Tag: respiration and energy transfer

When the RQ value is less than one for fats,  as fats consume more oxygen for respiration than carbohydrates.

The respiratory quotient (RQ) is the ratio of 
RQ = CO$ _{2}$ eliminated / O$ _{2}$ consumed.
When carbohydrates are being oxidized in the organism and the requisite oxygen is available, the RQ is 1. In the oxidation of fats, the RQ is 0.7 and in the oxidation of proteins, 0.8. Whenever the substrate is protein, RQ is always less than one (0.5-0.9). So, in germinating seeds, when protein is aerobically oxidized, the R.Q value will be less than one. Thus, option A is correct and other options are incorrect.

The urge to breathe comes from the respiratory center, located at the base of brain. It sends signals via the spinal cord to diaphragm and the muscles between ribs telling them when to contract or relax. During inspiration, the diaphragm -- the large muscle that divides chest and abdomen -- contracts and moves downward. Additionally, ribs move outward. This enlarges your chest and lungs expand. Lung expansion creates a vacuum. Air enters the nose and mouth and is pulled into windpipe -- the trachea. The trachea divides into smaller airways called bronchi. These continue to divide as they get farther from the trachea, like the branches of a tree. Finally, the tiny airways deliver the air to the smallest structures in your lung -- the alveoli -- where gas exchange takes place.

The respiratory quotient (RQ) is the ratio of CO$ _{2}$ produced to O$ _{2}$ consumed while food is being metabolized.
RQ = CO$ _{2}$ eliminated/O$ _{2}$ consumed.
The respiratory quotient for carbohydrate metabolism can be demonstrated by the chemical equation for oxidation of glucose.
C$ _{6}$H$ _{12}$O$ _{6}$ + 6 O$ _{2}$ 6 CO$ _{2}$+ 6 H$ _{2}$O
Because the gas exchange in this reaction is equal, the respiratory quotient for carbohydrates is: RQ = 6 CO2 / 6 O2 = 1. Thus, option A is wrong.
The chemical composition of fats differs from that of carbohydrates in that fats contain considerably fewer oxygen atoms in proportion to atoms of carbon and hydrogen. The substrate utilization of palmitic acid is:
C$ _{16}$H$ _{32}$O$ _{2}$ + 23 O$ _{2}$ 16 CO$ _{2}$ + 16 H$ _{2}$O
Thus, the RQ for palmitic acid is approximately 0.7. RQ = 16 CO$ _{2}$ / 23 O$ _{2}$ = 0.696. Thus, option B is wrong.
The respiratory quotient for protein metabolism can be demonstrated by the chemical equation for oxidation of albumin:
C$ _{72}$H$ _{11}$2N$ _{18}$O$ _{2}$S + 77 O$ _{2}$ 63 CO$ _{2}$ + 38 H$ _{2}$O + SO$ _{3}$ + 9 CO(NH$ _{2}$)2
The RQ for protein is approximately 0.8. RQ = 63 CO$ _{2}$/ 77O$ _{2}$ = 0.8. Thus, option C is wrong.
In case of organic fats, volume of CO$ _{2}$ given out during respiration is more than the volume of O$ _{2}$ used. Thus, option D is correct.

RQ value = volume of CO$ _2$ evolved/volume of O$ _2$ consumed.

The utilization of oxygen is nill in anaerobic respiration. Hence the R.Q. value is infinity. 

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 over a period of time is called as respiratory quotient (RQ) or respiratory ratio.
$RQ=\frac{Volume\,\, of\,\, {CO} _{2} \,\,evolved}{Volume \,\,of \,\,{O} _{2} \,\,consumed}$.

The various organic substances such as carbohydrates, fats and proteins are respired completely to carbon dioxide and water are called respiratory substrates. Under natural conditions only carbohydrates are used. Glucose being the simplest monosaccharide hexose molecule acts as the chief respiratory substrate. 

The compensation point is the light intensity on the light curve for which the rate of photosynthesis is equal to the rate of respiration in the plant cell i.e., the rate of cellular fixation of Carbon dioxide through photosynthetic pathway is equal to the respiratory release of Carbon-dioxide and the release of Oxygen by photosynthesis is equals to the rate of consumption by respiration in a plant cell. At the compensation point, the organism is not building any biomass nor consuming any biomass.