Question 25 of 33
Q.What is Respiratory Quotient? What is the RQ value of organic acid (Malic acid)?
Tamil Nadu DgeTamil Nadu HSC First Year (DGE) Board 2024Subjective· 3mImportance★★★★★
76% · 25/33 Questions
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Start your 14-day free trial to unlock the full solution →The Respiratory Quotient is the ratio of CO2 released to O2 consumed in respiration; for malic acid, an organic acid substrate, this ratio works out to 1.33 (greater than 1).
Respiratory Quotient (RQ), also called Respiratory Coefficient, is defined as:
RQ = Volume of CO2 evolved / Volume of O2 consumed (during a given period of respiration)
The value of RQ depends on the chemical nature of the respiratory substrate being oxidised, because different substrates require different amounts of oxygen relative to the CO2 they yield on complete combustion:
- For carbohydrates (e.g., glucose), which are already fully oxygenated relative to carbon and hydrogen content, RQ = 1 (e.g., C6H12O6 + 6O2 → 6CO2 + 6H2O, giving 6/6 = 1).
- For fats/lipids, which contain relatively less oxygen and more hydrogen/carbon per molecule, more O2 is needed per CO2 released, so RQ < 1 (typically around 0.7). …
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