The respiratory quotient (RQ) of different respiratory substrates can be calculated using the formula:
RQ=Volume of carbon dioxide producedVolume of oxygen consumed\text{RQ} = \frac{\text{Volume of carbon dioxide produced}}{\text{Volume of oxygen consumed}}RQ=Volume of oxygen consumedVolume of carbon dioxide produced
The table below gives the standard RQ values for three pure respiratory substrates:
| Substrate | Standard RQ value |
|---|---|
| Carbohydrate | 1.0 |
| Protein | 0.8 |
| Lipid | 0.7 |
During an investigation into the respiration of a culture of germinating pea seeds, the following volumes of gases were recorded over a 24-hour period:
Calculate the RQ for this seed sample and suggest which combinations of respiratory substrates were being used.