Respiratory quotient may be represented as

Options

A. `O_(2)` taken in `//CO_(2)` evolved
B. `CO_(2)` evolved `//O_(2)` taken in
C. `O_(2)` taken in
D. `CO_(2)` taken in

Explanation

**Step-by-Step Solution:**

1. **Definition of Respiratory Quotient (RQ):** The respiratory quotient is defined as the ratio of the volume of carbon dioxide produced (CO2) to the volume of oxygen consumed (O2) during respiration.

2. **Mathematical Representation:** The respiratory quotient (RQ) can be mathematically represented as:
\[ RQ = \frac{\text{CO}_2 \text{ produced}}{\text{O}_2 \text{ consumed}} \]

3. **Measurement of RQ:** The respiratory quotient is used to measure the basal metabolic rate (BMR) of an organism. It indicates how efficiently the body is using different substrates for energy.

4. **Instruments Used:** The measurement of RQ is typically done using a respirometer, which helps in quantifying the amounts of oxygen consumed and carbon dioxide produced.

5. **RQ Values for Different Substrates:** Different substrates yield different RQ values:
- For carbohydrates, the RQ is approximately 1.0.
- For proteins, the RQ is about 0.8.
- For lipids, the RQ is around 0.7.

6. **Conclusion:** Thus, the respiratory quotient can be represented as the ratio of carbon dioxide produced to oxygen consumed, and it varies based on the type of substrate being metabolized.

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