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प्रश्न
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.
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उत्तर
It is because plasmid is a circular DNA molecule. When cut with enzyme, it becomes linear but does not get fragmented. Whereas, a linear DNA molecule gets cut into two fragments. Hence, a single DNA band is observed for plasmid while two DNA bands are observed for linear DNA in agarose gel.
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संबंधित प्रश्न
Explain with the help of a suitable example the naming of a restriction endonuclease.
How are 'sticky ends' formed on a DNA strand? Why are they so called?
Suggest a technique to a researcher who needs to separate fragments of DNA.
Name and describe the technique that helps in separating the DNA fragments formed by the use of restriction endonuclease
Collect 5 examples of palindromic DNA sequences. Better try to create a palindromic sequence by following base-pair rules.
Answer the following question.
Explain the significance of palindromic nucleotide sequence in the formation of recombinant DNA.
Answer the following question.
Write the use of restriction endonuclease in the formation of recombinant DNA.
Give a reason why :
Single cloning site is preferred in a vector.
'Restriction' in Restriction enzyme refers to ______.
While isolating DNA from bacteria, which of the following enzymes is not required?
The role of DNA ligase in the construction of a recombinant DNA molecule is ______.
Which of the following statements does not hold true for restriction enzyme?
Restriction enzymes should not have more than one site of action in the cloning site of a vector. Comment.
How does one visualise DNA on an agarose gel?
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?
State the importance of elution in this process.
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.
