CHIJ 2025 Sec 4E Biology Prelim Paper 2

O CONVENT OF THE HOLY INFANT JESUS SECONDARY Preliminary Examination in preparation for the General Certificate of Education Ordinary Level 2025 CANDIDATE NAME CLASS REGISTER NUMBER BIOLOGY Paper 2 Written Additional Materials: Nil 6093/02 3 September 2025 1 hour 45 minutes READ THESE INSTRUCTIONS FIRST Write your name, class and register number in the spaces provided on the work you hand in. Write in dark blue or black ink on both sides of the paper. You may use an HB pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, glue, correction fluid or correction tape. Section A Answer all questions. Write your answers in the spaces provide. Section B Answer one questions. 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. This document consists of 20 printed pages and 4 blank pages. [Turn over

2 CHIJSec/2025/OLevelPrelim/6093/02 Section A Answer all questions. 1 Fig. 1.1 shows part of the human circulatory system. Fig. 1.1 (a) Structure P is the main artery that brings blood from the heart to all parts of the body. State one structural adaptation of this blood vessel. ………………………………………………………………………………………………………... ……………………………………………………………………………………………………..[1] (b) State the letter of the blood vessel that has the lowest blood pressure. ……………….. [1]

3 [Turn over CHIJSec/2025/OLevelPrelim/6093/02 (c) Describe the pathway of blood flowing from the left lung to the left kidney. Identify any of the relevant labelled structures as shown in Fig. 1.1. Your answer need not include the valves involved. ……………………………………………………….……………...…………………………..…… ……………………………………………………….……………...……………………………….. ……………………………………………………….……………...……………………………..… ……………………………………………………….……………...……………………………..… ……………………………………………………….……………...…………………………..…… ……………………………………………………….……………...…………………………..…… ……………………………………………………….……………...……………………..………[4] (d) Explain how the composition of blood in vessel M is different from vessel L. ……………………………………………………….……………...……………………………..… ……………………………………………………….……………...……………………………….. ……………………………………………………….……………...……………………………….. ……………………………………………………….……………...……………………………..[2] (e) Fig. 1.2 shows a cross-section of a coronary artery in a healthy person and in a person with coronary heart disease. Fig. 1.2 Explain how this condition affects the heart muscle. ……………………………………………………….……………...……………………………….. ……………………………………………………….……………...……………………………….. ……………………………………………………….……………...……………………………..[2] [Total: 10] healthy coronary artery coronary artery with plaque buildup

4 CHIJSec/2025/OLevelPrelim/6093/02 2 A microbiologist collected bacteria from a restaurant kitchen which was suspected to be responsible for an outbreak of food poisoning. The microbiologist spread the bacteria on nutrient agar and let them reproduce to form colonies. The bacteria colonies were then transferred onto new nutrient agar that contained high concentrations of antibiotics S and T, as shown in Fig. 2.1. Fig. 2.1 sample of bacteria collected from kitchen, spread on an agar plate many bacterial colonies agar plate 1 incubated agar plate 4 with antibiotic T agar plate 2 with no antibiotic agar plate 3 with antibiotic S bacteria transferred to agar plate 5 bacteria transferred to agar plate 6 agar plate 5 with antibiotic S agar plate 6 with antibiotic T bacteria transferred to growth medium and incubated bacteria transferred from agar plate 1 to agar plates 2, 3, and 4 at same time

5 [Turn over CHIJSec/2025/OLevelPrelim/6093/02 (a) Explain the difference in appearance between plates 2 and 4. ……………………………………………………….……………...……………………………….. ……………………………………………………….……………...……………………………..[1] (b) Explain why many bacterial colonies were found on agar plates 5 and 6. ……………………………………………………….……………...……………………………..… ……………………………………………………….……………...…………………………..…… ……………………………………………………….……………...…………………………..…… ……………………………………………………….……………...……………………..………[2] (c) State one method to prevent the phenomenon in plates 5 and 6 from occurring with bacterial infections in our daily lives. ……………………………………………………….……………...…………………………..…… ……………………………………………………….……………...……………………..………[1] (d) The next month, the same kitchen had a second outbreak. This time the laboratory results established that diners suffered from viral gastroenteritis after consuming food cooked in this kitchen. Based on the investigations in Fig. 2.1, the restaurant owners recommended diners to obtain antibiotic T to help treat the infection. Explain why this is ineffective. ……………………………………………………….……………...……………………………..… ……………………………………………………….……………...…………………………..…… ……………………………………………………….……………...…………………………..…… ……………………………………………………….……………...……………………..………[2] [Total: 6]

6 CHIJSec/2025/OLevelPrelim/6093/02 3 Fig. 3.1 shows a transverse section of a leaf. Fig. 3.1 (a) Write the chemical equation for photosynthesis. ……………………………………………………….……………...……………………………[1] (b) Identify cell X, and explain how it is adapted for its function. ……………………………………………………….……………...……………………………… ……………………………………………………….……………...……………………………… ……………………………………………………….……………...……………………………… ……………………………………………………….……………...……………………………[3] X leaf hair on bottom surface of leaf

7 [Turn over CHIJSec/2025/OLevelPrelim/6093/02 (c) The student noticed that the plant in Fig. 3.1 wilted during hot afternoons but recovered in the evenings. Explain how the plant is able to recover from wilting in the evening. ……………………………………………………….……………...……………………………… ……………………………………………………….……………...……………………………… ……………………………………………………….……………...……………………………… ……………………………………………………….……………...……………………………… ……………………………………………………….……………...……………………………… ……………………………………………………….……………...……………………………[3] (d) The student hypothesised that cutting off the leaf hairs would help the plant conserve more water. Do you agree? Explain your answer. ……………………………………………………….……………...……………………………… ……………………………………………………….……………...……………………………… ……………………………………………………….……………...……………………………… ……………………………………………………….……………...……………………………… ……………………………………………………….……………...……………………………… ……………………………………………………….……………...……………………………[3] [Total: 10]

8 CHIJSec/2025/OLevelPrelim/6093/02 4 An ecologist is studying the warm freshwater ecosystem in Cambodia. Table 4.1 shows a part of her report on the ecosystem. Table 4.1 trophic level examples of organisms dry mass (g/m2) energy (kJ/m2) producers algae, aquatic plants 200 14 600 primary consumers snails, tadpoles, small fish 92 630 secondary consumers birds, frogs, insects, turtles 12 220 tertiary consumers fish, crocodiles 2 35 (a) The dry masses and energy content of the organisms at each trophic level was measured and recorded. State one advantage of analysing dry biomass over the counting of organisms’ numbers at each trophic level. ……………………………………………………….……………...………………………..……... ……………………………………………………….……..……...………………..……………[1] (b) For the ecosystem in Cambodia, sketch a pyramid of biomass labelled with trophic levels. [2] (c) In another study, the ecologist focuses on the turtle population. Data of energies associated with one turtle over a period of a year is recorded in Table 4.2. Table 4.2 energy associated with one turtle energy / kJ per year energy available to the turtle 20 935 energy in undigested waste 1065