Q7 / 180 · AIIMS 2014 · Botany
Assertion : Glucose is the favoured respiratory substrate.
Reason: When glucose is used as respiratory substrate and is completely oxidized, the RQ is 1 .
- Correct answerAIf both assertion and reason are true and reason is the correct explanation of assertion.
- BIf both assertion and reason are true but reason is not the correct explanation of assertion.
- CIf assertion is true but reason is false.
- DIf both assertion and reason are false.
Solution
(a): The ratio of the volume of $\mathrm{CO}_2$ evolved to the volume of $\mathrm{O}_2$ consumed in respiration is called the respiratory quotient (RQ) or respiratory ratio.
$\mathrm{RQ}=\frac{\text { Volume of } \mathrm{CO}_2 \text { evolved }}{\text { Volume of } \mathrm{O}_2 \text { consumed }}$
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 $\mathrm{CO}_2$ and $\mathrm{O}_2$ are evolved and consumed.
$\mathrm{C}_6 \mathrm{H}_{12} \mathrm{O}_6+6 \mathrm{O}_2 \longrightarrow 6 \mathrm{CO}_2+6 \mathrm{H}_2 \mathrm{O}+$ Energy
$\mathrm{RQ}=\frac{6 \mathrm{CO}_2}{6 \mathrm{O}_2}=1.0$
Hence, the correct answer is option: 'A'.