are the main components of the process. These gels are commonly used in order to visualize all the DNA fragments. The amount of concentrated gel used in the process depends on the size that the DNA fragments have. With more concentration of agarose, the matrix will be denser. The separation of smaller fragments requires the concentration of agarose to be more in the process of agarose gel electrophoresis. In order to create the gel, experts mix the agarose powder with the electrophoresis buffer and melt the powder on high heat. 

  • Preparation of DNA 

A particular type of dye is added to the DNA sample before the entire process is begun. This increases the sample’s viscosity and hence it will not float out from the wells. This also helps in the process of proper migration. The marker of DNA, also called the DNA ladder, will be loaded right into the gel’s first well. These markers tend to have a proper length so that they can help in the approximation of the fragment size in the best way. Then the DNA samples will be transferred into the gel wells using a pipette. After that, the lid is properly placed on the tank to start the process. 

  • Fragment Separation 

Once the samples of the DNA have been transferred to the tank for the procedure of agarose gel electrophoresis to begin, the electrical current is turned on. After that, the charged particles in the DNA with a negative charge will move without any difficulty towards the gel’s positive side. It is easier to move the shorter DNA fragments and the process doesn’t even take a lot of time. The total distance that the DNA migrates can be easily identified by monitoring the entire process of migration. The buffer dye helps in that process by leaving a mark. The electric current should be kept running for a long enough time to make sure that all DNA fragments have moved far across so that the gel is able to properly separate them. 

  • Visualizing the Results 

After the migration process of the DNA fragments is complete, the electric current will be turned off. The gel is efficiently removed from the tank. In order to visualize the fragments of the DNA, the gel will be stained with a dye that is fluorescent in colour. This will bind itself to the DNA fragments. After binding, the fragments are put on the ultraviolet transilluminator that will allow the people to see some bright bands which are the stained DNA. 


The article above attempts to provide an explanation for the process of gel electrophoresis. Students can use this article and study the gel electrophoresis diagram to gain more information about the topic.

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FAQs on Gel Electrophoresis

1. What is gel electrophoresis?

The process of gel electrophoresis is used in the separation of charged molecules such as DNA, RNA, as well as proteins. The separation process is dependent on the size of the charged molecules. In this particular process, the molecules are made to pass through some gel-like substance that has an electric current passing through it. With the application of electric current in the process, both sides of the gel will have opposite charges. Hence, when the charged molecules pass through, the charges in these molecules will be attracted to the end of the gel that has an opposite charge. This process successfully separates the charged molecules. It is easier to separate the small fragments of charged molecules than the larger ones.

2. What is the main function of gel electrophoresis?

Gel electrophoresis is a widely used technique in laboratories for the separation of charged molecules. Mainly, gel electrophoresis is used for the separation of DNA and proteins. While the process of Agarose Gel Electrophoresis is used for the separation of DNA fragments, the Polyacrylamide Gel Electrophoresis is used for the separation of proteins. One of the most important things to keep in mind about the entire process of gel electrophoresis is that it uses a gel-like substance for the separation process and it is common for the process to use the Agarose gel. Electrical current is made to pass through the gel-like substance and hence the fragments are properly separated.

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