Question

Define RQ. What is its value for fats?

Answer 1

Part 1: Definition of respiratory quotient (RQ)
The ratio of the volume of CO2 evolved during the respiration of an organic substance to the volume of O2 consumed in respiration is called respiratory quotient (RQ).

Part 2: Formula
$RQ=\frac{\text{Volume of}C{O}_2}{\text{Volume of}{O}_2}$

Part 3: RQ value for fats
When fats are utilised in respiration, they consume more volume of oxygen than the amount of carbon dioxide evolved.
For example : $2\left(C_{31}{H}_{98}{O}_6\right)+145O_2\to 102C{O}_2+98H_{2}O+\text{Energy}$
$RQ=\frac{\text{102 molecules of}C{O}_2}{\text{145 molecules of}{O}_2}$ = 0.7 (less than unity)
Thus, the respiratory quotient of fats is less than 1.