SGSS Pure Biology Prelim 2024 Paper 2

St. Gabriel’s Secondary School 2024 ‘O’ Preliminary Examination Subject : Biology Paper : 6093 / 2 Level/Stream : Sec 4 Express Duration : 1 hour 45 min Date : 20 August 2024 Setter : Ms Jane Zhou ▪ Section B: Answer one question. ▪ You are advised to spend no longer than 50 minutes on Section A. INFORMATION FOR CANDIDATES The number of marks of each part-question is shown in brackets. This question paper consists of 20 printed pages including this cover page. Name: …………………………………………… ( ) Class: Sec ……………… READ THESE INSTRUCTIONS FIRST Write your name, index number and name 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. Section B Answer one question. Write your answers in the spaces provided. 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. For Examiner’s Use Sect. A / 70 Sect. B / 10 TOTAL / 80

2 SGSS/BIOP2/4EPrelim/2024 Section A Answer all questions. 1 Food poisoning can be caused by bacteria -infested foods that have been left out in the open for a long time. One such bacteria is Campylobacter. People with Campylobacter infections in the intestines are often prescribed a medicine called erythromycin. Erythromycin is an antibiotic that is known to reduce Campylobacter bacteria counts. Fig. 1.1 below shows the concentration of Campylobacter protein after erythromycin intake. Fig. 1.1 (a) Patients are advised to be administered erythromycin every 6 hours. Suggest the concentration of Campylobacter protein at the sixth hour by extending the line, before the next dose of erythromycin is administered. ………………………………………….………………………………............................ [1] (b) Describe and explain the results in Fig. 1.1, from 2 h to 4 h after erythromycin intake. ………………………………………………………...……………………............................ ………………………………………………………...……………………............................ ………………………………………………………...……………………............................ ………………………………………………………...……………………............................ ………………………………………………………...……………………............................ ………………………………………………………...……………………............................ ………………………………………………………...……………………............................ ………………………………………………………...……………………............................ ………………………………………….………………………………............................ [4] 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 Concentration of Campylobacter protein / 100 cells per ml Duration after erythromycin intake / h

3 SGSS/BIOP2/4EPrelim/2024 (c) Some Campylobacter sa