Define RQ. Write a short note on RQ.

Explanation

The ratio of the volume of `CO_2` evolved to the volume of `O_(2)` cosumed in respiration is called the Respiratory Quotient (RQ).
RQ = `("Volume of " CO_(2) "evolved")/("Volume of " O_(2) "consumed")`
The respiratory quotient depends upon the type of respiratory substrate used during respiration.
1) When carbohydrates are used as substrate, the RQ is 1, because equal amounts of `CO_2` and `O_(2)` are evolved and consumed.
Ex: `C_(6)H_(12) O_(6) + 6O_(2) to 6CO_(2) + 6H_(2)O +` Energy
`RQ = (6 CO_(2))/(6 O_(2)) = 1.0`
2) When fats are used in respiration the RQ is less than 1.
Ex : `2(C_(51) H_(98) O_(6)) + 145 O_(2) to 1 O_(2) CO_(2) + 98 H_(2)O` + Energy
`RQ = (102 CO_(2))/(145 O_(2)) = 0.7`
3) When protein are respiratory substrates the ratio would be about 0.9