Q75 (2024)
The correct statement with regard to the secondary structure of DNA/RNA is:
- (1) DNA possesses a single strand helix structure and contains uracil as one of the four bases
- (2) RNA possesses a single strand helix structure and contains thymine as one of the four bases
- (3) DNA possesses a double strand helix structure and contains thymine as one of the four bases
- (4) RNA possesses a double strand helix structure and contains uracil as one of the four bases
### Related Formula
$$\text{DNA: Double helix (Bases: A, G, C, T)}, \quad \text{RNA: Single stranded (Bases: A, G, C, U)}$$
### Core Logic
DNA secondary structure consists of a double-stranded helix holding thymine (T) along with adenine, guanine, and cytosine. RNA is typically single-stranded containing uracil.
### Step 1: Conclusion
Statement (3) is correct.
### Pattern Recognition
DNA = Double stranded + Thymine; RNA = Single stranded + Uracil.
### Evaluation Rubric / Model Answer
null
### Chapter Mix
Class 12 Chemistry: Biomolecules
