CAIE IGCSE Biology 14.5.3 Gravitropism and Phototropism Questions
Practise designing and interpreting seedling investigations of root and shoot responses to gravity and directional light.
- Syllabus
- 2026–2028
- Course
- Biology 0610
Exam points
- describe root and shoot growth directions from seedling or Petri-dish results
- use darkness or uniform light to isolate a response to gravity
- explain that a rotating clinostat prevents gravity acting continuously on one side
CAIE IGCSE Biology 14.5.3 Gravitropism and Phototropism Questions question 1
A student investigated plant growth responses in roots and shoots. They used this method:
- Damp cotton wool was placed in two Petri dishes.
- Three bean seedlings were attached to the cotton wool in each Petri dish.
- Each seedling was orientated so that the roots pointed in a different direction in each Petri dish.
- Petri dish 1 was kept on its side in a fixed position.
- Petri dish 2 was kept on its side and rotated constantly.
- Both Petri dishes were kept in the dark.
- Both Petri dishes were kept in these conditions for two days.
- After two days the seedlings were observed.
Fig. 6.1 is a diagram of the apparatus.
Petri dish 1
Petri dish 2
Fig. 6.2 shows the seedlings after two days.
Fig. 6.2
Describe the pattern of growth of the bean roots and shoots in Petri dish 1 shown in Fig. 6.2.
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