Respiratory Quotient:
R.Q. is the ratio of the volume of carbon dioxide released to the volume of oxygen taken in respiration and it is mathematically expressed as: R.Q.=VolumeofO2consumedVolumeofCO2evolved
The value of R.Q. varies with the substrate. Thus the measurement of R.Q. gives some idea of the nature of the substrate being respired in a particular tissue. R.Q. is usually measured by Ganong's respirometer. Anaerobic respiration: Respiration in the absence of O2 i.e. in anaerobic respiration, R.Q. value is infinity as O2 is not consumed. C6H12O6→Zymase2C2H5OH+2CO2+Energy R.Q.=VolumeofO2consumedVolumeofCO2evolved=02=Infinity