Question

Respiratory Quotient (RQ) value of tripalmitin is
A. $0.9$
B. $0.7$
C. $0.07$
D. $0.09$

Answer 1

Hint:- The respiratory quotient, also called a respiratory coefficient, is a type of dimensionless number. It is used in calculations of the basal metabolic rate of the system. It is calculated from the ratio of carbon dioxide produced to oxygen consumed in respiration per unit time per unit weight at standard temperature and pressure. Its value ranges from $1$, $0$, $\geqslant 1$ to $\leqslant 1$

Complete Answer:- Tripalmitin is a type of triglyceride derived from the palmitic fatty acid. When the respiratory quotient is $1$ for carbohydrates are the respiratory substrate and the respiration is aerobic. The respiratory quotient is $\geqslant 1$ for organic acids acting as the respiratory substrate, near $0.7$when respiration is aerobic for fats this occurs during germination of fatty seeds, around $0.9$ for proteins and peptones. It is different for different respiratory substrates which are used during respiration and thus depends on the type of substrates.
When the respiratory substrate is Tripalmitin (fat),
Respiratory quotient = $RQ = \dfrac{{Volume\,of\,C{O_2}\,evolved}}{{Volume\,of\,{O_2}\,absorbed}}$
$2\left( {{C_{51}}{H_{98}}{O_6}} \right)\, + \,145{O_{2\,}}\, \to \,102C{O_{2\,}}\, + \,98{H_2}O$
Tripalmitin
$\therefore \,RQ = \,\dfrac{{102C{O_2}}}{{145{O_2}}}$ = 0.7

So, the correct option is (B) 0.7

Note:- RQ is $0$ for Succulents as no $C{O_2}$is evolved during the night (as the same is used in carbon fixation). RQ is $\geqslant 1$ in anaerobic respiration when there is no consumption of ${O_2}$and $C{O_2}$is produced in most of the cases. Therefore, the respiratory quotient is infinity ($\infty$)and carbohydrate is the usual substrate.