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2 marksNutrition in Living Organisms

CSEC Biology · May/June 2016 · Paper 2 · Question 1(a)(vii)

Students investigate the effect of temperature on the rate of reaction of the enzyme, catalase. They use crushed potato as the source of the enzyme and place 5 mg into each of 7 test tubes. They add 3 cm³ of 1% hydrogen peroxide to each test tube and place them into water-baths kept at the following temperatures: 0 °C, 10 °C, 20 °C, 30 °C, 40 °C, 50 °C and 60 °C. They count the number of bubbles released per minute from each test tube and record the data in Table 1.

How could this experiment be modified to investigate the effect of pH on enzyme activity?

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Other parts of this question

  1. 1(a)(i)Plot a graph on the grid provided on page 5 to show the relationship between the number of oxygen bubbles released and temperature.[4 marks]
  2. 1(a)(ii)From your graph, determine the optimum temperature for the enzyme.[1 mark]
  3. 1(a)(iii)Explain the shape of the graph at EACH of the following temperature ranges: 0-10 °C, 11-40 °C, > 40 °C[6 marks]
  4. 1(a)(iv)Write a conclusion that the students could draw from their results.[1 mark]
  5. 1(a)(v)Suggest ONE reason why living organisms need to maintain a constant internal temperature.[1 mark]
  6. 1(a)(vi)Describe TWO precautions that the students should take when doing this experiment.[2 marks]
  7. 1(b)Name TWO enzymes that function in protein digestion and describe the role of EACH.[2 marks]
  8. 1(c)(i)Name TWO parts of the alimentary canal that are responsible for the mechanical digestion of food.[2 marks]
  9. 1(c)(ii)Give TWO reasons why mechanical digestion of food is important.[2 marks]
  10. 1(c)(iii)Explain the significance of chemical digestion of food.[2 marks]

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