Which of the following respiratory substrates yields a Respiratory Quotient (RQ) of approximately 0.9 during aerobic respiration?

Step-by-step solution

The Respiratory Quotient (RQ) is defined as the ratio of the volume of CO₂ evolved to the volume of O₂ consumed during respiration. For carbohydrates like glucose, the RQ is 1.0 . For fats and fatty acids, the RQ is less than 1 , typically around 0.7 . For proteins, the RQ is approximately 0.9 . For organic acids like malic acid, the RQ is greater than 1 (approximately 1.33 ). Therefore, proteins yield a Respiratory Quotient of approximately 0.9 . Answer: Proteins