Exam skills
What the paper asks you to do
- Predict growth direction from a stimulus
- Explain unequal growth using auxin
- Interpret controlled seedling experiments
Plant biology
Coordination and response in plants
Explain directional growth responses and how auxin distribution produces different root and shoot responses.5090 syllabus routeConcept · skill · exam language
What to know
Build the topic around four anchors.
- 01Phototropism
- 02Gravitropism
- 03Auxin in shoots and roots
- 04Adaptive value of growth responses
Common mistakes
Where marks disappear
- Calling a tropism movement from one place to another
- Assuming auxin has the same effect in roots and shoots
- Ignoring the direction of the stimulus
Structured practice
Answer these without looking back.
For each prompt, write the biological chain clearly enough that every mark-worthy link is visible.
- 01Predict a shoot response to one-sided light.
- 02Explain positive gravitropism in roots.
- 03Design a control for a tropism investigation.
Continue learning
Use the complete resource route.
Open the student materials, official syllabus or the next topic in sequence.
This independent teaching resource follows the Cambridge O Level Biology 5090 syllabus direction and is not endorsed by Cambridge International Education.