Which of the following values will depict correct respiratory quotient when tripalmitin (a fatty acid) is used as a respiratory substrate?

Options

A. `1.1`
B. 1
C. `0.7`
D. `0.9`

Answer

To determine the correct respiratory quotient (RQ) when tripalmitin, a fatty acid, is used as a respiratory substrate, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Respiratory Quotient (RQ)**:
- The respiratory quotient is defined as the ratio of the volume of carbon dioxide (CO2) produced to the volume of oxygen (O2) consumed during respiration.
- The formula for RQ is:
\[ RQ = \frac{CO2 \, \text{produced}}{O2 \, \text{consumed}} \]

2. **Identify the Chemical Formula of Tripalmitin**:
- Tripalmitin is a triglyceride composed of three palmitic acid molecules. Its chemical formula is \( C_{51}H_{98}O_6 \).

3. **Write the Balanced Reaction**:
- The complete oxidation of tripalmitin can be represented as:
\[ C_{51}H_{98}O_6 + O_2 \rightarrow CO_2 + H_2O \]
- For the complete combustion of tripalmitin, it is known that it requires approximately 72.5 molecules of O2 to produce 51 molecules of CO2 and 49 molecules of H2O.

4. **Calculate the RQ**:
- Using the values from the balanced reaction:
- CO2 produced = 51
- O2 consumed = 72.5
- Plugging these values into the RQ formula:
\[ RQ = \frac{51}{72.5} \]
- Performing the calculation:
\[ RQ = 0.7 \]

5. **Conclusion**:
- The respiratory quotient for tripalmitin is 0.7. Therefore, the correct answer is 0.7.