Which of the following is a primary metabolite ?

Options

A. Carotenoids
B. Morphine
C. Glucose
D. Vinblastine

Answer

To determine which of the given options is a primary metabolite, we need to understand what primary metabolites are and analyze each option accordingly.

### Step-by-Step Solution:

1. **Define Primary Metabolites**:
- Primary metabolites are substances that are directly involved in the normal growth, development, and reproduction of an organism. They play crucial roles in metabolic processes.

2. **Analyze the Options**:
- **Option 1: Carotenoid** - Carotenoids are pigments found in plants and are considered secondary metabolites. They are not directly involved in growth and reproduction.
- **Option 2: Morphine** - Morphine is an alkaloid derived from the opium poppy and is classified as a secondary metabolite. It is not essential for the basic metabolic processes of the plant.
- **Option 3: Glucose** - Glucose is a simple sugar and is a primary metabolite. It is directly involved in energy production and is a key component of metabolic pathways.
- **Option 4: Benzoic Acid** - Benzoic acid is also a secondary metabolite and is not directly involved in the fundamental metabolic processes of growth and reproduction.

3. **Identify the Correct Answer**:
- Among the options, glucose is the only substance that fits the definition of a primary metabolite as it is directly involved in metabolic pathways and is essential for energy production.

### Conclusion:
- The correct answer is **Option 3: Glucose**.

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