Agarose Gel Electrophoresis of DNA Lab Report Example | Topics and Well Written Essays - 1250 words

Agarose Gel Electrophoresis of DNA - Lab Report Example DNA is the double stranded helical structure which carries the genetic information. The study of the DNA molecule will give us the details about life. DNA molecules can be extracted from the cell using the extraction techniques and they are then quantified using the agarose gel electrophoresis. The DNA fragment is separated in the Agarose based on the pore size (that is the concentration of the agarose), the voltage applied, the molecular size of the DNA molecule and the conformation of the DNA. The smaller molecules a move downwards in the gel faster than the larger molecules and the separation occurs based on the size of the DNA. If high voltage is applied, then the migration will be faster but the separation of the DNA fragments will not be clear. (Westermeier 2006). So, 110 volts for 30- 45 minutes is usually applied for the separation of the DNA fragments in the gel. The agarose gel electrophoresis of the DNA molecule showed distinct bands in the lanes 4,5 and 6 indicating that only a single DNA is present in the sample. Introduction: Doeoxy ribo nucleic acid (DNA) is a polymer consisting of base, sugar and a phosphate bond. The sugar is always deoxy- ribose in case of DNA and the base will be a purine or pyrimidine molecule: Adenine, Guanine, Cytosine or Thymine. Phosphate molecule connects the two nucleosides. DNA is a covalently linked structure which is helical in shape. DNA is a double helical structure held together by the hydrogen bonds. DNA carries the genetic information. ... Since DNA are acidic in nature, they migrate towards the positive pole when exposed to an electric field. The pore sixe of agarose sieve is determined by the concentration of agarose. Agarose gels are made with a concentration varying from 0.7- 1.5%. DNA in a neutral solution is negatively charged. (Williamson and Campbell 1997). So if an electric field is applied to the DNA, it will move towards the anode pole from the cathode pole. Based on the fragment size, the rate of migration will be inversely proportional to the fragment size. The smaller fragments will move faster than the larger ones and the distance moved by the fragments are measured by using the molecular marker. Molecular marker is the standard DNA fragment sizes which act as the standards to measure the molecular weight of the DNA fragments. Thus by providing constant voltage into the agarose gel, we are able to separate the DNA fragments based on their molecular weight. (Westermeier 2006). Agarose Gel Electrophoresis of DNA is a very simple and reproducible technique. The mobility of the DNA molecule in neutral solution was independent of the size of the fragment but varied with the ionic strength .The DNA fragments of up to 40 kilo base pair can be separated using agarose gel electrophoresis. (Williamson and Campbell 1997). The DNA fragments get separated based on molecular size, the current applied, concentration of Agarose and the conformation of the DNA. Agarose is a copolymer containing 1,3-linked ?-D-galactose and 1,4-linked 3,6- anhydro-?-L-galactose linked together by the junction zones and joined by the hydrogen bonds. (Stellwagen 2009). A standard ladder is used to identify the size of the fragments. In