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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
Mention the difference in the mode of action of exonuclease and endonuclease.
Name the enzymes that are used for the isolation of DNA from bacterial and fungal cells for recombinant DNA technology.
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.
Explain the roles of the following with the help of an example each in recombinant DNA technology :
Restriction Enzymes
Answer the following question.
Explain the significance of palindromic nucleotide sequence in the formation of recombinant DNA.
Give a reason why :
Single cloning site is preferred in a vector.
The DNA fragment separated on an agarose gel can be visualized by staining with ______.
A mixture containing DNA fragments a, b, c and d, with molecular weights of a + b = c, a > b and d > c was subject to agarose get electrophoresis. This position of these fragments from cathode to anode to anode sides of the gel would be ______.
Restriction enzymes ______.
A specific recognition sequence identified by endonucleases to make cuts at specific positions within the DNA is ______
In agarose gel electrophoresis, DNA molecules are separated on the basis of their ______.
The role of DNA ligase in the construction of a recombinant DNA molecule is ______.
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?
State the importance of elution in this process.
How are DNA fragments visualised once they are separated by gel electrophoresis?
Identify the activity of endonuclease and exonuclease in the given image.
