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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
Explain with the help of a suitable example the naming of a restriction endonuclease.
Name and describe the technique that helps in separating the DNA fragments formed by the use of 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?
Explain the roles of the following with the help of an example each in recombinant DNA technology :
Restriction Enzymes
Answer the following question.
Write the use of restriction endonuclease in the formation of recombinant DNA.
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 ______.
There is a restriction endonudease called as EcoRI. What does co part in it stands for?
Molecular scissors, which cut DNA at specific site is ______.
'Restriction' in restriction enzyme refers to
DNA strands on a gel stained with ethidium bromide when viewed under UV radiation, appear as ______
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 ______.
While isolating DNA from bacteria, which of the following enzymes is not required?
Which of the following bacteria is not a source of restriction endonuclease?
What does H in’ ‘d’ and ‘III’ refer to in the enzyme Hind III?
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 plasmid DNA and a linear DNA (both are of the same size) have one site for a restriction endonuclease. When cut and separated on agarose gel electrophoresis, plasmid shows one DNA band while linear DNA shows two fragments. Explain.
Given below is the stepwise schematic representation of the process of electrophoresis. Identify the 'alphabets' representing
- Anode end
- smallest/lightest DNA strand in the matrix
- Agarose gel

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.
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 ______.
