Question

Different substrates get oxidized during respiration. How does Respiratory Quotient (RQ) indicate which type of substrate, i.e., carbohydrate, fat or protein is getting oxidized?

`R.Q. = A/B`

What do A and B stand for?
What type of substrates have R.Q. of 1, < 1 or > 1?

Answer 1

Respiratory Quotient (RQ) indicates which type of substrate, i.e., carbohydrate, fat or protein is getting oxidized by measuring the volume of carbon dioxide, i.e., CO₂ released or evolved by the volume of oxygen O₂ consumed.

A = Volume of CO₂ released

B = Volume of Oxygen consumed

RQ equal to 1 = Carbohydrates like glucose.

RQ higher than 1 = Substrate can be organic acid like malic acid.