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 trans