Which of the following restriction enzymes produces blunt ends?
Answer: (B) Eco RV. Answer: (B) Eco RV Solution: Restriction enzymes that cut both strands exactly at the centre of the palindrome leave flush/blunt ends, while those that cut a little away from the centre (between the same two bases on opposite strands) leave single-stranded overhangs called sticky ends; EcoRV cuts at the centre giving blunt ends, whereas Sal I, Xho I and Hind III leave sticky (overhanging) ends.
- A.Sal I
- B.Eco RV✓
- C.Xho I
- D.Hind III
Correct Answer
(B) Eco RV
Solution & Explanation
Answer: (B) Eco RV Solution: Restriction enzymes that cut both strands exactly at the centre of the palindrome leave flush/blunt ends, while those that cut a little away from the centre (between the same two bases on opposite strands) leave single-stranded overhangs called sticky ends; EcoRV cuts at the centre giving blunt ends, whereas Sal I, Xho I and Hind III leave sticky (overhanging) ends. NCERT describes the sticky-end mechanism explicitly; the specific blunt-cutter EcoRV is an NCERT-extension example consistent with that mechanism (NCERT names EcoRI/Hind II/Hind III but not EcoRV by enzyme-specific cut, so cited line is the closest mechanistic anchor). NCERT Reference: Ch 9, p.167, line(s) 8-10 — "Restriction enzymes cut the strand of DNA a little away from the centre"