A germinating seed has an RQ of .7 most likely the substrate is

Options

A. Carbohydrate
B. Organic acid
C. Fats
D. Sugars

Answer

To determine the substrate used by a germinating seed with an RQ (Respiratory Quotient) of 0.7, we can follow these steps:

### Step-by-Step Solution:

1. **Understand RQ**: The Respiratory Quotient (RQ) is the ratio of the volume of carbon dioxide (CO2) produced to the volume of oxygen (O2) consumed during respiration. It is calculated using the formula:
\[ RQ = \frac{\text{Volume of CO2 evolved}}{\text{Volume of O2 consumed}} \]

2. **Identify RQ Values for Different Substrates**:
- Carbohydrates: RQ = 1.0
- Fats: RQ < 1.0 (typically around 0.7)
- Proteins: RQ ≈ 0.9
- Organic acids: RQ can vary but is generally not as low as 0.7.

3. **Analyze the Given RQ Value**: The problem states that the RQ of the germinating seed is 0.7. This value is indicative of fat metabolism, as it is lower than 1.0.

4. **Conclusion**: Since the RQ of 0.7 suggests that the primary substrate being utilized for respiration is fats, we conclude that the substrate is most likely fats.

### Final Answer:
The substrate is most likely **fats**.

---