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6 marksNutrition in Living Organisms

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

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.

What is the optimum pH for Enzyme X? What is the optimum pH for Enzyme Y?

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Other parts of this question

  1. 1(a)(i)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.[4 marks]
  2. 1(a)(ii)Give ONE reason why the rate of reaction for both enzymes was sometimes zero.[1 mark]
  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