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प्रश्न
Name and describe the technique that helps in separating the DNA fragments formed by the use of restriction endonuclease
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उत्तर
Gel electrophoresis is a technique of separating DNA fragments formed by the action of restriction endonucleases.
The fragments of DNA are placed in a typical agarose gel under an electric field. The DNA fragments move towards the anode as these fragments are negatively charged molecules. The DNA fragments separate according to their size through the sieving effect provided by the agarose gel. The smaller the fragment size, the farther it moves. The separated DNA fragments are stained with ethidium bromide followed by exposure to ultraviolet radiation. The DNA fragments are seen as orangecoloured and are cut out from the agarose gel and extracted from the gel piece. This step is called elution.
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संबंधित प्रश्न
Mention the difference in the mode of action of exonuclease and endonuclease.
How does restriction endonuclease function?
'Restriction' in restriction enzyme refers to
A specific recognition sequence identified by endonucleases to make cuts at specific positions within the DNA is ______
'Restriction' in Restriction enzyme refers to ______.
Restriction enzymes that are used in the construction of recombinant DNA are endonucleases which cut the DNA at ‘specific-recognition sequence’. What would be the disadvantage if they do not cut the DNA at specific-recognition sequence?
A plasmid DNA and a linear DNA (both are of the same size) have one site for a restriction endonuclease. When cut and separated on agarose gel electrophoresis, plasmid shows one DNA band while linear DNA shows two fragments. Explain.
Carefully observe the given picture. A mixture of DNA with fragments ranging from 200 base pairs to 2500 base pairs was electrophoresed on agarose gel with the following arrangement.
(a) What result will be obtained on staining with ethidium bromide? Explain with reason.
(b) The above setup was modified and a band with 250 base pairs was obtained at X.
What change(s) were made to the previous design to obtain a band at X? Why did the band appear at position X?
What is elution?
Given below is the restriction site of a restriction endonuclease Pst-I and the cleavage sites on a DNA molecule.
\[\ce{5' C - T - G - C - A \overset{\downarrow}{-}{G 3'}}\]
\[\ce{3' G\underset{\uparrow}{-} A - C - G - T - C 5'}\]
Choose the option that gives the correct resultant fragments by the action of the enzyme Pst-I.
