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Assertion: In a DNA molecule, A–T rich parts melt before G–C rich parts. Reason: : In between A and T there are three H–bond, whereas in between G and C there are two H-bonds. |
Both Assertion (A) and reason(R) are correct and R is the correct explanation of A. Both Assertion (A) and reason (R) are correct but R is not the correct explanation of A. Assertion (A) is true but Reason(R) is not correct. Both Assertion (A) and Reason are false (F ). |
Assertion (A) is true but Reason(R) is not correct. |
The correct answer is Option (3)- Assertion (A) is true but Reason(R) is not correct. Assertion: In a DNA molecule, A–T rich parts melt before G–C rich parts. Reason: In between A and T there are three hydrogen bonds, whereas in between G and C there are two hydrogen bonds. Explanation: The assertion is correct because A-T base pairs have two hydrogen bonds, making them relatively weaker compared to G-C base pairs, which have three hydrogen bonds. During the process of DNA melting (or denaturation), the weaker A-T rich regions will melt (separate) before the G-C rich regions. However, the reason given is not correct. The correct information is that A-T base pairs have two hydrogen bonds, while G-C base pairs have three hydrogen bonds. The difference in the number of hydrogen bonds contributes to the stability of the DNA double helix. |
