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प्रश्न
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?
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उत्तर
If the restriction enzymes would cut DNA at random sites instead of at specific sites, then the DNA fragments obtained will not have ‘sticky ends’. In the absence of sticky ends, construction of recombinant DNA molecules would not be possible.
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संबंधित प्रश्न
Explain with the help of a suitable example the naming of a restriction endonuclease.
Make a chart (with diagrammatic representation) showing a restriction enzyme, the substrate DNA on which it acts, the site at which it cuts DNA and the product it produces.
How does restriction endonuclease function?
Which of the following radioisotope is not suitable for DNA labeling based studies?
DNA strands on a gel stained with ethidium bromide when viewed under UV radiation, appear as ______
Which of the following enzymes catalyse the removal of nucleotides from the ends of DNA?
'Restriction' in Restriction enzyme refers to ______.
The role of DNA ligase in the construction of a recombinant DNA molecule is ______.
Which of the following bacteria is not a source of restriction endonuclease?
Which of the following statements does not hold true for restriction enzyme?
What does H in’ ‘d’ and ‘III’ refer to in the enzyme Hind III?
How does one visualise DNA on an agarose gel?
A mixture of fragmented DNA was electrophoresed in an agarose gel. After staining the gel with ethidium bromide, no DNA bands were observed. What could be the reason?
CTTAAG
GAATTC
- What are such sequences called? Name the enzyme used that recognizes such nucleotide sequences.
- What is their significance in biotechnology?
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.
What are the protruding and hanging stretches of DNA produced by these restriction enzymes called? Describe their role in the formation of rDNA.
