Question

(a) Write the palindromic nucleotide for the following DNA segment:
5-G AA TTC-3
(b)Name the restriction endonuclease that recognises the sequence

(C)How are sticky-ends produced ? Mention their role.

Answer 1

1. 5' GAATTC 3'

3' CTTAAG 5'

2. EcoR 1

3. Sticky ends are produced by the restriction enzymes. These enzymes cut the strand of DNA a little away from the center of palindrome sites but between the same two bases on the opposite strands. This leaves single-stranded portions at the end. These overhanging stretches are called sticky ends. These are called sticky ends because they form hydrogen bonds with the complementary cut counterparts. This stickiness of the ends facilitates the action of enzyme DNA ligase.