Tag: respiration and energy transfer

Respiratory quotient or R.Q is defined as the ratio of carbon dioxide evolved to oxygen taken in for respiratory break down of a substrate. The value of R.Q for oxidation of carbohydrates is unity and less than one for oxidation of fats and proteins. Thus if groundnut, which stores fats is used as respiratory substrate the value of R.Q will be less than one.

During aerobic respiration, $O _2$ is consumed and $CO _2$ is released. The ratio of the volume of $CO _2$ evolved to the volume of $O _2$ consumed in respiration is called the respiratory quotient (RQ) or respiratory ratio. Thus the following expression is used to calculate the value of 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. When carbohydrates are used as substrate and are completely oxidised, the RQ will be 1, because equal amounts of $CO _2$ and $O _2$ are evolved and consumed, respectively. When fats are used in respiration, the RQ is less than 1. When proteins are respiratory substrates the ratio would be about 0.9.
Under conditions of starvation carbohydrates are not available and proteins or fats are used as cellular fuel and hence the expected value of RQ is less than unity.

R.Q. is the ratio of carbon dioxide evolved and the oxygen consumed during the process of respiration.

In succulent plants at night the stomata are open and carbon dioxide is fixed into organic acids. Thus at night there is no net carbon dioxide evolved. Hence, value of RQ is zero.

The respiratory quotient depends upon the type of respiratory substrate used during respiration. When fats are used in respiration, the RQ is less than 1. Groundnut and  castor seeds are fats storing seeds, the stored fats are mobilised during their seed germination. Hence, the RQ value is less than one for germinating groundnut and castor seeds.

R.Q. is the ratio of the volume of carbon dioxide evolved and oxygen consumed in respiration.

During aerobic respiration, $O _2$ is consumed and $CO _2$ is released. The ratio of the volume of $CO _2$ evolved to the volume of $O _2$ consumed in respiration is called the respiratory quotient (RQ) or respiratory ratio. Thus the following expression is used to calculate the value of RQ.
RQ= volume of $CO _2$ evolved/ volume of $O _2$ consumed.
At compensation point there is no net evolution of carbon dioxide. Hence, numerator in above expression is zero, giving the value of RQ as zero.

During the ripening of oil-seeds, when fats are formed from carbohydrates the respiratory quotient is greater than 1. This arises because part of the oxygen consumed in respiration is derived from carbohydrates.

During aerobic respiration, O$ _2$ is consumed and CO$ _2$ is released. The ratio of the volume of CO$ _2$ evolved to the volume of O$ _2$ consumed in respiration is called as the respiratory quotient (RQ) or respiratory ratio. Thus, the following expression is used to calculate the value of RQ.
RQ = volume of CO$ _2$ evolved/ volume of O$ _2$ consumed.
In an actively photosynthesizing tissue, the net volume of carbon dioxide evolved (i.e., volume of carbon dioxide produced in respiration minus that utilised in photosynthesis) is equal to net volume of oxygen (i.e., volume of oxygen consumed in respiration minus that evolved in photosynthesis). 

The respiratory quotient depends upon the type of respiratory substrate used during respiration. When organic acids are metabolised more carbon dioxide is evolved than oxygen consumed. Hence, the value of RQ is more than one.