R.Q. indicates

Options

A. Effect of temperature
B. Nature of respiratory substrate
C. Amount of water released
D. Type of alcohol formed.

Answer

**Step-by-Step Solution:**

1. **Understanding R.Q.:** R.Q. stands for Respiratory Quotient. It is a term used in biology to describe a specific ratio in the process of respiration.

2. **Definition of R.Q.:** 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 over a given period of time, under standard temperature and pressure conditions.

3. **Mathematical Representation:** Mathematically, R.Q. can be expressed as:
\[ R.Q. = \frac{\text{Volume of CO2 produced}}{\text{Volume of O2 consumed}} \]

4. **Variation with Substrate:** The value of R.Q. varies depending on the type of respiratory substrate being used. Different substrates (carbohydrates, proteins, and fats) yield different R.Q. values due to their distinct metabolic pathways.

5. **Examples of R.Q. Values:**
- For carbohydrates, the R.Q. is approximately 1.0.
- For proteins, the R.Q. ranges from 0.8 to 0.9.
- For fats, the R.Q. is about 0.7.

6. **Conclusion:** Since the R.Q. provides information about the type of substrate being utilized for respiration, it indicates the nature of the respiratory substrate.

**Final Answer:** R.Q. indicates the nature of the respiratory substrate.

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