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प्रश्न
Which of the following enzymes catalyse the removal of nucleotides from the ends of DNA?
पर्याय
Endonuclease
Exonuclease
DNA ligase
Hind - II
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उत्तर
Exonuclease
Explanation:
The enzyme that catalyzes the removal of nucleotides from the ends of DNA is exonuclease. Exonuclease specifically removes nucleotides one by one from the ends of a DNA strand, whereas endonucleases cut DNA at internal sites. DNA ligase joins DNA fragments but does not remove nucleotides. Hind II is a type of restriction endonuclease that cuts DNA at specific internal sequences, not at the ends.
संबंधित प्रश्न
Mention the difference in the mode of action of exonuclease and 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.
Explain the roles of the following with the help of an example each in recombinant DNA technology :
Restriction Enzymes
Give a reason why :
Single cloning site is preferred in a vector.
There is a restriction endonudease called as EcoRI. What does co part in it stands for?
DNA fragments separate according to size through?
A specific recognition sequence identified by endonucleases to make cuts at specific positions within the DNA is ______
Which of the given statements is correct in the context of visualizing DNA molecules separated by agarose gel electrophoresis?
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 ______.
Which of the following bacteria is not a source of restriction endonuclease?
Which of the following statements does not hold true for restriction enzyme?
Would you choose an exonuclease while producing a recombinant DNA molecule?
Restriction enzymes should not have more than one site of action in the cloning site of a vector. Comment.
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?
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?
State the importance of elution in this process.
'EcoRI' has played a very significant role in rDNA technology.
- Explain the convention for naming EcoRI.
- Write the recognition site and the cleavage sites of this restriction endonuclease.
What are the protruding and hanging stretches of DNA produced by these restriction enzymes called? Describe their role in the formation of rDNA.
How are DNA fragments visualised once they are separated by gel electrophoresis?
Identify the activity of endonuclease and exonuclease in the given image.
Which of the following was the very first restriction endonuclease to be isolated and characterized?
Which of the following represents the specific palindromic recognition sequence cleaved by the restriction endonuclease EcoRI?
According to the sieving effect of an agarose gel matrix, which DNA fragments move the farthest and fastest from the loading wells?
How are separated DNA bands visualized following agarose gel electrophoresis?
Why are Type II restriction endonucleases the primary class of restriction enzymes used in genetic manipulation?
