Outline4 marksStandard
A student uses a simple respirometer to measure the oxygen uptake and carbon dioxide production of germinating wheat seeds over 24 hours. The results show that the volume of CO₂ produced is 2.8 cm³ and the volume of O₂ consumed is 2.8 cm³.
The student also has the following table of theoretical respiratory quotient (RQ) values for different substrates:
| Respiratory substrate | RQ |
|---|---|
| Carbohydrate | 1.0 |
| Lipid | ≈0.7 |
| Protein | ≈0.9 |
Outline how the student can use these results to determine the respiratory substrate being used, and outline the relative energy values of carbohydrates, lipids, and proteins as respiratory substrates.