Read the following statements and find out the incorrect statements with reference to agarose gel electrophoresis.
(i) Now-a-days the most commonly used matrix is agarose which is a synthetic polymer extracted from sea weeds.
(ii) Larger the fragment size, the farther it moves.
(iii) We can not see pure DNA in UV light without staining.
(iv) DNA fragments separate (resolve) according to their size through sieving effect provided by the agarose gel
Read the following statements and find out the incorrect statements with reference to agarose gel electrophoresis.
(i) Now-a-days the most commonly used matrix is agarose which is a synthetic polymer extracted from sea weeds.
(ii) Larger the fragment size, the farther it moves.
(iii) We can not see pure DNA in UV light without staining.
(iv) DNA fragments separate (resolve) according to their size through sieving effect provided by the agarose gel
Agarose gel electrophoresis
Agarose gel electrophoresis is the technique involving the separation of molecules based on their size and charge.
Statement (i)
Agarose is a natural polymer extracted from sea weeds like the red algae Gelidium and Gracilaria. It is used in gel electrophoresis as a matrix.
Therefore given statement (i) is incorrect.
Statement (ii)
In agarose gel electrophoresis, the smaller the size of the molecule, the faster and farther it travels and the fragments are separated. Large size fragments cannot travel longer distances due to the resistance offered by the agarose gel.
Therefore given statement (ii) is incorrect.
Statement (iii)
To visualise DNA in the agarose gel, a positively charged dye ethidium bromide (EtBr) is added in the agarose gel or electrophoresis buffer.This dye intercalates itself into the DNA backbone and gives orange fluorescence upon exposure to the UV light.
Therefore given statement (iii) is correct.
Statement (iv)
DNA fragments are separated on the basis of their size due to the sieving effect of the agarose gel in gel electrophoresis.
Therefore the given statement (iv) in the question is correct.
Final answer
(d) i and ii
Agarose gel electrophoresis
Agarose gel electrophoresis is the technique involving the separation of molecules based on their size and charge.
Statement (i)
Agarose is a natural polymer extracted from sea weeds like the red algae Gelidium and Gracilaria. It is used in gel electrophoresis as a matrix.
Therefore given statement (i) is incorrect.
Statement (ii)
In agarose gel electrophoresis, the smaller the size of the molecule, the faster and farther it travels and the fragments are separated. Large size fragments cannot travel longer distances due to the resistance offered by the agarose gel.
Therefore given statement (ii) is incorrect.
Statement (iii)
To visualise DNA in the agarose gel, a positively charged dye ethidium bromide (EtBr) is added in the agarose gel or electrophoresis buffer.This dye intercalates itself into the DNA backbone and gives orange fluorescence upon exposure to the UV light.
Therefore given statement (iii) is correct.
Statement (iv)
DNA fragments are separated on the basis of their size due to the sieving effect of the agarose gel in gel electrophoresis.
Therefore the given statement (iv) in the question is correct.
Final answer
(d) i and ii
