Table 1 shows the mean mass-specific metabolic rate of two strains of Drosophila melanogaster (Strain X and Strain Y) at different ages.
| Age in days | Mean metabolic rate in μW mg−1\mu\text{W mg}^{-1}μW mg−1: Strain X | Mean metabolic rate in μW mg−1\mu\text{W mg}^{-1}μW mg−1: Strain Y |
|---|---|---|
| 5 | 32.5 | 28.4 |
| 15 | 27.2 | 24.1 |
| 25 | 22.8 | 20.6 |
| 35 | 19.4 | 17.5 |
| 45 | 15.6 | 13.2 |
Calculate the percentage decrease in the mean metabolic rate of Strain Y between 5 days and 45 days of age.
Use the equation:
percentage decrease=decrease in metabolic rateoriginal metabolic rate×100 \text{percentage decrease} = \frac{\text{decrease in metabolic rate}}{\text{original metabolic rate}} \times 100 percentage decrease=original metabolic ratedecrease in metabolic rate×100Give your answer to 3 significant figures.
51 exam-style questions on AQA GCSE Biology 4.2 Respiration, covering 4.2.1 Aerobic and anaerobic respiration, 4.2.2 Response to exercise, and 4.2.3 Metabolism. Each one has a worked solution and a mark scheme showing where the marks go.