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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
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.
Distinguish between exonuclease and endonuclease.
Explain the roles of the following with the help of an example each in recombinant DNA technology :
Restriction Enzymes
The total number of nucleotide sequences of DNA that code for a hormone is 1530. The proportion of different bases in the sequence is found to be Adenine = 34%, Guanine = 19%, Cytosine = 23%, Thymine = 19%.
Applying Chargaff’s rule, what conclusion can be drawn?
'Restriction' in restriction enzyme refers to
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 following enzymes catalyse the removal of nucleotides from the ends of DNA?
In agarose gel electrophoresis, DNA molecules are separated on the basis of their ______.
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?
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?
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?
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.
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?
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?
In the restriction endonuclease EcoRI, what do the letter 'R' and the Roman numeral 'I' represent?
What is the origin of agarose, the matrix most commonly used in gel electrophoresis?
How are separated DNA bands visualized following agarose gel electrophoresis?
