Question

Respiratory quotient (R.) for fatty acid is

• A. > 1
• B. <1
• C. 1
• D. 0

Answer 1

The Correct Option is B

The respiratory quotient (RQ) is a useful measure in biology to determine the type of substrate being metabolized by an organism for energy. It is calculated as the ratio of carbon dioxide produced to oxygen consumed during metabolism:

RQ = \frac{\text{CO}_2 \text{ produced}}{\text{O}_2 \text{ consumed}}

The value of RQ varies depending on the type of substrate being metabolized:

• For carbohydrates, the RQ is typically 1, because the amount of oxygen consumed is equal to the carbon dioxide produced.
• For fats (fatty acids), the RQ is less than 1, typically around 0.7. This is because fats are rich in hydrogen and require more oxygen for complete oxidation compared to carbohydrates, resulting in a lower ratio of carbon dioxide production.
• For proteins, the RQ is usually between 0.8 and 0.9.

Therefore, for fatty acids, the respiratory quotient is less than 1. The correct answer is < 1.

Justification:

• > 1: This RQ value is generally associated with conditions such as lipogenesis (fat storage) where more carbon dioxide is produced than oxygen consumed, which does not apply to the direct metabolism of fatty acids.
• 1: This is typical for carbohydrates, not for fatty acids.
• 0: This would imply that no carbon dioxide is produced, which is not possible during metabolism of fatty acids.