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प्रश्न
How are 'sticky ends' formed on a DNA strand? Why are they so called?
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उत्तर
Sticky ends are produced by restriction enzymes. These enzymes cut the strand of DNA a little away from the centre of the palindrome sites but between the same two bases on the opposite strands. This leaves single stranded portions at the ends. There are overhanging stretches called 'sticky ends' on each strand.
These are called sticky ends because they form hydrogen bonds with their complementary cut counterparts. This stickiness of the ends facilitates the action of the enzyme DNA ligase.
संबंधित प्रश्न
Why is the enzyme cellulase needed for isolating genetic material from plant cells and not form the animal cells?
Mention the difference in the mode of action of exonuclease and endonuclease.
Collect 5 examples of palindromic DNA sequences. Better try to create a palindromic sequence by following base-pair rules.
How does restriction endonuclease function?
Explain the roles of the following with the help of an example each in recombinant DNA technology :
Restriction Enzymes
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.
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?
Hind II always cuts DNA molecules at a particular point called recognition sequence and it consists of ______.
How are separated DNA bands visualized following agarose gel electrophoresis?
