2024 ADSS Prelim P2

This question paper consists of 18 printed pages including this cover page. ADMIRALTY SECONDARY SCHOOL SUBJECT : Biology CODE/PAPER : 6093/2 LEVEL/STREAM : Secondary 4 Express DATE : 22 August 2024 TIME : 0800h – 0945h DURATION : 1 hour 45 minutes READ THESE INSTRUCTIONS FIRST Write your name, class and register number on all the work you hand in. Write in dark blue or black pen. You may use an HB pencil for any diagrams, graphs, tables or rough working. Do not use staples, paper clips, glue or correction fluid. Section A Answer all questions. Write your answers in the spaces provided. Section B Answer one question. Write your answers in the spaces provided. The use of an approved scientific calculator is expected, where appropriate. The number of marks is given in brackets [ ] at the end of each question or part question. DO NOT TURN OVER THIS PAPER UNTIL YOU ARE TOLD TO DO SO. PRELIMINARY EXAMINATION 2024 For Examiner’s Use Section A / 70 Section B / 10 Total / 80 NAME: NO: CLASS:

2 Section A Answer all questions. 1 An experiment was set up to investigate the effect of different sodium chloride concentrations on the volume of animal cells. The final volume of the animal cells was compared with the original volume of animal cells and the results are shown in Fig. 1.1 Fig. 1.1 (a) With reference to Fig. 1.1, state the concentration of sodium chloride solution which has the same water potential inside the cells. Explain your answer. ………………………………………………………………………………….. ………………………………………………………………………………….. ………………………………………………………………………………….. [2] concentration of sodium chloride solution (mmol/dm3) ratio of final volume of cells to original volume of cells 0 10 20 30 40 50 60 70 80 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2

3 (b) Describe and explain the appearance of the animal cells placed in a concentration of sodium chloride solution of 40 mmol/dm3. …………………………………………………………………………………. …………………………………………………………………………………. …………………………………………………………………………………. [2] (c) (i) Predict an observation when these animal cells are placed in a concentration of sodium chloride solution less than 10 mmol/dm3. ……………………………………………………………………………. [1] (ii) Explain your answer in (c)(i). …………………………………………………………………………… …………………………………………………………………………… …………………………………………………………………………… [2]

4 2 In an experiment, four starch agar plates were prepared. Plates 1, 2 and 3 were treated with a filter paper disc soaked with liquid Y at different pH values. In plate 4, liquid Y was boiled and cooled before being placed on the agar starch as shown in Fig. 2.1. Fig. 2.1 The experiment set-ups were left for 30 minutes at 40 °C before iodine solution was added to each agar plate. The observations were recorded in Table 2.2. plate condition of liquid Y pH of liquid Y observation when tested with iodine solution 1 without boiled and cooled 3 blue-black only 2 without boiled and cooled 7 presence of brown patches 3 without boiled and cooled 9 blue-black only 4 boiled and cooled 7 blue-black only Table 2.2 (a) With reference to Fig. 2.1 and Table 2.2, state two conclusions that can be drawn and support your answer from the evidence of the experiment. Conclusion 1 …………………………………………………………………………………. Evidence from the experiment …………………………………………………………………………………. starch agar filter paper disc soaked with liquid Y

5 Conclusion 2 …………………………………………………………………………………. Evidence from the experiment …………………………………………………………………………………. [4] (b) Identify the part of the human body that liquid Y is produced naturally. …………………………………………………………………………………. [1] (c) Using the ‘lock -and-key’ hypothesis, explain the action of liquid Y on starch. …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… …………………………………………………………………………………… [3]

6 3 (a) Fig. 3.1 shows a section through the heart where a catheter is used to measure the pressure changes in the pulmonary artery. Fig. 3.2 shows the graph of pressure changes in the pulmonary artery. Fig. 3.1 Fig. 3.2 (i) State the part of the heart labelled X on Fig. 3.1. ………………………………………………………………………….. [1] (ii) There are three valves shown in Fig. 3.1 labelled 1, 2 and 3. State the valve(s) that will open at time A marked on the graph in Fig .3.2. ………………………………………………………………………….. [1] (iii) On Fig. 3.2, sketch and label a graph to show the expected pressure changes in aorta if it is measured at the same time. [1] (b) Balloon angioplasty is a m ethod to compress blockage in the artery due to fatty deposit so that the lumen in the artery can be enlarged again. The procedure is carried out as shown in Fig 3.3. Fig. 3.3 pressure time A aorta catheter pulmonary artery X 1 2 3 stage 1 artery wall balloon fatty deposit balloon inflated artery wall returning to its original shape stage 2 stage 3

7 (i) State a possible cause of occlusion in the artery. ………………………………………………………………………….. [1] (ii) Describe the structural characteristic of an artery wall when the balloon is inflated and removed for it to give rise to what is shown in stage 2 and 3. …………………………………………………………………………. …………………………………………………………………………. …………………………………………………………………………. [2] (iii) Explain what would happen in blood circulation if the artery wall does not have the characteristic mentioned in (b)(ii). ………………………………………………………………………….. ………………………………………………………………………….. ………………………………………………………………………….. [2] 4 (a) Define type 2 diabetes mellitus. ………………………………………………………………………………….. [1] (b) Identify one risk factor and one way to manage type 2 diabetes mellitus. ………………………………………………………………………………….. ………………………………………………………………………………….. ………………………………………………………………………………….. [2]

8 5 Fig. 5.1 shows a cross-section of a mammalian eye. Fig. 5.1 (a) State the structures labelled P, Q, R and S. P: …………………………….. Q: …………………………….. R: …………………………….. S: …………………………….. [2] (b) (i) When a person enters a dimly lit room from a bright environment, a pupil reflex occurs. Describe how structures R and S are involved in the pupil reflex. ………………………………………………………………………….. ………………………………………………………………………….. ………………………………………………………………………….. [2] (ii) Suggest why this reflex mentioned in (b)(i) is important. ………………………………………………………………………….. ………………………………………………………………………….. ………………………………………………………………………….. [2] (iii) State one other reflex action in the body. ………………………………………………………………………….. [1] S P Q R

9 (c) As a person ages, the vitreous humour liquefies and exerts an abnormal pull on the retina causing it to tear. The vitreous humour would seep through the tear and separate the retina from the tissue beneath it. Suggest why the seperation of the retina may cause blindness. ………………………………………………………………………………….. ………………………………………………………………………………….. ………………………………………………………………………………….. [2] 6 Haemoglobin is a large protein molecule found in red blood cells. The structure of each haemoglobin molecule is controlled by a gene that has two alleles: HbA codes for the normal form of haemoglobin HbS codes for the abnormal form of haemoglobin Red blood cells containing the abnormal form of haemoglobin became a stiff, sickle shape in conditions of low oxyge