Which of the following aerobic respiratory substrates have the same yield of ATP

Options

A. Glucose, Glucose 6P, Fructose 6P
B. 3PGA, 2PGA, PEP
C. Pyruvic acid, Acetyl Co.A, Citric acid
D. Isocitric acid, Oxalosuccinic acid, `alpha`-Ketoglutaric acid

Answer

To solve the question of which aerobic respiratory substrates yield the same amount of ATP, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: The question asks us to identify which of the given aerobic respiratory substrates yield the same amount of ATP during respiration.

2. **Identify the Options**: The options provided are:
- Option 1: Glucose, Glucose 6-phosphate, Fructose 6-phosphate
- Option 2: 3-PGA, 2-PGA, PEP
- Option 3: Pyruvic acid, Acetyl-CoA, Citric acid
- Option 4: Isocitric acid, Oxaloacetic acid, Alpha-ketoglutaric acid

3. **Analyze Each Option**:
- **Option 1**: Glucose, Glucose 6-phosphate, Fructose 6-phosphate are involved in glycolysis. The conversion of glucose to glucose 6-phosphate and then to fructose 6-phosphate does not yield the same amount of ATP.
- **Option 2**: 3-PGA (3-Phosphoglycerate), 2-PGA (2-Phosphoglycerate), and PEP (Phosphoenolpyruvate) are intermediates in glycolysis and the ATP yield from these substrates is consistent.
- **Option 3**: Pyruvic acid, Acetyl-CoA, and Citric acid involve different metabolic pathways including fatty acid oxidation and do not yield the same amount of ATP.
- **Option 4**: Isocitric acid, Oxaloacetic acid, and Alpha-ketoglutaric acid are part of the citric acid cycle (Krebs cycle) and also do not yield the same ATP.

4. **Conclusion**: The only option where the substrates yield the same amount of ATP is **Option 2: 3-PGA, 2-PGA, and PEP**.

### Final Answer:
The correct answer is **Option 2: 3-PGA, 2-PGA, and PEP**.

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