AQA Biology A-Level Paper 2 Specimen QP

1 Figure 1 shows the apparatus used for measuring the rate of oxygen consumption in aerobic respiration by seeds. For the first 10 minutes, the tap attached to tube A was left open and the syringe from tube B was removed. Suggest three reasons why the apparatus was left for 10 minutes. [3 marks] 1 2 3 3 uggest and explain why the chosen temperature was 20 °C for this experiment. [2 marks] Question 1 continues on the next page 4 After 10 minutes, the tap attached to tube A was closed and the syringe was attached to tube B. Every minute, the syringe plunger was moved until the levels in the U-tube were the same. The reading on the syringe volume scale was then recorded. The results are shown in Table 1. Table 1 Time / minutes Reading on syringe volume scale / cm3 0 0.84 1 0.81 2 0.79 3 0.76 4 0.73 5 0.70 6 0.68 7 0.66 8 0.63 9 0.62 10 0.58 During the experiment, the coloured liquid in the tubing moved towards tube B. Explain what caused this. [3 marks] [Extra space] 5 The mass of the seeds was 1.6 g. Use the information in Table 1 to calculate the rate of oxygen consumption in cm3 g–1 hour–1 by the seeds. Show your working. [2 marks] Rate = cm3 g–1 hour–1 Turn over for the next question 6 There are no questions printed on this page DO NOT WRITE ON THIS PAGE ANSWER IN THE SPACES PROVIDED 7 Describe the roles of calcium ions and ATP in the contraction of a myofibril. [5 marks] [Extra space] P is an energy source used in many cell processes. Give two ways in which ATP is a suitable energy source for cells to use. [2 marks] 1 2 8