Dunman 2025 6093 P2 prelims QP

This document consists of 22 printed pages DUNMAN SECONDARY SCHOOL CANDIDATE NAME CLASS INDEX NUMBER PRELIMINARY EXAMINATION 2025 SECONDARY 4 EXPRESS BIOLOGY 6093/02 Paper 2 28 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 all the work you hand in. Write in dark blue or black pen. You may use an 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 on the Question Paper. Section B Answer all the questions, the last question is in the form either/or. Write your answers in the spaces provided on the Question Paper. 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.

2 6093/02/Prelims/4Exp/2025 Section A Answer all questions. 1 (a) The p hloem is used to transport sucrose and amino acids in plants. Aphids are used to investigate how plants transport sucrose. Fig. 1.1 shows an aphid with its mouthparts inserted into a leaf to feed on the liquid in the phloem. A potato plant was put in a dark cupboard for several days. Four aphids, A, B, C and D, were then placed on the plant in the dark cupboard as shown in Fig. 1.2. Immediately after the aphids were placed on the plant it was observed that: • all the aphids ingested the same volume of liquid from the phloem. • aphid D ingested the highest concentration of sucrose. Explain why aphid D ingested the highest concentration of sucrose. …………………………………………………………………………………………….…………….. …………………………………………………………………………………………….…………….. …………………………………………………………………………………………….…………….. …………………………………………………………………………………………….…………….. …………………………………………………………………………………………….…………….. …………….………………………………………………………………………….……….…...... [3]

3 6093/02/Prelims/4Exp/2025 (b) Fig. 1.3 shows some cells on the surface of a leaf from a plant. Fig. 1.3 State two differences, visible in Fig. 1.3 between guard cells and epidermal cells. 1 …………………….………………………………….………….……………………….…………... ………………………………………………………………………………………….……………….. 2 …………………….………………………………….………….……………………….…………... ………………………………………………………………………………………….……………….. [2] (c) The potato plant has purple flowers that are usually insect -pollinated. After pollination the seeds formed can grow into new plants. Explain why these plants may show features different from the parent plants. ………………………………………………………………………………………….……………….. ………………………………………………………………………………………….……………….. ………………………………………………………………………………………….……………….. …………….………………………………………………………………………….……….…...... [2] [Total: 7]

4 6093/02/Prelims/4Exp/2025 2 Fig. 2.1 and Fig. 2.2 are diagrams of transverse sections of the human heart during different stages of the cardiac cycle. The sections pass through the heart at a level that is just above the valves. Fig. 2.1 Fig. 2.2 (a) (i) Name valve E on Fig. 2.1 and valve F on Fig. 2.2. E …………………………………………………………….………….……….…….….......... F …………………………………………………………….………….……….…….….... [2] (ii) With reference to the chambers of the heart and the main blood vessels, describe the flow of blood through the heart that occurs when the transverse section of the heart appears as shown in Fig. 2.1. ……………….………………………………………………..………………………………… ……………….………………………………………………..………………………………… ……………….………………………………………………..………………………………… ………………………………………………………………..………….……….……….... [2] (b) Identify the stage of the cardiac cycle shown in Fig. 2.2. Give a reason for your answer. stage of cardiac cycle …………………………………………………………………………………. reason ………….………………………………………………………….…………….…….………. …………………………………………………………………………………………….…………….. …………….………………………………………………………………………….……….…...... [2]

5 6093/02/Prelims/4Exp/2025 (c) Fig. 2.3 shows the heart of a man with coronary heart disease (CHD). Fig. 2.3 The heart needs to respond to extra demands during strenuous exercise. Explain why, during strenuous exercise, the heart of a person with CHD would not respond as efficiently as the heart of a healthy person. …………………………………………………………………………………………….…………….. …………………………………………………………………………………………….…………….. …………………………………………………………………………………………….…………….. …………………………………………………………………………………………….…………….. …………………………………………………………………………………………….…………….. …………….………………………………………………………………………….……….….... [3] [Total: 9]

6 6093/02/Prelims/4Exp/2025 3 Soya beans and beef are both good sources of protein. Table 3.1 shows the nutritional content of products made from soya and beef. Table 3.1 nutritional content per 100 g of product product energy kJ protein / g saturated fat / g fibre / g corned beef 905 26.9 12.1 0.0 soya sausages 1128 19.0 2.1 2.0 (a) Explain two reasons why soya sausages may be healthier than corned beef in a regular diet. 1 …………………….………………………………….………….……………………….…………... ………………………………………………………………………………………….……………….. ………………………………………………………………………………………….……………….. ………………………………………………………………………………………….……………….. 2 …………………….………………………………….………….……………………….…………... ………………………………………………………………………………………….……………….. ………………………………………………………………………………………….……………….. …………….………………………………………………………………………….……….….... [4] (b) An average adult man needs 0.8 g of protein per kilogram of body weight daily. Calculate the mass of soya beans an 80 kg man needs to eat to meet the protein requirement. Show your working. [2]

7 6093/02/Prelims/4Exp/2025 (c) Corned beef is produced from cattle that have been fed on soya beans. Explain why it is more energy efficient for humans to eat soya products as a source of protein than corned beef. …………………………………………………………………………………………….…………….. …………………………………………………………………………………………….…………….. …………………………………………………………………………………………….…………….. …………………………………………………………………………………………….…………….. …………………………………………………………………………………………….…………….. …………….………………………………………………………………………….……….….... [3] [Total: 9]

8 6093/02/Prelims/4Exp/2025 4 PTC is a bitter tasting chemical that some humans can taste while others cannot. This is controlled by a single gene with a pair of alleles. Fig. 4.1 shows the inheritance of the ability to taste PTC in a family. Fig. 4.1 (a) (i) The allele for tasting PTC is dominant to the allele for not tasting PTC. State evidence shown in Fig. 4.1 that supports this fact. …………….…………………………………………………………………………………….. …………….…………………………………………………………………………………….. …………….…………………………………………………………………………………….. …………….………………..………………………………………………………….….... [2] (ii) Use the symbols T for the dominant allele and t for the recessive allele to state the genotypes for individuals 2 and 5. individual 2 ………………… individual 5 ………………… [1] (iii) What are the two possible genotypes for individual 3? …………….………………..………………………………………………………….….... [1]

9 6093/02/Prelims/4Exp/2025 (b) A scientist was pouring powdered PTC into a bottle. A small amount of the powder accidentally blew into the air. A short time later another scientist working in the same room said that she had a bitter taste in her mouth from the powder in the air. Describe, with reference to named components of the nervous system, the nervous pathway that led to the scientist detecting that the powder tasted bitter. …………………………………………………………………………………………….…………….. …………………………………………………………………………………………….…………….. …………………………………………………………………………………………….…………….. …………………………………………………………………………………………….…………….. …………………………………………………………………………………………….…………….. …………………………………………………………………………………………….…………….. …………………………………………………………………………………………….…………….. …………………………………………………………………………………