A student investigates the effect of exercise on breathing rate.
She counts her breathing rate at rest. She then does step-ups for 2 minutes and counts her breathing rate again.
The Table shows her results.
Table
| Time | Breathing rate in breaths per minute |
|---|---|
| at rest | 15 |
| straight after 2 minutes of step-ups | 28 |
| 1 minute after stopping | 22 |
| 3 minutes after stopping | 16 |
Calculate the percentage increase in breathing rate from rest to straight after the step-ups.
Give your answer to the nearest whole number.
Explain why the breathing rate increases during exercise.
The student wants to compare her results with a friend's results.
Give one variable they should keep the same so that the comparison is fair.
113 exam-style questions on OCR GCSE Biology 1.3 Respiration, covering 1.3.1 Cellular respiration supplies ATP, 1.3.2 Aerobic and anaerobic respiration, 1.3.3 Sugars and carbohydrates, 1.3.4 Amino acids and proteins, and 1.3.5 Fatty acids and lipids. Each one has a worked solution and a mark scheme showing where the marks go.