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4 marksNutrition in Living Organisms

CSEC Biology · January 2009 · Paper 2 · Question 1(a)(i)

Students investigated the effect of pH on the activity of two digestive enzymes, X and Y, from different parts of the human digestive tract. Results are in Table 1.

Using the data in Table 1, complete the graph on page 3 to show the rate of reaction of Enzymes X and Y at the different pH levels.

This question uses a figure or table from the paper — you'll see it when you practise.

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Other parts of this question

  1. 1(a)(ii)Give ONE reason why the rate of reaction for both enzymes was sometimes zero.[1 mark]
  2. 1(a)(iii)a)What is the optimum pH for Enzyme X? What is the optimum pH for Enzyme Y?[6 marks]
  3. 1(a)(iii)b)Which enzyme functions at a lower pH range?[1 mark]
  4. 1(a)(iii)c)Which enzyme produces more products at its optimum pH?[1 mark]
  5. 1(a)(iii)d)Is it likely that Enzyme X and Enzyme Y are similar? Give ONE reason for your answer.[1 mark]
  6. 1(b)The product of reactions catalyzed by Enzymes X and Y is a reducing sugar. Describe a test the students could use to confirm the presence of the reducing…[5 marks]
  7. 1(c)(i)Although they are produced by different organs in the human digestive system, Enzymes X and Y break down the same nutrient in the body. Identify Enzymes X and…[2 marks]
  8. 1(c)(ii)Label the diagram in Figure 1 to show where Enzymes X and Y are found.[2 marks]
  9. 1(c)(iii)Suggest TWO advantages to humans of having two forms of the same enzyme.[2 marks]
  10. 1(d)(i)Identify ONE condition or circumstance when digestion of food takes place in a plant.[1 mark]
  11. 1(d)(ii)Name TWO inorganic substances (mineral elements) required by plants to make their food.[2 marks]

More practice: the rest of this paper · more Nutrition in Living Organisms questions · all CSEC Biology past papers