A scientist investigated two plant hormones, P and Q.
In trial 1, dormant lettuce seeds were sprayed once with different concentrations of hormone P before they were sown.
| Concentration of P in spray solution in mg/dm³ | Seeds germinated after 5 days in % |
|---|---|
| 0 | 17 |
| 20 | 58 |
| 40 | 84 |
| 80 | 85 |
In trial 2, a fixed amount of hormone Q was released into separate closed rooms containing unripe plums. The rooms remained closed for 6 days.
| Initial concentration of Q in room in µL/dm³ | Plums ripe after 6 days in % |
|---|---|
| 0 | 9 |
| 10 | 51 |
| 30 | 88 |
| 60 | 89 |
Give the name of hormone P and the name of hormone Q.
The scientist wants to use the lowest concentration that gives a result within 2 percentage points of the highest result in each trial.
Give the concentration of P and the concentration of Q that the scientist should use.
In a repeat of trial 2, the door of each room was opened several times each day.
Suggest how this would affect the percentage of plums that were ripe after 6 days.
Suggest why opening the doors would have this effect.
87 exam-style questions on AQA GCSE Biology 5.4 Plant hormones, covering 5.4.1 Control and coordination and 5.4.2 Use of plant hormones (HT only). Each one has a worked solution and a mark scheme showing where the marks go.