JEE Main · 2021 · Shift-ImediumBIO-151

Out of following isomeric forms of uracil, which one is present in RNA?

Biomolecules · Class 12 · JEE Main Previous Year Question

Question

Out of following isomeric forms of uracil, which one is present in RNA? image image

Options
  1. a

    Option a

  2. b

    Option b

  3. c

    Option c

  4. d

    Option d

Correct Answerc

Option c

Detailed Solution

Step 1: Uracil Tautomerism — Like all nitrogenous bases, Uracil exists in tautomeric forms (amide/enol).

Step 2: Most Stable Form — In physiological conditions (pH 7), the diketoform is the dominant and most stable isomer.

Step 3: Identification — This structure involves two carbonyl (\ceC=O)(\ce{C=O}) groups at the C2 and C4 positions. Correct option is (c).

Key Point: The keto form correctly positions the hydrogen-bond donors and acceptors for base-pairing.

Practice this question with progress tracking

Want timed practice with adaptive difficulty? Solve this question (and hundreds more from Biomolecules) inside The Crucible, our adaptive practice platform.

Out of following isomeric forms of uracil, which one is present in RNA? (JEE Main 2021) | Canvas Classes