An amphibolic pathway is

Options

A. TCA cycle
B. Calvin cycle
C. Terminal oxidation
D. Electron transport chain.

Answer

### Step-by-Step Solution:

1. **Understanding the Term "Amphibolic Pathway":**
- An amphibolic pathway is a metabolic pathway that involves both catabolic and anabolic processes. This means it can break down molecules to produce energy (catabolism) and also synthesize complex molecules (anabolism).

2. **Identifying the Correct Pathway:**
- Among the options provided, we need to identify which pathway is known as an amphibolic pathway. The options given are:
- a) TCA cycle
- b) Calvin cycle
- c) Terminal oxidation
- d) Electron transport chain

3. **Analyzing the TCA Cycle (Kreb Cycle):**
- The TCA cycle, also known as the Kreb cycle, is a series of biochemical reactions that occurs in the mitochondria. It is an 8-step cycle that begins with the combination of a 2-carbon molecule (acetyl coenzyme A) and a 4-carbon molecule (oxaloacetate).

4. **Function of the TCA Cycle:**
- In the TCA cycle, acetyl coenzyme A is degraded to produce carbon dioxide and energy. This process generates important energy carriers such as NADH and FADH2, which are crucial for cellular respiration.

5. **Conclusion:**
- Since the TCA cycle involves both the breakdown of molecules (catabolic) and the synthesis of energy carriers (anabolic), it is classified as an amphibolic pathway. Therefore, the correct answer to the question is the TCA cycle.

### Final Answer:
The amphibolic pathway is the TCA cycle (Kreb cycle).

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