Question

Assertion (A) : Vector DNA and foreign DNA are cut by the same restriction enzyme.

Reason (R) : Vector DNA and foreign DNA, cut with same enzyme, produces complimentary sticky ends.

• A. Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation for Assertion (A).
• B. Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation for Assertion (A).
• C. Assertion (A) is true, but Reason (R) is false.
• D. Assertion (A) is false, but Reason (R) is true.

Hint:

The same enzyme leaves the same sticky ends on vector and foreign DNA, so they can pair and be joined.

Answer 1

The Correct Option is A

Step 1: Check the Assertion:
In recombinant DNA technology the vector and the DNA of interest are cut with the same restriction enzyme. So Assertion (A) is true.

Step 2: Check the Reason:
A restriction enzyme cuts at a specific palindromic sequence and leaves single-stranded overhangs, called sticky ends.
The same enzyme gives the same overhangs on both pieces, so the ends are complementary. Reason (R) is true.

Step 3: Link them:
The ends can pair by hydrogen bonding and DNA ligase seals them. This is why the same enzyme is used.
R explains A. The answer is option (A).

Final Answer:
Both are true and R explains A, so the answer is option (A).