Multiple choice

Assertion (A): Purines are complementary only with pyrimidines, where pyrimidine-pyrimidine pairing is energetically unfavorable. Reason (R): The molecules are too far apart for H-bonding to be formed.

  1. A and R both are correct and R is the correct explanation of A.

  2. A and R both are correct and R is not the correct explanation of A.

  3. A is correct and R is incorrect.

  4. A is incorrect and R is correct.

  5. A and R both are incorrect.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Purines can hydrogen bond only with pyrimidines, where pyrimidine-pyrimidine pairing is energetically unfavorable because the molecules are too far apart for H-bonding to be formed. Thus, this option is correct.

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