XMSS 2025 4E Bio Prelim Paper 2

This document consists of 22 printed pages. Preliminary Examination 2025 CANDIDATE NAME CLASS INDEX NUMBER BIOLOGY Paper 2 Secondary 4 Express Setter: Mdm Norfarhana Vetter: Ms Noor Hafizah 6093/02 25 August 2025 1 hour 45 minutes Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your name, class and index number on the work you hand in. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. 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. For Examiner’s Use Section A 70 Section B Q ………. 10 Total 80 Parent’s Signature [Turn over

2 XMSS/Biology/6093/02/ Preliminary Examination 2025 Section A [70 marks] Answer all questions. Write your answers in the spaces provided. 1 Two samples of blood were mixed with equal volumes of different liquids. A drop of each mixture was put on a slide and examined with a light microscope. Table 1.1 describes the appearance of each slide when viewed under the microscope. Table 1.1 slide liquid added appearance of slide A distilled water No cells seen. A uniform pale red solution was seen. B sucrose solution Cells are smaller in diameter than in an untreated sample of blood. (a) Explain the appearance of slide A. …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… [3] (b) State the term used to describe the condition of cells on slide B. …………………………………………………..………………………………………. [1]

3 XMSS/Biology/6093/02/ Preliminary Examination 2025 (c) Fig 1.1 shows red blood cells from a chicken as seen under a light microscope. Fig. 1.1 (i) Chicken red blood cells contain a structure that is not found in human red blood cells. Identify this structure. ……………………………………………………………………………………. [1] (ii) Explain how the adaptation in (c)(i) allows human red blood cells to function effectively. ……………………………………………………………………………………. ……………………………………………………………………………………. ……………………………………………………………………………………. ……………………………………………………………………………………. [2] [Total: 7] [Turn over

4 XMSS/Biology/6093/02/ Preliminary Examination 2025 2 A group of scientists wanted to investigate the effect of a n 11% bile salt solution on the digestion of fats by lipase. Fig. 2.1 shows their results. Fig. 2.1 (a) Describe and explain the results shown in Fig. 2.1. …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… [3] (b) (i) Sketch a graph on Fig. 2.1 to show the effect if the lipase is boiled first before the experiment. [1] (ii) Explain your graph in (b)(i). ……………………………………………………………………………………. ……………………………………………………………………………………. ……………………………………………………………………………………. ……………………………………………………………………………………. [2] 0 15 30 45 60 9.5 9.0 8.5 8.0 7.5 7.0 6.5 6.0 lipase with no bile solution lipase with 11% bile salt solution pH of solution time / minutes

5 XMSS/Biology/6093/02/ Preliminary Examination 2025 Fig. 2.2 shows an electron micrograph of the pancreatic cell that secretes the enzyme lipase into the alimentary canal. Fig. 2.2 (c) Describe how structures E, F and G are involved in the synthesis of lipase for secretion into the alimentary canal. …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… [4] [Total: 10] secretory vesicles E F vacuole G [Turn over

6 XMSS/Biology/6093/02/ Preliminary Examination 2025 3 An optometrist tested a patient’s eyesight. One of the tests performed by the optometrist was a field test. This test examines the sensitivity of the patient’s retina to light in different areas of the field of vision. The field test on the patient was carried out as follows: • With one eye covered, the patient stared at the centre of a screen. • Points of light of varying intensities then appeared briefly on the screen, each in a different area, J, K or L, of the patient’s field of vision. • Each time the patient saw a point of light, she pressed a button to record this using an event-recorder. Table 3.1 shows the results for one of the patient’s eyes, which fall within the expected range of a healthy person. Each of the areas J, K and L of the patient’s field of vision corresponds to an area on her retina shown in Fig. 3.2. Table 3.1 intensity of point of light / arbitrary unit number of times out of 5 tries that the patient detected point of light area J area K area L 1 (dim) 2 0 0 2 3 2 0 3 4 4 0 4 (bright) 4 5 0 Fig.3.2 K J L

7 XMSS/Biology/6093/02/ Preliminary Examination 2025 (a) Explain the results for area L. …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… [2] (b) There are two types of photoreceptors in the retina, cone cells and rod cells. Cone cells are important for colour vision and are less sensitive to light. Rod cells are important for detecting movements and are very sensitive to light. State the conclusions that can be made about the relative distribution of cone and rod cells in areas J and K. Explain your answer. …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… [2] (c) As the light intensity increases during the experiment, the diameter of the pupil also changes. Describe the nervous pathway that causes the change in the diameter of the pupil during the experiment. …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… …………………………………………………………………………………………… [5] [Total: 9] [Turn over

8 XMSS/Biology/6093/02/ Preliminary Examination 2025 4 The following experiment was carried out to investigate the effect of light intensity on the rate of photosynthesis of a water plant, Elodea. • Elodea was cut into three pieces, each 10 cm long. • Each piece of Elodea was placed in a glass tube, containing 0.5% sodium hydrogen carbonate solution, which was then sealed with a bung. • Tube A was placed 10 cm away from a lamp. • Tube B was placed 5 cm away from a lamp. • Tube C was placed in a dark room. • An oxygen sensor was used to measure the percentage of oxygen in t