NEETZoologyBiotechnology - Principles and Processes
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): The stickiness of DNA ends produced by certain restriction enzymes facilitates the action of the enzyme DNA ligase. Reason (R): Restriction endonucleases cut the strand of DNA a little away from the centre of the palindrome sites. In the light of the above statements, choose the most appropriate an
Options
- ABoth Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
- BBoth Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
- CAssertion (A) is true but Reason (R) is false.
- DAssertion (A) is false but Reason (R) is true.
Correct answer
B. Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
Step-by-step solution
Assertion (A) is true because the sticky ends form temporary hydrogen bonds with their complementary cut counterparts. This brings the DNA fragments close together, which facilitates the joining action of DNA ligase to form phosphodiester bonds. Reason (R) is also true because restriction enzymes that produce sticky ends do so by cutting the DNA strand a little away from the centre of the palindrome sites, but between the same two bases on the opposite strands. However, Reason (R) explains how sticky ends are forme