Which of the following respiratory substances requires the highest number of `O_(2)` molecules for its complete oxidaiton.

Options

A. Triolein
B. Oleic acid
C. Tripalmitin
D. Tartaric acid.

Answer

To determine which respiratory substance requires the highest number of oxygen (O₂) molecules for complete oxidation, we need to analyze the respiratory quotient (RQ) of each substance provided in the options. The respiratory quotient is a measure of the ratio of carbon dioxide produced to oxygen consumed during respiration. Substances that are less oxidized require more oxygen for complete oxidation, while those that are more oxidized require less.

### Step-by-Step Solution:

1. **Understand the Concept of Respiratory Quotient (RQ):**
- RQ is defined as the ratio of carbon dioxide produced to oxygen consumed during respiration.
- A lower RQ indicates that more oxygen is required for the complete oxidation of the substrate.

2. **List the Given Substances and Their RQs:**
- Triolene: RQ = 0.7
- Oleic Acid: RQ = 1.6
- Tripalmitin: RQ = 0.7
- Tartaric Acid: RQ = 1.3

3. **Analyze the RQs:**
- Triolene and Tripalmitin have the lowest RQ of 0.7, indicating they require more oxygen for oxidation.
- Oleic Acid and Tartaric Acid have higher RQs (1.6 and 1.3 respectively), indicating they require less oxygen for oxidation.

4. **Determine Which Substance Requires the Most Oxygen:**
- Since Triolene and Tripalmitin have the lowest RQ, they require the highest number of O₂ molecules for complete oxidation.
- However, since both Triolene and Tripalmitin have the same RQ, we can conclude that they both require the highest number of oxygen molecules.

5. **Final Conclusion:**
- The correct answer is **Triolene**, as it is one of the substances with the lowest RQ, indicating it requires the highest number of O₂ molecules for complete oxidation.