Question

If R.Q. is 0.6 in respiratory metabolism, it would mean that
(a) Carbohydrates are used as a respiratory substrate
(b) Organic acids are used as a respiratory substrate
(c) The oxidation of the respiratory substrate consumed more oxygen than the amount of $\mathrm{CO_2}$ released
(d) All of the above

Answer 1

Hint: The respiratory quotient (RQ) measures the ratio of the volume of carbon dioxide (Vc) produced by an organism to the volume of oxygen consumed (Vo) by that organism. The respiratory quotient (RQ) is used in the calculations of the basal metabolic rate (BMR).

Complete answer:
-If R.Q.is 0.6 in respiratory metabolism, it means that the oxidation of the respiratory substrate consumed more oxygen than the amount of ${CO}_{2}$ released.
-The respiratory quotient (RQ) is the ratio:
RQ =${CO}_{2}$eliminated /${O}_{2}$consumed
-From the formula, we know that the higher the amount of ${CO}_{2}$released, the higher the value of R.Q., the higher the amount of ${O}_{2}$ consumed, lesser the value of R.Q.
-The value of respiratory quotient for the oxidation of carbohydrates is unity and less than one for the oxidation of fats and proteins.
Additional Information
-Respiration is the process by which we break down the carbon-carbon bonds with the help of oxidation which releases a great amount of energy.
-It is of two types Aerobic (presence of oxygen) and anaerobic (absence of oxygen).
-In higher animals it occurs in the mitochondria hence known as the ‘PowerHouse of the Cell’.
-Fermentation is an example of anaerobic respiration in which partial oxidation of substrate occurs and alcohol is released,

So, the correct answer is, ‘The oxidation of the respiratory substrate consumed more oxygen than the amount of ${CO}_{2}$ released.’

Note:
-The respiratory quotient (RQ) is used in the calculations of the basal metabolic rate (BMR).
-It depends on the type of respiratory substrate used during respiration.
-RQ of fat is about 0.7, carbohydrate is 1 and that of organic acid is above 1.