Final answer:
The respiratory quotient (RQ) is the ratio of CO₂ produced to O₂ consumed during metabolism, used to determine which fuel source the body is using. RQ values are approximately 1.0 for carbohydrates, 0.7 for fats, and 0.8 for proteins, with the formula RQ = Vc/Vo.
Step-by-step explanation:
The respiratory quotient (RQ) is a measure that represents the ratio of the volume of carbon dioxide (CO₂) produced to the volume of oxygen (O₂) consumed during metabolism. The RQ is useful for indicating which type of macronutrient (such as carbohydrates, fats, or proteins) is being utilized for energy by the body. For complete oxidation of these macronutrients, carbohydrates (CHO) require an equal amount of oxygen and produce an equal volume of CO₂, resulting in an RQ value of 1.0. Fats require more oxygen relative to CO₂ produced, leading to an RQ of about 0.7. Proteins also require more oxygen and yield an RQ of around 0.8. The formula for RQ is RQ = Vc/Vo, where Vc is the volume of CO₂ produced and Vo is the volume of O₂ consumed.