Test: The Respiratory Balance Sheet Amphibolic Pathway & Respiratory Quotient (July 7) - NEET MCQ

The respiratory quotient (RQ) is used in calculations of basal metabolic rate (BMR). It is the ratio of the volume of carbon dioxide produced by the body to the volume of oxygen consumed by the body in respiration over a period of time. It depends on the type of respiratory substrate used during respiration. RQ of fat is about 0.7. RQ of carbohydrate is 1. RQ of organic acids is above 1. RQ of protein is 0.9. RQ value gives information about the source of energy an animal is using.
Thus, the correct answer is option A.

The electron transport chain along with oxidative phosphorylation involves the synthesis of energy-rich ATP molecules with the help of energy released during the oxidation of reduced coenzymes (NADH₂ and FADH₂) formed during glycolysis and the Krebs cycle. A total of 10 NADH₂ and 2 FADH₂ molecules are produced during aerobic respiration. They help in the formation of 32 ATP molecules.

Respiration is an oxidative process in which repiratory substrates are oxidised to liberate energy inside the living cells. The common respiratory substrates are carbohydrates, proteins, fats and organic acids. The most common respiratory substrates are carbohydrates, proteins, fats and organic acids. The most common respiratory substrate is glucose.

During aerobic respiration O₂ is consumed and CO₂ is released. The ratio of the volume of CO₂ evolved to the volume of O₂ consumed in respiration over a period of time is called as respiratory quotient (RQ) or respiratory ratio.

The respiratory quotient depends upon the type of respiratory substrate used during respiration.

(i) When carbohydrates are used as substrate and are completely oxidized the RQ will be 1, because equal amounts of CO₂ and O₂ are evolved and consumed respectively.

(ii) When proteins are respiratory substrates, the ratio would be about 0.9.

RQ slightly more than unity is found when organic acids are broken down as respiratory substrates under aerobic conditions, e.g., for breakdown of oxalic acid,

Succulents do not evolve carbon dioxide during the night (when their stomata are open) as the same is in carbon fixation. They also change carbohydrates to organic acids which utilise oxygen but do not evolve carbon dioxide.

In anaerobic respiration, there is no consumption of oxygen and carbon dioxide is produced in most of the cases. Therefore, respiratory quotient is infinity. Carb the usual substarte.

Glucose is a monomer that after ingestion, does not gets digested and directly gets absorbed and converted into energy. Therefore, glucose is an instantaneous source of energy.
Protein, fats, and nucleic acid don't get directly converted into energy. So, they are not the instantaneous source of energy. 

Aerobic respiration is a chemical reaction in which glucose gets oxidise and converted into carbon dioxide and water. The following is the balanced chemical reaction -
C₆H₁₂O₆ ​+ 6O₂ ​→ 6CO₂ ​+ 6H₂O + Energy.