Question

Assertion (A) Restriction endonucleases are also called ‘molecular scissors’.
Reason (R) When fragments generated by restriction endonucleases are mixed, they join together due to their sticky ends.

• A. If both A and R are true and R is the correct explanation of A
• B. If both A and R are true, but R is not the correct explanation of A
• C. If A is true, but R is false
• D. If A is false, but R is true

Answer 1

Answer: (B)

Both Assertion and Reason are true, but Reason is not the correct explanation of Assertion.
Restriction endonucleases are molecular scissors, as these enzymes cut a DNA molecule within certain specific sites called restriction sites.
When these fragments with sticky ends are mixed, they can be joined together (end to-end) using the enzyme, DNA ligase.