Q32 / 160 · AP EAMCET 2023 (15 May Shift 1) · Chemistry
Given below are two statements
Assertion (A): Hydrolysis of DNA does not form equal number of $A$ and $T ; G$ and $C$
Reason (R): In DNA adenine forms hydrogen bonds with thymine and cytosine forms hydrogen bonds with guanine
The correct answer is
- ABoth $\mathrm{A}$ and $\mathrm{R}$ are correct and $\mathrm{R}$ is the correct explanation of $\mathrm{A}$
- BBoth $\mathrm{A}$ and $\mathrm{R}$ are correct but $\mathrm{R}$ is not the correct explanation of $\dot{A}$
- C$\mathrm{A}$ is correct but $\mathrm{R}$ is incorrect
- Correct answerD$\mathrm{A}$ is incorrect but $\mathrm{R}$ is correct
Solution
The pairing of the two helices of DNA is such that $A$ pairs with $T$ and $G$ pairs with $C$, through hydrogen bonding.
Thus, number of $\mathrm{A}=$ number of $\mathrm{T}$
number of $\mathrm{G}=$ number of $\mathrm{C}$
Therefore, statement in Assertion (A) is wrong and Reason (R) is correct.
Hence, the correct answer is option: 'D'.