Catabolic and anabolic pathways are often coupled in cell because -

Options

A. The intermediates of a catabolic pathway are used in the anabolic pathway
B. Both the pathway use the same energy
C. The free energy released from one pathway is used to drive other
D. Their enzymes are controlled by their same activators and inhibitors

Answer

**Step-by-Step Solution:**

1. **Understanding Catabolic Pathways:**
- Catabolic pathways are metabolic processes that break down large molecules into smaller ones. This breakdown releases energy, which is often in the form of ATP (adenosine triphosphate).

2. **Understanding Anabolic Pathways:**
- Anabolic pathways are the opposite of catabolic pathways. They involve the synthesis of large molecules from smaller ones. This process requires an input of energy, as it is building complex structures from simpler units.

3. **Coupling of Catabolic and Anabolic Pathways:**
- In cellular metabolism, catabolic and anabolic pathways are often coupled. This means that the energy released from catabolic reactions is used to drive anabolic reactions. Essentially, the energy produced during the breakdown of molecules is harnessed to build new molecules.

4. **Energy Transfer:**
- The energy released from catabolic pathways (e.g., during the breakdown of glucose) is utilized in anabolic pathways (e.g., during the synthesis of proteins). This coupling ensures that energy is efficiently used within the cell.

5. **Correct Answer:**
- The correct reason why catabolic and anabolic pathways are coupled is that the free energy released from one pathway is used to drive the other pathway. Thus, the correct answer is: "The free energy released from one pathway is used to derive the other."