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=Volume of CO2Volume of O2
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(C31H98O6)+145O2→ 102CO2+98H2O+Energy
RQ=102 molecules of CO2145 molecules of O2 = 0.7 (less than unity)
Thus, the respiratory quotient of fats is less than 1.