A volunteer repeatedly squeezed a hand-grip sensor as hard as possible for 4 minutes.
The table shows measurements taken during the first 10 seconds and the final 10 seconds of the exercise.
| Measurement | First 10 seconds | Final 10 seconds |
|---|---|---|
| Heart rate in beats per minute | 80 | 140 |
| Breathing rate in breaths per minute | 16 | 32 |
| Mean grip force in N | 300 | 210 |
Calculate the percentage increase in the volunteer's heart rate.
Explain how the change in breathing rate helps the muscle cells continue contracting.
The volunteer continued to squeeze as hard as possible. Explain how anaerobic respiration contributed to the decrease in mean grip force.
92 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.