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प्रश्न
'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.
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उत्तर
(I) Restriction endonucleases are named as follows:
1st alphabet represents the genus of the organism from which the enzyme is isolated.
2nd and 3rd alphabet represent the species of the organism.
4th alphabet represents the strain.
The Roman number represents the order of isolation or discovery of the enzyme.
EcoRI comes from the Escherichia coli RYB strain.
In EcoRI, 'E' comes from the genus 'Escherichia' and 'co' comes from the species name 'Coli'.
The letter 'R' is derived from the name of the strain RYB.
Roman numbers following the names indicate the order in which the enzymes were isolated from that strain of bacteria.
(II) The recognition sequence where EcoRI cleaves the DNA molecule is G/AATTC. Such sequences have a complementary sequence, CTTAA/G, which is known as a palindromic sequence.
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संबंधित प्रश्न
Collect 5 examples of palindromic DNA sequences. Better try to create a palindromic sequence by following base-pair rules.
Which of the following radioisotope is not suitable for DNA labeling based studies?
Restriction enzymes ______.
Molecular scissors, which cut DNA at specific site is ______.
Which of the given statements is correct in the context of visualizing DNA molecules separated by agarose gel electrophoresis?
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?
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.
