Do you know what agarosa is? Surely you will not be familiar with terms like this if you often visit the laboratory. Well, agarosa is a gel used in biochemistry and biotechnology for electrophoresis and special size chromatography which is a method of sorting large molecules by size and electric charge.

This sorting process uses agarosa to separate and analyze proteins and DNA. Whereas the agarosa material comes from various types of seaweed and is usually found in laboratories in powder form. Now to make a suitable medium for a particular test first the powder is dissolved into the water at the required concentration (right) then boiled and then allowed to cool until it becomes a gel that is ready for use.

Agarosa gel electrophoresis is a method of separating DNA and RNA molecules according to charge, size and shape. This technique is simple, quickly formed, and can separate the mixture of pieces of DNA according to their size accurately, compared to the centrifugation gradient density. When an electric current is applied to the gel, the negatively charged molecule will move towards the positive electrode and the positively charged molecule will go to the negatively charged electrode. The factors that cause the failure of agarosa gel electrophoresis are because the cell has not been fully lysis, DNA has not yet come out of the cell, and DNA has degraded (mechanical pressure).

The agarosa gel electrophoresis method is based on the movement of charged molecules in a stable matrix buffer medium under the influence of an electric field. The media commonly used is agarosa gel or polyacrylamide. Agarosa gel electrophoresis is used to separate DNA fragments larger than 100 bp and run horizontally, whereas polyacrylamide electrophoresis can separate 1 bp and run vertically. Polyacrylamide electrophoresis is usually used to determine the DNA sequence (sequencing). Organic molecules that can be electrophoresed include DNA, RNA, and protein. The positively charged molecules will move towards the negative electrode, while the negatively charged molecules will move to the positive electrode through the electrophoretic gel. The location of DNA fragments formed like bands on electrophoresis can be specifically observed using dyes. The dye used is ethidium bromide which can be inserted between bases in DNA. Gels that are given ethidium bromide and irradiated with UV will show the location of DNA as a red-orange strand. Ethidium bromide is a carcinogenic compound so in carrying out experiments that use ethidium bromide must use gloves.