NEET 2026 (Phase 1) · ChemistryNucleic acidsPrevious Year Question
The correct statement with regard to the secondary structure of DNA/RNA is
- A.RNA possesses a single-strand helix structure and contains thymine as one of the four bases
- B.DNA possesses a double-strand helix structure and contains thymine as one of the four bases✓
- C.RNA possesses a double-strand helix structure and contains uracil as one of the four bases
- D.DNA possesses a single-strand helix structure and contains uracil as one of the four bases
Correct Answer
(B) DNA possesses a double-strand helix structure and contains thymine as one of the four bases
Solution & Explanation
\textbf{Answer:} (B) DNA has a double-stranded helix and contains thymine among its four bases. \textbf{Solution:} The secondary structure of DNA is a double-stranded helix of two complementary polynucleotide chains, with four bases adenine (A), guanine (G), cytosine (C) and thymine (T). RNA is typically single-stranded and contains uracil (U) in place of thymine. Only option B correctly states a double-stranded helix containing thymine, so option B is correct.
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