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प्रश्न
Explain briefly:
Restriction enzymes and DNA
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उत्तर
Restriction enzymes are used to break up DNA molecules. They are part of a broader enzyme class known as nucleases. Restriction enzymes are classified into three types:
- Exonucleases: They remove nucleotides from the terminal ends (5' or 3') of one double strand of DNA.
- Endonucleases: They make cuts at specific positions within the DNA. These enzymes don’t fragment the ends and only affect one strand of the DNA helix.
- Restriction endonucleases: Arber identified them in bacteria in 1963. They function as “molecular scissors” or chemical scalpels. They detect the base sequence at palindrome sites in DNA sequences and sever the strands. There are three types of restriction endonucleases: type I, type II, and type III. Only type II restriction enzymes are utilised in recombinant DNA technology because they can recognise and cut inside a specified DNA sequence, typically consisting of 4 to 8 nucleotides.
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संबंधित प्रश्न
How are 'sticky ends' formed on a DNA strand? Why are they so called?
Why is the enzyme cellulase needed for isolating genetic material from plant cells and not form the animal cells?
How does a restriction nuclease function? Explain
Do eukaryotic cells have restriction endonucleases? Justify your answer.
Collect 5 examples of palindromic DNA sequences. Better try to create a palindromic sequence by following base-pair rules.
Distinguish between exonuclease and endonuclease.
Explain the roles of the following with the help of an example each in recombinant DNA technology :
Restriction Enzymes
Answer the following question.
Explain the significance of palindromic nucleotide sequence in the formation of recombinant DNA.
Give a reason why :
Single cloning site is preferred in a vector.
'Restriction' in restriction enzyme refers to
Which of the following enzymes catalyse the removal of nucleotides from the ends of DNA?
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 ______.
The role of DNA ligase in the construction of a recombinant DNA molecule is ______.
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?
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?
What are the protruding and hanging stretches of DNA produced by these restriction enzymes called? Describe their role in the formation of rDNA.
State the principle involved in separation of DNA fragments using gel electrophoresis.
Identify the activity of endonuclease and exonuclease in the given image.
