Respiratory Quotient & RQ Values — NEET Biology
✅ Asked in NEET 20262(C51H98O6) + 145 O2 -> 102 CO2 + 98 H2O + energy. The Respiratory Quotient (RQ) of the biomolecule used would be:
2(C51H98O6) + 145 O2 -> 102 CO2 + 98 H2O + energy. The Respiratory Quotient (RQ) of the biomolecule used would be:
Answer & NCERT explanation
Correct answer: A — Between 0.5 and 0.95
RQ = volume of CO2 evolved / volume of O2 consumed = 102/145 = 0.7. This corresponds to a fat (lipid) substrate and lies between 0.5 and 0.95.
Read more NCERT concept on the PYQ
Let us now look at another aspect of respiration. As you know, 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 is called the respiratory quotient (RQ) or respiratory ratio.
The respiratory quotient (RQ) is the ratio of CO2 released to O2 consumed during aerobic respiration. NTA tests whether students can calculate RQ for different substrates: carbohydrates have RQ = 1, fats have RQ = 0.7, and proteins have RQ = 0.9. Students often confuse RQ with the actual volumes consumed or produced, rather than treating it as a ratio. The key is remembering that RQ varies based on what substrate is being respired—carbs give complete oxidation (1:1 ratio), while fats require more oxygen (lower RQ). This concept frequently appears in questions about substrate metabolism and anaerobic conditions.
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Through deep analysis of NEET and NTA, 88 of 90 questions from the NEET 2026 paper were matched straight from the MedicNEET Biology question bank.
88/90MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.