Respiratory pathway involves both catabolic and anabolic pathways (amphibolic). Various intermediates of the pathway are precursors of various important compounds. Which of the following is incorrect in this respect?

Options

A. Acetyl CoA `rarr` Terpenes, gibberellins
B. Succinyl CoA `rarr` Chlorophyll, cytochrome
C. Oxaloacetic acid `rarr` Auxins, insulins, Glut 4
D. `alpha`-Ketogulutaric acid `rarr` Glutamic acid glutamine

Answer

To solve the question regarding the respiratory pathway and its intermediates, we will analyze each option provided to determine which statement is incorrect.

### Step-by-Step Solution:

1. **Understanding the Respiratory Pathway**:
- The respiratory pathway is amphibolic, meaning it includes both catabolic (breaking down molecules for energy) and anabolic (building up molecules) processes.
- Intermediates from this pathway can serve as precursors for various important compounds in the plant.

2. **Analyzing Each Option**:
- **Option 1**: Acetyl-CoA forms terpenes and gibberellins.
- Acetyl-CoA is indeed involved in the biosynthesis of terpenes and gibberellins, which are important compounds in plants. This statement is correct.

- **Option 2**: Oxaloacetic acid (OAA) forms auxin, insulin, and glutathione.
- Oxaloacetic acid is involved in the synthesis of auxins and glutathione, but it does not form insulin. Insulin is a hormone produced in the pancreas, not through the respiratory pathway. Therefore, this statement is incorrect.

- **Option 3**: Alpha-ketoglutaric acid forms glutamic acid.
- Alpha-ketoglutaric acid is a key intermediate in the Krebs cycle and is indeed a precursor for glutamic acid. This statement is correct.

3. **Conclusion**:
- The incorrect statement is from **Option 2**, where it claims that oxaloacetic acid forms insulin. This is not true as insulin is not synthesized through the respiratory pathway.

### Final Answer:
The incorrect statement is: **Oxaloacetic acid forms insulin.**