Which is not found in DNA ?

Options

A. Deoxy ribose sugar
B. 5-methyl uracil
C. Demethylated thymine
D. `H_(3)PO_(4)`

Answer

To determine which component is not found in DNA, we need to analyze the options provided:

1. **Deoxyribose Sugar**:
- DNA stands for deoxyribonucleic acid, indicating that it contains deoxyribose sugar as part of its structure. This sugar is a crucial component of the DNA backbone.
- **Conclusion**: This option is found in DNA.

2. **5-Methyluracil**:
- Uracil is a nitrogenous base that is found in RNA, not in DNA. The presence of a methyl group on uracil (making it 5-methyluracil) does not change its identity as a base that is exclusive to RNA.
- **Conclusion**: This option is not found in DNA.

3. **Demethylated Thymine**:
- Thymine is one of the four nitrogenous bases found in DNA. Even if it is demethylated, thymine remains a part of the DNA structure.
- **Conclusion**: This option is found in DNA.

4. **Phosphoric Acid**:
- Phosphoric acid forms the phosphate group that is part of the DNA backbone. Therefore, it is an essential component of DNA.
- **Conclusion**: This option is found in DNA.

After analyzing all the options, the only component that is not found in DNA is **5-methyluracil**.

**Final Answer**: 5-methyluracil is not found in DNA.

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