Question

RQ in anaerobic respiration is?
A)07
B)0.9
C)Unity
D)Infinity

Answer 1

RQ is called the respiratory quotient which is defined as the ratio of $CO_2$ produced to $O_2$ consumed while the food is being metabolized. RQ= $CO_2$ eliminated divided by $O_2$ consumed.

Complete answer:
Most energy sources consist of carbon, hydrogen and oxygen. This includes fat, proteins, carbohydrates and ethanol. Upon their digestion, the ratio of $CO_2$ produced to $O_2$ consumed gives the respiratory quotient. Let us analyze the options to find out the correct option.

Option A: The chemical composition of fats differ from carbohydrates and their metabolism gives a respiratory quotient value of 0.7. Example of this is digestion of palmitic acid. Therefore, this is the incorrect option.

Option B: The RQ of proteins is 0.9. Example is oxidation of albumin. Therefore, this is the incorrect option.

Option C: The RQ of carbohydrates when they undergo aerobic respiration is unity or 1 as the amount of carbon dioxide produced is equal to amount of oxygen consumed. Therefore, this is the incorrect option.

Option D: In anaerobic respiration, oxygen is not consumed and carbon dioxide is released. This gives the RQ quotient to be infinite. This is explained by the equation $RQ$= $CO_2$ divided by $O_2$ = $\dfrac{2}{0}$ = Infinity. Therefore, this is the correct option.

Hence, the correct answer is option (D)

Note: Anaerobic metabolism of carbohydrates gives the RQ as infinity in which no oxygen molecule is consumed and two molecules of carbon dioxide are produced.