2023 RI H2 Bio Prelim P4 Questions

©RI 2023 Preliminary Examination 9744/04 [Turn over RAFFLES INSTITUTION 2023 Year 6 Preliminary Examination Higher 2 BIOLOGY 9744/04 Paper 4 Practical 14th August 2023 2 hours 30 minutes Candidates answer on the Question Paper. Additional Materials: As listed in the Confidential Instructions. READ THESE INSTRUCTIONS FIRST Write your index number, CT group and name 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 2B pencil for any diagrams or graphs. Do not use staples, paper clips, highlighters, glue or correction fluid. Answer all questions 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. At the end of the examination, hand in the Question Paper containing your answers. The number of marks is given in brackets [ ] at the end of each question or part of the question. This document consists of 19 printed pages and 1 blank page. CIVICS GROUP CANDIDATE NAME INDEX NUMBER 3 S 0 3 2 For Examiner’s Use 1 2 3 Total Shift Laboratory Raffles Institution Internal Examination

2 ©RI 2023 Preliminary Examination 9744/04 For Examiner’s Use Answer all questions. 1 The kidneys are the organs that remove waste products from the blood and produce urine. Urine can be tested as part of a health check. People who have kidney disease or a urinary tract infection may have unusually high concentrations of protein in their urine. You will be testing a solution that represents a sample of urine from a patient with a possible kidney disease or a urinary tract infection and will be referred to as ‘mock urine’. You will determine the concentration of protein in this sample of mock urine. You are provided with the materials shown in Table 1.1. Table 1.1 labelled contents hazard volume / cm3 P 10.00% protein solution none 20 W distilled water none 50 C 0.15% copper sulfate solution harmful irritant 20 K 5.00% potassium hydroxide solution harmful irritant 20 U mock urine none 10 X unknown none 10 U+X mixture of U and X none 10 You are required to wear suitable eye protection and gloves. If any solution comes into contact with your skin, wash off immediately under cold water.

3 ©RI 2023 Preliminary Examination 9744/04 [Turn over For Examiner’s Use (a) You will need to carry out a serial dilution of the 10.00% protein solution, P, to reduce the concentration by half between each successive dilution. You will need to prepare four concentrations of protein solution in addition to the 10.00% protein solution, P. After the serial dilution is completed, you will need to have 5 cm3 of each concentration available for use. (i) In the space below, draw a table to show how you will prepare the serial dilution. [3]

4 ©RI 2023 Preliminary Examination 9744/04 For Examiner’s Use Carry out step 1 to step 9. 1. Prepare the concentrations of protein solution, as decided in (a)(i), in the plastic vials provided. Use a glass rod to mix the protein solutions. 2. Label five of the test-tubes with the concentrations you prepared in step 1. 3. Put 1cm3 of each concentration of protein solution into the appropriately labelled test - tubes. 4. Label another test-tube 0.00% and put 1cm3 of distilled water, W, into this test-tube. 5. Put 1cm3 of K into each of the labelled test-tubes. Shake gently to mix. 6. Put 1cm3 of C into each of the labelled test-tubes. Shake gently to mix. 7. Leave the test-tubes aside. After 1 minute, shake gently to mix. 8. Observe the colour of the liquid in each test-tube. To see the colour more clearly, it may help to hold a piece of white paper behind the test tube. You may see the same colour in more than one test-tube. 9. Record your results in (a)(ii) using the symbols shown in Table 1.2. Table 1.2 dark purple +++++ ++++ +++ ++ very light purple + blue - (ii) Record your results in an appropriate table. You may use the same symbols for more than one test-tube. [2]

5 ©RI 2023 Preliminary Examination 9744/04 [Turn over For Examiner’s Use You are provided with a sample of mock urine, U. This represents a sample of urine from a patient being tested for possible kidney disease or urinary tract infection. You are also provided with solution X, taken from the human gastrointestinal tract. 10. Label three test-tubes, U, X and U+X respectively. 11. Put 1cm3 of U, X and U+X into each of the test-tubes respectively. 12. Repeat steps 5 to step 8 for the contents of U, X and U+X. (iii) Fig. 1.1 shows a scale of protein concentrations used in this investigation. The position for 0.00% and 10.00% are shown on the scale. Complete the scale in Fig. 1. 1 by showing the positions of the protein concentrations you prepared in step 1. [1] 0.00% 10.00% Fig. 1.1 (iv) Use your results in (a)(ii) and (a)(iii) to estimate the protein concentration of U, X and U+X. Show your estimate s on Fig. 1. 1 by drawing labeled arrows (↓) at the correct positions on the scale. [2]

6 ©RI 2023 Preliminary Examination 9744/04 For Examiner’s Use Table 1.3 shows the total mass of protein present in urine over 24 hours for people with different medical conditions. Table 1.3 medical condition total mass of protein in urine /mg24h–1 no condition <100 urinary tract infection 100–200 kidney tubular disease 200–500 glomerular disease >500 The 10.00% protein solution you used in (a)(i) represents a urine sample collected over a period of 24 hours that contains 1000mg of protein. (v) Using your result in (a)(iv), estimate the concentration of protein in U over a period of 24 hours and state the possible medical condition of the patient indicated by U. Show your working in the space provided. medical condition …………………………………………………………...………………..[2] (vi) Solution X was extracted from the human gastrointestinal tract. Suggest the identity of solution X and explain the basis of your suggestion. ………………………………………………………………………….………………………… …………………………………………………………………………….……………………… ……………………………………………………………………………….…………………… ………………………………………………………………………………….………………… …………………………………………………………………………………….……………… ………………………………………………………………………………………………….[3]

7 ©RI 2023