Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). In the light of the above statements, choose the correct answer from the options given below :
- (A) is not correct but (R) is correct
- Both (A) and (R) are correct and (R) is the correct explanation of (A)
- Both (A) and (R) are correct but (R) is not the correct explanation of (A)
- (A) is correct but (R) is not correct
Answer
(2) Both (A) and (R) are correct and (R) is the correct explanation of (A)
Solution
As per NCERT, restriction 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, i.e. overhanging stretches called sticky ends on each strand.
∴ (A) is correct, (R) is correct, and the off-centre cut in (R) is the reason why sticky ends in (A) are formed.
Answer: (2)