SAJC Prelims H2 Bio P4 Ans

1 St Andrew’s Junior College 2024 9744/04/Preliminary Examinations Civics Group Index Number Name (use BLOCK LETTERS) ST. ANDREW’S JUNIOR COLLEGE 2024 JC2 PRELIMINARY EXAMINATION H2 BIOLOGY 9744/04 Paper 4: Practical Exam Tuesday 20th August 2024 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 is 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 / 23 2 / 12 3 / 20 Total / 55 This document consists of 21 printed pages. [Turn over Marker’s comments: Please remember to write down your shift and lab no. in the provided box when asked to do so. H2

2 St Andrew’s Junior College 2024 9744/04/Preliminary Examinations Question 1 Agar stained with universal indicator can be used to investigate diffusion. When hydrochloric acid diffuses into the agar it changes the colour from green to pink. You will investigate the diffusion of different concentrations of hydrochloric acid in agar. You are provided with the materials shown in Table 1.1. Table 1.1 labelled contents hazard volume/ cm3 H 2.0 mol dm-3 hydrochloric acid irritant 20.0 W distilled water none 40.0 2 Petri dishes containing agar none - sheet T sheet T - - If H comes into contact with your skin, wash off immediately with cold water. It is recommended that you wear suitable eye protection. You will need to: ● prepare different concentrations of hydrochloric acid, H ● measure the diffusion distance for each concentration of hydrochloric acid. You will need to carry out a serial dilution of the 2.0 mol dm –3 hydrochloric acid, H, to reduce the concentration by half between each successive dilution. You will need to prepare four concentrations of hydrochloric acid in addition to 2.0 mol dm –3 hydrochloric a