When protein is aerobically oxidised, the R.Q. value will be

Options

A. One
B. Zero
C. More than one
D. Less than one

Answer

To determine the respiratory quotient (R.Q.) value when protein is aerobically oxidized, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Definition of R.Q.**:
The respiratory quotient (R.Q.) is defined as the ratio of the volume of carbon dioxide (CO2) produced to the volume of oxygen (O2) consumed during respiration. Mathematically, it is expressed as:
\[ R.Q. = \frac{\text{CO2 evolved}}{\text{O2 consumed}} \]

2. **Identify the Substrate**:
In this case, the substrate is protein. When proteins are used as a source of energy, they undergo aerobic oxidation.

3. **Know the R.Q. Values for Different Substrates**:
- Carbohydrates have an R.Q. of approximately 1.0.
- Fats have an R.Q. of approximately 0.7.
- Proteins have an R.Q. value that typically ranges from 0.8 to 0.9.

4. **Determine the R.Q. for Proteins**:
Since proteins are being aerobically oxidized, we refer to the known R.Q. value for proteins, which is around 0.8 to 0.9. This indicates that the amount of CO2 produced is less than the amount of O2 consumed.

5. **Evaluate the Options**:
Given the options:
- 1 (incorrect, as this is for carbohydrates)
- 0 (incorrect, as this implies no CO2 is produced)
- More than 1 (incorrect, as this is for organic acids)
- Less than 1 (correct, as proteins have an R.Q. of 0.8 to 0.9)

6. **Conclusion**:
Therefore, the correct answer is that when protein is aerobically oxidized, the R.Q. value will be less than 1.

### Final Answer:
The R.Q. value when protein is aerobically oxidized will be less than 1.

---