JEE Main · 2025 · Shift-ImediumBIO-006

The carbohydrate "Ribose" present in DNA, is A. A pentose sugar B. present in pyranose form C. in "D" configuration D.…

Biomolecules · Class 12 · JEE Main Previous Year Question

Question

The carbohydrate "Ribose" present in DNA, is

A. A pentose sugar
B. present in pyranose form
C. in "D" configuration
D. a reducing sugar, when free
E. in α\alpha-anomeric form

Choose the correct answer from the options given below:

Options
  1. a

    A, D and E Only

  2. b

    B, D and E Only

  3. c

    A, B and E Only

  4. d

    A, C and D Only

Correct Answerd

A, C and D Only

Detailed Solution

Step 1: Pentose Classification — Ribose is a five-carbon sugar, making it a pentose. In nucleic acids, it typically exists in the D-configuration\text{D-configuration}.

Step 2: Chemical Properties — Free ribose exists in an equilibrium that includes an open-chain form with a free aldehyde group, making it a reducing sugar.

Step 3: Structural Form — While it can form a pyranose ring when free, in the context of nucleotides it adopts a furanose (5-membered) ring structure. The correct descriptors are A, C, and D.

Key Point: DNA contains 2-deoxy-D-ribose\text{D-ribose}, while RNA contains D-ribose\text{D-ribose}.

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The carbohydrate "Ribose" present in DNA, is A. A pentose sugar B. present in pyranose form C. in… (JEE Main 2025) | Canvas Classes