SAJC H2 Prelim P4 2023 Student version for sharing

1 St Andrew’s Junior College 2023 9744/04/Preliminary Examinations Civics Group Index Number Name (use BLOCK LETTERS) ST. ANDREW’S JUNIOR COLLEGE 2023 JC2 PRELIMINARY EXAMINATION H2 BIOLOGY 9744/04 Paper 4: Practical Exam Tuesday 22 August 2023 2 hours 30 minutes READ THESE INSTRUCTIONS FIRST Write your name, civics group and index number on all the work you hand in. Give details of the practical shift and laboratory, where appropriate, in the boxes provided. Write in dark blue or black pen. You may use a HB pencil for any diagram, graph or rough working. Do not use staples, paper clips, highlighters, glue or correction fluid. Answer all questions in in the spaces provided on the Question paper. The use of an approved scientific calculator i s expected, where appropriate. You may lose marks if you do not show your working or if you do not use appropriate units. The number of marks is given in brackets [ ] at the end of each question or part question. IMPORTANT INFORMATION TO CANDIDATES: Candidates with access to microscope at the start of the paper are given the first 1h 15 min to use them. Please answer QUESTION 3 within this time frame. Once you have finished working with the microscope, you can move on to QUESTION 1 or 2. Candidates with no access to microscope at the start of the paper should proceed with QUESTION 1 or 2 first. You will be given access to the microscope at 1h 15 min after the start of the paper. Shift Laboratory For Examiner’s Use 1 / 25 2 / 12 3 / 18 Total / 55 This document consists of 21 printed pages. [Turn over H2

2 St Andrew’s Junior College 2023 9744/04/Preliminary Examinations 1 You will investigate the water potential of potato cells. When pieces of potato are put into a sucrose solution, water will move by osmosis into and out of the potato cells. The overall direction of water movement depends on the difference between the water potential of the potato cells and the water potential of the sucrose solution. • If the overall movement of water is out of the potato cells, the sucrose solution will become less concentrated. • If the overall movement of water is into the potato cells, the sucrose solution will become more concentrated. Fig. 1.1 shows how the change in concentration of the sucrose solution after 15 minutes can be assessed. A blue dye is added to the sucrose solution around the potato pieces at the end of the 15 minutes. The blue dye does not affect the concentration of the sucrose solution. After mixing, a drop of the blue sucrose solution is added to the original sucrose solution in a separate test-tube. The movement of the blue drop is then observed. Fig. 1.1 • If the sucrose solution has become less concentrated, then the density of the sucrose solution will have decreased. • If the sucrose solution has become more concentrated, then the densi