Respiratory substrates

Respiratory quotient

CO₂ produced / O₂ consumed

What is the RQ of proteins?

0.9

What is the RQ of lipids?

0.7

Resoiratory substrate

any organic molecule broken down to release energy for the synthesis of ATP

Triglycerides as a respiratory substrate

glycerol is converted to pyruvate before undergoing oxidative decarboxylation, forming an acetyl group which is picked up by CoA, forming acetyl CoA

Proteins as a respiratory substrate (2 points)

first have to be hydrolysed and deaminated before they enter the respiratory pathway

these steps require ATP, reducing net production of ATP

Why is the RQ of carbohydrates 1?

it takes 6 O₂ molecules to completely respire 1 molecule of glucose, this results in the production of 6 CO₂ molecules

What is the RQ of carbohydrates?

1