Question

The DNA fragments separated on an agarose gel can be visualized after staining with:
A. Ethidium bromide
B. Bromophenol Blue
C. Acetocarmine
D. Aniline Blue

Answer 1

When an electric field gets applied across the two electrodes which are totally submerged in a colloidal solution, the particles (or colloidal) often tend to move towards the one or the other electrode.

Complete answer:
Gel electrophoresis is defined as a process of which is used to separate the DNA fragments that have been digested by the restriction enzymes(or endonucleases that can cut the DNA at the specific sites which are known as recognition sites).

Principle: DNA being negatively charged , gets often attracted towards the anode when an electric field is flowed across it. The lighter fragments of the DNA, then move faster & the heavier fragments at a slower, hence they often get separated. The separation of the fragments can be easily viewed by staining it with the ethidium bromide & then exposing it to UVrays and this way we can generally see the extent of the separation. The desired DNA fragments can then be cut from the gel & extracted from the gel piece by the elution.

Hence, the correct answer is option (A).

Additional information:
The two application of gel electrophoresis in biotechnology are as following:
• Gel electrophoresis often helps in the identification of the particular segment of the DNA & thus usually helping in the studying of that DNA fragment. It also helps normally, in checking the quality of the DNA along with the quantity it has, by checking the size of the DNA band on the gel.
• It plays a very crucial role in separating the molecules like DNA, RNA and the proteins. It has a very crucial role in criminal case testing of the DNA and to diagnose particular genetic diseases, if needed.

Note: Gel electrophoresis is a very powerful technique which can help to purify and then separate molecules like the DNA contained in a mixture and to estimate their approximate size. The separation of the fragments is quite an important step of the recombinant DNA tech. The fragments of the DNA separated, is analysed for the desired gene which can then be used to construct the recombinant DNA. Thus gel electrophoresis often helps us to separate the desired gene or the fragments of the DNA from the mixture or the unwanted DNA which is used then to construct the recombinant DNA.