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Biology µGCSE:

Plant Responses (+ tropisms)

10 quick questions - for GCSE and iGCSE



10 minutes maximum! (can you do it in 5?)

1+2: This plant is growing towards the light.

plant growing towards light

1. This response is called ...
  • A. photosynthesis
  • B. positive phototropism
  • C. negative phototropism
  • D. transpiration
2. The stimulus for this response is ...
  • A. the intensity of the light
  • B. the wavelength of the light
  • C. the direction of the light
  • D. gravity

3-5: Experiments were carried out on 30 coleoptiles as in the diagrams. 10 were left untouched. 10 had their tips removed and 10 had their tips covered with foil caps.
The coleoptiles were left for 24 hours with light from one side.

plant growing towards light

3. Why were 10 coleoptiles used for each experiment?
  • A. To get accurate results
  • B. To get reliable data
  • C. The students enjoyed putting metal caps on the coleoptiles.
  • D. In case someone turned off the light
4. Which pair of experiments show that there is something in the shoot tip that controls the growth of the coleoptile?
  • A. L and M
  • B. L and N
  • C. M and N
  • D. K and L
5. Which pair of experiments show that it is the shoot tip that is the receptor for the direction of the light?
  • A. L and M
  • B. L and N
  • C. M and N
  • D. K and L

6.  The chemicals that are involved in the growth response of the plant are called auxins.

When plants bend towards unidirectional light ...

  • A. there is more auxin on the side nearest the light
  • B. there is more auxin on the side away from the light
  • C. there is no difference in the amounts of auxin on the two sides
  • D. all the auxin disappears
7. A seed was planted in the ground and a seedling has grown from that seed.

seed growing


7. When in the soil the shoot is ...

  • A. negatively phototropic
  • B. positively geotropic
  • C. negatively geotropic
  • D. positively hydrotropic
8. The stimulus that makes the new roots on a seedling grow downwards is ...
  • A. light
  • B. water
  • C. heat
  • D. gravity
9. Which of the following is not true?
  • A. Positive geotropism in roots means it does not matter which way up a seed is planted
  • B. Negative geotropism in shoots means shoots will always grow upwards towards light
  • C. Positive phototropism in roots means roots will always grow away from the light
  • D. Positive phototropism in shoots means shoots grow towards the light which they need for photosynthesis.
10. Auxins are used commercially by plant growers. Which of the following is not a use of auxins?
  • A. Weed killer¬†
  • B. Rooting powder for use on plant cuttings
  • C. Promoting growth of cells in tissue culture
  • D. Slowing the rate of photosynthesis