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प्रश्न
Explain briefly:
Restriction enzymes and DNA
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उत्तर
Restriction enzymes belong to a larger class of enzymes called nucleases. They are mainly classified into two types:
- Exonucleases: They remove nucleotides from the terminal ends of the DNA molecule.
- Endonucleases: They make cuts at specific positions anywhere within the DNA molecule.
Restriction endonucleases are a specific class of endonucleases that recognise palindromic nucleotide sequences and cleave DNA at specific sites. They cut both strands of the DNA double helix at specific points to generate sticky or blunt ends, which are essential for creating recombinant DNA.
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संबंधित प्रश्न
How are 'sticky ends' formed on a DNA strand? Why are they so called?
How does a restriction nuclease function? Explain
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.
Which of the following radioisotope is not suitable for DNA labeling based studies?
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?
'Restriction' in Restriction enzyme refers to ______.
In agarose gel electrophoresis, DNA molecules are separated on the basis of their ______.
Which of the following statements does not hold true for restriction enzyme?
Would you choose an exonuclease while producing a recombinant DNA molecule?
What does H in’ ‘d’ and ‘III’ refer to in the enzyme Hind III?
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?
How does one visualise DNA on an agarose gel?
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?
'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.
How are DNA fragments visualised once they are separated by gel electrophoresis?
Hind II always cuts DNA molecules at a particular point called recognition sequence and it consists of ______.
What is the precise definition of a palindromic sequence in DNA?
Which of the following was the very first restriction endonuclease to be isolated and characterized?
How do exonucleases differ fundamentally from endonucleases in their enzymatic site of action?
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?
