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2 marksCellular Respiration and ATP Synthesis

CAPE Biology Unit 2 · 2012 · Paper 2 · Question 1(b)(ii)

Figure 2 displays results of an experiment investigating if pyruvate supplements enhance aerobic performance of trained male cyclists undergoing aerobic cycling until exhaustion, showing whole-blood lactate and glucose concentrations measured at 15-minute intervals.

Account for the trend observed in blood lactate levels during the first 60 minutes of the cycling activity.

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Other parts of this question

  1. 1(a)(i)a)On Figure 1, use a labelled arrow to indicate the stages at which ATP is used and ADP released, including the number of molecules involved.[1.5 marks]
  2. 1(a)(i)b)On Figure 1, use a labelled arrow to indicate the stage at which NADPH is used and NADP+ released, including the number of molecules involved.[1.5 marks]
  3. 1(a)(ii)Outline the MAIN purpose of EACH of the three main phases of the Calvin cycle shown by the pie sections in Figure 1: - First phase - Second phase - Third phase[3 marks]
  4. 1(a)(iii)State ONE difference between the Calvin cycle and Krebs cycle (do NOT state the site of pathways as a difference).[2 marks]
  5. 1(b)(i)Describe the changes in blood lactate and glucose levels over the exercise period for cyclists who used pyruvate supplements.[4 marks]
  6. 1(b)(iii)Based on the data in Figure 2, suggest what conclusion may be drawn regarding the effect of pyruvate supplements on aerobic performance.[1 mark]

More practice: the rest of this paper · more Cellular Respiration and ATP Synthesis questions · all CAPE Biology Unit 2 past papers