RI_H3 _BIO_P1_Qns_2017

2017 Preliminary Examination 9815/01 RAFFLES INSTITUTION Higher 3 PROTEOMICS 9815/01 Paper 1 26 September 2017 2 hour 30 minutes Additional materials: Answer Paper Appendix List of Amino Acids (with Question Paper) READ THESE INSTRUCTIONS FIRST Write your index number, CT group & name on all the work you hand in. Write in dark blue or black pen on both sides of the paper. You may use a soft pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, highlighters, glue or correction fluid. Section A Answer all questions. Section B Answer three out of four questions. Section C Answer the question. At the end of the examination, fasten all your work securely together. Please hand in this question booklet together with your answer sheets. The number of marks is given in brackets [ ] at the end of each question or part question. You may use a calculator. You are reminded for the need for clear presentation in your answers. This document consists of 8 printed pages. CIVICS GROUP CANDIDATE NAME INDEX NUMBER 1 7 S 0 3 Raffles Institution Internal Examination

2 2017 Preliminary Examination 9815/01 [Turn over Section A Answer all the questions in this section. 1 A naïve B cell produces only the membrane-bound form of IgM. When it becomes activated and differentiates into a plasma B cell, it may transiently produce both membrane-bound and secreted forms of IgM, but it will eventually produce only the secreted form. (a) (i) Describe how amino acids in solution are joined. [2] (ii) Discuss the difference between the processes of in vivo (in a cell) and in vitro (in solution outside a cell) joining of amino acids. [2] (b) (i) Using your knowledge of an immunoglobulin structure, compare the amino acid sequences of the membrane-bound and secreted forms of IgM. [3] (ii) Name the process that generated the two forms of IgM. [1] (iii) Describe how the two forms of IgM are targeted to their final destinations. [4] (c) Immune protection is one of the biological proc esses in which proteins play a role. State two other biological processes in which proteins play different crucial roles. For each process, name the protein involved.