(a) What are ‘molecular scissors’ ? Give one. example.
(b) Explain their role in recombinant DNA technology.

Explanation

(a) There are restriction endoniicleases which cut the DN A molecule into fragments with sticky ends. e .g. ECORI cuts DNAbetween baSes G andA only when sequence GAATTC is present in the DNA .
he restriction enzymes cut the DNA strands a httle away from the centre of the palindromic sites,butbetween the same two bases on the opposite strands. This leaves single stranded portion with overhanging stretches called sticky ends on each strand as they form hydrogen bonds with their complementary cut counterparts. This stickiness at the ends facilitates the action of the enzyme DNA ligase.