Question

The respiratory quotient (RQ) of fats is:

• A. 1.0
• B. Greater than 1
• C. Less than 1
• D. 0

Hint:

RQ values: Carbohydrates = 1.0, Fats $\approx$ 0.7, Proteins $\approx$ 0.9.

Answer 1

The Correct Option is C

Step 1: Concept
The Respiratory Quotient (RQ) is the ratio of the volume of $CO_{2}$ evolved to the volume of $O_{2}$ consumed during respiration.

Step 2: Meaning
The RQ value depends on the type of respiratory substrate being oxidized.

Step 3: Analysis
Carbohydrates have an RQ of 1.0. Fats are oxygen-poor molecules compared to carbohydrates, so they require more external oxygen for complete oxidation, resulting in less $CO_{2}$ produced per $O_{2}$ molecule used.

Step 4: Conclusion
For most fats (like tripalmitin), the RQ value is approximately 0.7, which is clearly less than 1. Final Answer: (C)