Each step of a metabolic pathway has its

Options

A. Own cofactor
B. Enzyme
C. Coenzyme
D. One to serveral enzymes.

Answer

### Step-by-Step Solution:

1. **Understanding Metabolic Pathways**:
- Metabolic pathways consist of a series of biochemical reactions that occur within a cell. These pathways can be classified into two main types: catabolic pathways and anabolic pathways.

2. **Types of Metabolic Pathways**:
- **Catabolic Pathways**: These pathways involve the breakdown of complex molecules into simpler ones, releasing energy in the process. Examples include glycolysis and the Krebs cycle.
- **Anabolic Pathways**: These pathways involve the synthesis of complex molecules from simpler ones, requiring energy input. Examples include lipogenesis and glycogenesis.

3. **Reactions in Metabolic Pathways**:
- Each metabolic pathway consists of multiple reactions, not just a single reaction. These reactions occur in a sequential manner, forming a cascade of biochemical processes.

4. **Role of Enzymes**:
- Each reaction in a metabolic pathway is catalyzed by a specific enzyme. Enzymes are crucial for increasing the rate of reactions, allowing metabolic processes to occur efficiently.

5. **Cofactors and Coenzymes**:
- Cofactors are non-protein molecules that assist enzymes in their activity. They can be metal ions or organic molecules.
- Coenzymes are a type of cofactor that are organic molecules, often derived from vitamins. They play a role in enzyme function but are not complete enzymes themselves.

6. **Conclusion**:
- Therefore, the correct answer to the question "Each step of a metabolic pathway has its own..." is that each reaction has its own enzyme. While cofactors and coenzymes may be involved, they are not unique to each step, and multiple reactions can share the same cofactor or coenzyme.

### Final Answer:
Each step of a metabolic pathway has its own enzyme.

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