Yeast is used to make bread. Yeast cells in bread dough respire anaerobically.
A student put equal masses of bread dough into measuring cylinders. The student kept each measuring cylinder at a different temperature and measured the increase in volume of the dough after 60 minutes.
The Table shows the results.
Table
| Temperature in ∘C^\circ\text{C}∘C | Increase in volume of dough in cm3\text{cm}^3cm3 |
|---|---|
| 15 | 12 |
| 25 | 30 |
| 35 | 54 |
| 45 | 20 |
Write the word equation for anaerobic respiration in yeast.
Explain why the volume of the dough increased.
Calculate the percentage increase in the volume gained by the dough when the temperature was raised from 25 ∘C25\ ^\circ\text{C}25 ∘C to 35 ∘C35\ ^\circ\text{C}35 ∘C.
Suggest why the increase in volume at 45 ∘C45\ ^\circ\text{C}45 ∘C was less than the increase in volume at 35 ∘C35\ ^\circ\text{C}35 ∘C.
42 exam-style questions on Edexcel GCSE Biology 8.3 Respiration, covering 8.3.1 Aerobic and anaerobic respiration. Each one has a worked solution and a mark scheme showing where the marks go.