Class 12th Biology 2014 Set1 Delhi Board Paper Solution
Question 18
How are 'sticky ends' formed on a DNA strand? Why are they so called?
Answer
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.
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