Question

RQ (Respiratory Quotient) is defined as
A) Volume of $CO_2$ evolved=volume of $O_2$ consumed
B) Volume of $O_2$ consumed/volume of $CO_2$ evolved
C) Volume of $CO_2$ evolved/volume of $O_2$ consumed
D) Volume of $O_2$ evolved/volume of $CO_2$ consumed.

Answer 1

Hint: Respiratory quotient is a number used to calculate basal metabolic rate. It is measured using a respirometer. It acts as an indicator for overfeeding or underfeeding. It is also used to diagnose obstructive pulmonary diseases.

Complete answer:
The process in which the glucose is broken down by oxidation to release energy is called Respiration. During respiration, oxygen is used up by the cells and carbon dioxide is released as a by product. Respiratory Quotient is a process which measures how much oxygen is consumed and how much $CO_2$ is produced by the body in a given time.

The respiratory quotient can be represented as the volume of carbon dioxide evolved V/s the volume of oxygen consumed.

Significance of RQ- It indicates which molecules are being oxidised. For example if the value of RQ is 0.7, then lipids are metabolised. If the value of RQ is 0.8 then proteins are metabolised. For carbohydrates, the RQ is 1.

The factors which affect RQ are energy balance, circulating insulin and insulin sensitivity.

Hence the correct answer is option ‘C’ i.e, “volume of $CO_2$ evolved/volume of $O_2$ consumed”.

Note: RQ is used in the analysis of the functioning of several organs like liver and diagnosis of live diseases. The RQ serves as an indicator for predicting the survival rate in cases of liver cirrhosis patients. It also determines the disease severity in case of NFLD.