TKGS Prelim paper 2

Tanjong Katong Girls’ School 1 Sec 4 Preliminary Examination 2025 TANJONG KATONG GIRLS’ SCHOOL PRELIMINARY EXAMINATION SECONDARY FOUR EXPRESS BIOLOGY CANDIDATE NAME CLASS INDEX NUMBER BIOLOGY 6093/02 Paper 2 18 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 register number on all the work you hand in. Write in dark blue or black pen. You may use a HB pencil for any diagrams, graphs 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. For Examiner’s Use Section A Section B Total / 80 This document consists of 22 printed pages.

Tanjong Katong Girls’ School 2 Sec 4 Preliminary Examination 2025 Section A Answer all questions. 1 A student investigates the uptake of potassium ions by root tissue. A root is cut into four discs of uniform size. Each disc is added to an equal volume of a solution containing a fixed potassium ion concentration. The experiment is carried out in different oxygen concentrations. The results are shown in Table 1.1. Table 1.1 oxygen concentration / arbitrary units 0 4 11 20 rate of potassium ion uptake / arbitrary units 7 27 92 100 (a) State, with a reason, one other variable that should be kept constant. …………………………………………………………………………………………….. …………………………………………………………………………………………….. …………………………………………………………………………………………. [2] (b) Using the information in Table 1.1, state and explain the main method by which potassium ions are taken into the root. …………………………………………………………………………………………….. …………………………………………………………………………………………….. …………………………………………………………………………………………….. …………………………………………………………………………………………….. …………………………………………………………………………………………. [3]

Tanjong Katong Girls’ School 3 Sec 4 Preliminary Examination 2025 (c) Suggest why the investigation uses four discs from one root tissue instead of one disc each from four root tissues. …………………………………………………………………………………………….. …………………………………………………………………………………………….. …………………………………………………………………………………………. [2] (d) The tissue given 0 arbitrary units of oxygen is then placed in concentrated sucrose solution. Complete Fig. 1.1 which shows the cell wall to show the appearance of the cell after 30 minutes. Label the nucleus and cytoplasm. Fig. 1.1 [2] [Total: 9]

Tanjong Katong Girls’ School 4 Sec 4 Preliminary Examination 2025 2 (a) State a metabolic waste product removed by the kidneys. ……………………….………………………………………………………………... [1] (b) Describe and explain the difference in water potential of glomerular filtrate and urine. ……………………………….……………………………………………………………. ………………………………….…………………………………………………………. …………………………………….………………………………………………………. ………………………………………….…………………………………………………. .……………………………………………………………………………………….... [3] (c) Glomerulonephritis is a type of kidney disease. It involves damage to the glomeruli in the kidneys. One of the symptoms of glomerulonephritis is foamy urine caused by the presence of proteins in the urine. (i) Explain how proteins end up in the urine. ………………………………………………………………………………………. ………………………………………………………………………………………. …………………………………………………………………………………... [2] (ii) State the elements and basic units contained in proteins. elements …………………………………………………………………………… basic units ……………..………………………………………………………. [2] [Total: 8]

Tanjong Katong Girls’ School 5 Sec 4 Preliminary Examination 2025 3 Fig. 3.1 shows the stem of the Myrmecodia plant. It has a symbiotic relationship with ants in which both types of organisms benefit from the other. The stem of the plant has many chambers which the ants live in. The ants collect the nectar from the flowers and carry it to the chambers. The chambers contain faeces produced by the ants and structures that absorb nutrients for the plants. Faeces of ants contain proteins. Fig. 3.1 (a) Explain how faeces produced by ants can be used by the plant for growth. …………………………………………….………………………………………………. …………………………………………….………………………………………………. ……………………………………………….……………………………………………. ………………………………………………….…………………………………………. ………………………………………………….…………………………………………. ……………………………………………………….………………………………... [3] openings of chambers chambers opening of chamber

Tanjong Katong Girls’ School 6 Sec 4 Preliminary Examination 2025 (b) State whether the environment in which the plant is growing i s nutrient-rich or poor. ……………………………………………………….………………………………... [1] (c) Describe how ants obtain raw materials to carry out aerobic respiration. ………………………….…………………………………………………………………. ……………………………….……………………………………………………………. …………………………………….………………………………………………………. ……………………………………….………………………………………………... [2] [Total: 6]

Tanjong Katong Girls’ School 7 Sec 4 Preliminary Examination 2025 4 Fig. 4.1 shows part of the human alimentary canal. Fig. 4.1 (a) On Fig. 4.1, name and label the structure (i) that is involved in digestion of proteins in acidic conditions, [1] (ii) where most absorption of water takes place, and [1] (iii) where undigested food materials are stored temporarily. [1] (b) (i) On Fig. 4.1, draw and label the organ that produces bile. [1] (ii) Describe the role of bile in digestion. ………………………………………………………………………………………. ………………………………………………………………………………………. ………………………………………………………………………………………. ...………………………………………………………………………………… [2]

Tanjong Katong Girls’ School 8 Sec 4 Preliminary Examination 2025 (c) Fig. 4.2 shows a region in the human alimentary canal. Fig. 4.2 (i) Name structure W. …………………………………………………………………………………... [1] (ii) Explain what may happen if the number of structure X is reduced. ………………………………………………………………………………………. ………………………………………………………………………………………. …………………………………………………………………………………... [2] [Total: 9] X W

Tanjong Katong Girls’ School 9 Sec 4 Preliminary Examination 2025 5 Fig. 5.1 shows two varieties of moths of the same species. One variety has pale, speckled wings. A second variety has black wings. There are no intermediate forms. Fig. 5.1 Equal numbers of both varieties are released into the woods made up of trees with pale bark. (a) After two years, a survey of the moths is conducted in the area . The results are shown in Table 5.1. Table 5.1 wing colour of moth number of moths two years ago number of mo