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2 marksIrritability and Response

CSEC Biology · January 2010 · Paper 2 · Question 1(d)(i)

The response to gravity shown by seedlings is due to uneven distribution of auxins. In experiments to demonstrate this response, the seedlings in the control are constantly rotated.

Why is this an important step in the investigation?

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Other parts of this question

  1. 1(a)In the space provided, produce a diagram to show how the apparatus in Figure 1 could have been set up for this investigation.[4 marks]
  2. 1(b)(i)Complete Table 1 by calculating the total and percentage of larvae on the dark side and the light side of the petri dish. Write your answer in Table 1.[2 marks]
  3. 1(b)(ii)Do the results of this investigation support the student's hypothesis? Give a reason for your answer.[2 marks]
  4. 1(b)(iii)Name TWO factors OTHER THAN light that could have influenced the larvae's response.[2 marks]
  5. 1(b)(iv)Describe how the apparatus shown in (a) could be modified to investigate ONE of the factors named in (b) (iii).[2 marks]
  6. 1(b)(v)Explain how the response shown by the larvae in this experiment could help them to survive in their natural environment.[2 marks]
  7. 1(c)(i)How does the response shown in Figure 2 benefit the plant?[2 marks]
  8. 1(c)(ii)Describe an experiment to determine whether a leaf on a potted plant has been photosynthesizing.[3 marks]
  9. 1(c)(iii)Name TWO conditions OTHER THAN light, that are necessary for photosynthesis.[2 marks]
  10. 1(d)(ii)Explain why the response to gravity is essential for plant survival.[2 marks]

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