Question

Which one of the following statements is wrong with respect to the separation of DNA fragments on electrophoresis?
A. The DNA fragments move towards anode under the electric field through the matrix.
B. The commonly used matrix is agarose gel.
C. The DNA fragments resolve according to their size.
D. None of the above.

Answer 1

Electrophoresis means ‘to bear electrons’ in general. It is a laboratory technique used to separate DNA, RNA or protein molecules based on their size and electrical charge. These molecules are subjected to a matrix for the process to occur.

Complete step by step answer: Electrophoresis is the process used to separate macromolecules in a fluid or gel, based on their charge, binding affinity and size, under an electric field. This has a wide application in separating and analysing biomolecules such as proteins, plasmids, RNA, DNA, nucleic acids, etc. The advantage is that the gel is easily poured and does not denature the sample. These samples after use can also be recovered. The disadvantage is that the gel can melt during the process of electrophoresis. Agarose gel electrophoresis is mainly used for the separation of DNA molecules on the agarose gel matrix. As the DNA is a negatively charged molecule, it is loaded over the gel matrix. Based on mass and the charge on the DNA, the loaded sample is induced by the electric field which leads to the separation process. Based on mass, the DNA gets aligned as they all are negatively charged. The smaller DNA molecules get faster on the top with having the larger ones in the bottom.
So, the correct answer is option D.

Note: For calculating the electrophoresis, the following formula is used;
${\mu _e} = \dfrac{v}{E}$
Where, ${\mu _e}$ represents the electrophoresis
v represents the drift velocity
E represents the electric field strength