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प्रश्न
How does a restriction nuclease function? Explain
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उत्तर
Restriction endonuclease functions by recognising its specific sequence. It binds to the DNA and cuts each to the two strands of the double helix at specific points in their sugar phosphate backbones. These enzymes cut the strand of DNA between the same two bases on the opposite strands leaving a single-stranded portion at their ends. These overhanging stretches are called sticky ends on each strand. The enzyme DNA ligase functions depending on the stickiness of these ends. For example, the restriction endonuclease EcoRI found in the colon bacteria E. coli recognises the base sequence GAATTC in the DNA duplex and cuts its strands between G and A.
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संबंधित प्रश्न
Suggest a technique to a researcher who needs to separate fragments of DNA.
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.
Collect 5 examples of palindromic DNA sequences. Better try to create a palindromic sequence by following base-pair rules.
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.
CTTAAG
GAATTC
- What are such sequences called? Name the enzyme used that recognizes such nucleotide sequences.
- What is their significance in biotechnology?
What are the protruding and hanging stretches of DNA produced by these restriction enzymes called? Describe their role in the formation of rDNA.
Hind II always cuts DNA molecules at a particular point called recognition sequence and it consists of ______.
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?
What is the process called when desired, separated DNA bands are physically cut out from the agarose gel and extracted from the gel piece?
