EJC 2023 H2 9744 P3 (QP)

©EJC 2023 9744/03/J2H2PRELIM/2023 [Turn over EUNOIA JUNIOR COLLEGE JC2 Preliminary Examinations 2023 General Certificate of Education Advanced Level Higher 2 CANDIDATE NAME CIVICS GROUP 2 2 - REGISTRATION NUMBER H2 Biology Paper 3 Long Structured and Free-response Questions 9744/03 19 September 2023 2 hours Additional Materials: 12-page Answer Booklet READ THESE INSTRUCTIONS FIRST Write your name, civics group and registration number on all the work you hand in. Write your answers in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use paper clips, highlighters, glue, or correction fluid/tape. Section A Answer all questions on the Question Paper. Section B Answer one question on the 12-page Answer Booklet provided. Write your answer to each part of the question on a fresh sheet of 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. At the end of the examination, ensure that you submit both the Question Paper and Answer Booklet. This document consists of 12 printed pages. For Examiner’s Use Section A 1 2 3 Section B 4 OR 5 Total 75

2 ©EJC 2023 9744/03/J2H2PRELIM/2023 Section A Answer all questions on the Question Paper. 1 Scientists have produced structures known as virosomes, which are used in certain vaccines. Virosomes do not cause disease. Fig. 1.1 is a diagram of a section through a virosome used in some vaccines to protect against the influenza virus. Fig. 1.1 (a) (i) State the structural differences between a virosome and a virus. ……………………………………………………………………………………………………… …………………………………………………………………………………………………….... ……………………………………………………………………………………………………… ………………………………………………………………………………………………...….[2] (ii) Explain how the structure of the virosome shown in Fig. 1.1 suggests that the central area of the virosome is aqueous. ……………………………………………………………………………………………………… …………………………………………………………………………………………………….... ……………………………………………………………………………………………………… ………………………………………………………………………………………………...….[2]

3 ©EJC 2023 9744/03/J2H2PRELIM/2023 [Turn over (b) The glycoproteins haemagglutinin and neuraminidase found in the influenza virus are also found in the virosomes used in a vaccine against the influenza virus. Briefly explain why haemagglutinin is present in virosomes used in the vaccine for influenza. ..................................................................................................................................................... ..................................................................................................................................................... ..................................................................................................................................................... ..................................................................................................................................................... ..................................................................................................................................................... .................................................................................................................................................[3] Fig. 1.2 shows the antibody concentration in a patient’s serum after he was vaccinated with the virosome. Fig. 1.2 (c) (i) On Fig. 1.2, illustrate the antibody concentration in the patient’s serum over time, after he was exposed to an influenza virus with the same haemagglutinin and neuraminidase found on the virosome that he was vaccinated with. [1] virosome administered time / days antibody concentration in serum / arbitrary units exposure to influenza virus

4 ©EJC 2023 9744/03/J2H2PRELIM/2023 (ii) Explain your answer to (c)(i). ……………………………………………………………………………………………………… …………………………………………………………………………………………………….... ……………………………………………………………………………………………………… …………………………………………………………………………………………………….... ……………………………………………………………………………………………………… ………………………………………………………………………………………………...….[3] (d) (i) The white blood cells that produce antibodies originate from a stem cell. Identify the stem cells in the body that these white blood cells are derived from. ………………………………………………………………………………………………...….[1] (ii) Describe the differentiation potential of these stem cells. ……………………………………………………………………………………………………… …………………………………………………………………………………………………….... ……………………………………………………………………………………………………… ………………………………………………………………………………………………...….[2] (e) Due to the emergence of new strains of influenza virus, a new influenza vaccine has to be developed periodically. Other than mutations, explain how new strains of influenza virus can come about. ..................................................................................................................................................... ..................................................................................................................................................... ..................................................................................................................................................... ..................................................................................................................................................... ..................................................................................................................................................... ..................................................................................................................................................... ..................................................................................................................................................... .................................................................................................................................................[4]

5 ©EJC 2023 9744/03/J2H2PRELIM/2023 [Turn over Fig. 1.3 shows a stage of protein synthesis during the reproductive cycle of influenza virus. This takes place in the cytosol of a human cell. Fig. 1.3 (f) (i) Name the stage of protein synthesis shown in Fig. 1.3. ………………………………………………………………………………………………...….[1] (ii) State the base sequence of the anticodon on structure D. ………………………………………………………………………………………………...….[1] (iii) Explain the roles of structure A in the reproductive cycle of influenza virus. ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ………………………………………………………………………………………………...….[3]

6 ©EJC 2023 9744/03/J2H2PRELIM/2023 (iv) After the synthesis of structure C is completed, it will fold into a viral protein. Suggest if this viral protein is likely to be haemagglutinin or RNA -dependent RNA polymerase. Explain your answer. ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ………………………………………………………………………………………………...….[2] (g) In a human cell, proteins can undergo post-translational modifications. Explain the significance of such modifications. ..................................................................................................................................................... ...................................