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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
Mention the difference in the mode of action of exonuclease and endonuclease.
How does a restriction nuclease function? Explain
Name and describe the technique that helps in separating the DNA fragments formed by the use of restriction endonuclease
Explain briefly:
Restriction enzymes and DNA
Answer the following question.
Explain the significance of palindromic nucleotide sequence in the formation of recombinant DNA.
Which of the given statements is correct in the context of visualizing DNA molecules separated by agarose gel electrophoresis?
While isolating DNA from bacteria, which of the following enzymes is not required?
CTTAAG
GAATTC
- What are such sequences called? Name the enzyme used that recognizes such nucleotide sequences.
- What is their significance in biotechnology?
Carefully observe the given picture. A mixture of DNA with fragments ranging from 200 base pairs to 2500 base pairs was electrophoresed on agarose gel with the following arrangement.
(a) What result will be obtained on staining with ethidium bromide? Explain with reason.
(b) The above setup was modified and a band with 250 base pairs was obtained at X.
What change(s) were made to the previous design to obtain a band at X? Why did the band appear at position X?
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
