R.Q. stands for

Options

A. Resistance coefficient
B. Replicase concentration
C. Respiratory quotient
D. Reticular concentration

Answer

### Step-by-Step Solution:

1. **Identify the Meaning of R.Q.:**
- R.Q. stands for "Respiratory Quotient." It is a term used in the study of respiration in biological systems.

2. **Understand the Definition:**
- The Respiratory Quotient (RQ) is defined as the ratio of carbon dioxide (CO2) produced to oxygen (O2) consumed during respiration.

3. **Calculate RQ:**
- The formula for RQ is:
\[ RQ = \frac{\text{CO2 evolved}}{\text{O2 consumed}} \]
- This ratio helps in understanding the type of substrate being metabolized by the organism.

4. **Different RQ Values for Different Substrates:**
- Different substrates yield different RQ values:
- **Carbohydrates:** RQ = 1 (equal amounts of CO2 produced and O2 consumed)
- **Fats:** RQ = 0.7 (less CO2 produced compared to O2 consumed)
- **Proteins:** RQ = 0.8 (intermediate values)
- **Organic Acids:** RQ > 1 (more CO2 produced than O2 consumed)

5. **Evaluate the Options:**
- The options provided were:
- A) Resistance coefficient (incorrect, related to physics)
- B) Replicase concentration (incorrect, relates to genetics)
- C) Respiratory quotient (correct)
- D) Reticular concentration (incorrect, no such term exists)

6. **Conclusion:**
- Based on the definitions and explanations above, the correct answer is **C) Respiratory Quotient**.