Which of the following compounds in not a vitamin ?

Options

A. Niacin
B. Riboflavin
C. Thiamine
D. Guanine

Answer

To determine which of the following compounds is not a vitamin, we will analyze each option one by one.

1. **Niacin**:
- Niacin is known as Vitamin B3. It plays an essential role in energy metabolism and is important for the health of the skin, nerves, and digestive system.
- Conclusion: Niacin is a vitamin.

2. **Riboflavin**:
- Riboflavin is known as Vitamin B2. It is crucial for energy production and the metabolism of fats, drugs, and steroids.
- Conclusion: Riboflavin is a vitamin.

3. **Thiamine**:
- Thiamine is known as Vitamin B1. It is important for carbohydrate metabolism and plays a key role in nerve, muscle, and heart function.
- Conclusion: Thiamine is a vitamin.

4. **Guanine**:
- Guanine is a nitrogenous base that is part of the genetic material in DNA and RNA. It belongs to the category of purines and is not classified as a vitamin.
- Conclusion: Guanine is not a vitamin.

After analyzing all the options, we find that the compound that is not a vitamin is **Guanine**.

**Final Answer**: Guanine is not a vitamin.

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