2020 EJC Promo JC1 P2 Bio (Q)

©EJC 2020 9744/02/J1H2PROMO/2020 [Turn over EUNOIA JUNIOR COLLEGE JC1 Promotional Examinations 2020 General Certificate of Education Advanced Level Higher 2 CANDIDATE NAME CIVICS GROUP 2 0 - REGISTRATION NUMBER H2 Biology Paper 2 Structured Questions & Free Response Questions 9744/02 02 October 2020 2 hours Candidates are to answer questions in Section A in this question booklet. Candidates are to answer questions in Section B in the answer booklet provided. Additional Materials: 8-page Answer Booklet READ THESE INSTRUCTIONS FIRST Write your name, civics group and registration number on all the work you hand in. There are two sections in this paper, Section A and Section B. You are advised to plan your time appropriately to complete both Sections. Answer all questions. Write in dark blue or black pen on both sides of the paper. You may use an HB pencil for any diagrams or graphs. Do not use paper clips, highlighters, glue, or correction tape/fluid. 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. This document consists of 15 printed pages and 1 blank page. For Examiner’s Use 1 2 3 4 5 6 7 8 Total 80

2 ©EJC 2020 9744/02/J1H2PROMO/2020 For Examiner’s Use BLANK PAGE

3 ©EJC 2020 9744/02/J1H2PROMO/2020 [Turn over] For Examiner’s Use Section A Answer all the questions in this section. 1 Emperor penguins are the only species of penguin that breed during the Antarctic winter and they may stand still for multiple days to incubate their eggs. In order t o survive in freezing temperatures, the feet of emperor penguins contain a high percentage of unsaturated fats. (a) Explain the significance of unsaturated fatty acids in cell membranes. ……………………………………………………………………………………………….……………… ……………………………………………………………………………………………….….................. ……………………………………………………………………………………………….….................. ……………………………………………………………………………………………….…............. [2] (b) Fig. 1.1 shows the structure of a lipoprotein in the blood of emperor penguins. Lipoproteins transport fats from the liver to other tissues via the bloodstream. The membrane proteins of lipoproteins allow for fats to be deposited to the target tissue. Fig. 1.1 With reference to Fig 1.1, describe how the structure of lipoproteins allow s for fats to be transported from the liver to a specific tissue via the bloodstream. ……………………………………………………………………………………………….……………… ……………………………………………………………………………………………….….................. ……………………………………………………………………………………………….….................. ……………………………………………………………………………………………….….................. ……………………………………………………………………………………………….….................. ……………………………………………………………………………………………….…............. [3]

4 ©EJC 2020 9744/02/J1H2PROMO/2020 For Examiner’s Use (c) Explain how the structure of haemoglobin allows it to transport oxygen efficiently in red blood cells. ……………………………………………………………………………………………….……………… ……………………………………………………………………………………………….….................. ……………………………………………………………………………………………….……………… ……………………………………………………………………………………………….….................. ……………………………………………………………………………………………….….................. ……………………………………………………………………………………………….…............. [3] [Total: 8 marks]

5 ©EJC 2020 9744/02/J1H2PROMO/2020 [Turn over] For Examiner’s Use 2 Beta-glucosidase is an enzyme that converts cellobiose to glucose during cellulose hydrolysis. Samples of beta- glucosidase were extracted from two species of bacteria, Agrobacterium tumefaciens (enzyme A) and Thermotoga maritima (enzyme T). Fig. 2.1 shows the results of an experiment that investigated the effect of temperature between 0°C and 100°C, on the activities of enzyme A and enzyme T. L represents the lowest temperature at which activity of each enzyme was detected. H represents the highest temperature at which activity of each enzyme was detected. Fig. 2.1 (a) With reference to Fig. 2.1, describe the differences in the relative activities of enzymes A and T. ……………………………………………………………………………………………….……………… ……………………………………………………………………………………………….….................. ……………………………………………………………………………………………….……………… ……………………………………………………………………………………………….….................. ……………………………………………………………………………………………….….................. ……………………………………………………………………………………………….…............. [3]

6 ©EJC 2020 9744/02/J1H2PROMO/2020 For Examiner’s Use (b) Explain why an increase in temperature affects the activity of beta-glucosidase. ……………………………………………………………………………………………….……………… ……………………………………………………………………………………………….….................. ……………………………………………………………………………………………….……………… ……………………………………………………………………………………………….….................. ……………………………………………………………………………………………….….................. ……………………………………………………………………………………………….…............. [3] (c) Suggest why enzyme T has a higher optimal temperature as compared to enzyme A. ……………………………………………………………………………………………….……………… ……………………………………………………………………………………………….….................. ……………………………………………………………………………………………….….................. ……………………………………………………………………………………………….…............. [2] [Total: 8 marks]

7 ©EJC 2020 9744/02/J1H2PROMO/2020 [Turn over] For Examiner’s Use 3 Fig. 3.1 shows the gene expression of a ribosomal protein, rS2. Fig. 3.1 (a) (i) List three differences between process X and process Y. ……………………………………………………………………………………………….……… ……………………………………………………………………………………………….……… ……………………………………………………………………………………………….……… ……………………………………………………………………………………………….……… ……………………………………………………………………………………………….……… ……………………………………………………………………………………………….……[3] (ii) Describe how ribosomal subunits are assembled after the rS2 polypeptide is synthesised. ……………………………………………………………………………………………….……… ……………………………………………………………………………………………….……… ……………………………………………………………………………………………….……… ……………………………………………………………………………………………….……… ……………………………………………………………………………………………….……… ……………………………………………………………………………………………….……[3] process X segments to be degraded rS2 DNA ‘cap’ added poly(A) added promoter process Y rS2 polypeptide

8 ©EJC 2020 9744/02/J1H2PROMO/2020 For Examiner’s Use (b) Fig. 3.2 shows a section of the rS2 DNA template strand. Fig. 3.2 (i) State the corresponding base sequence of the mRNA strand. ……………………………………………………………………………………………….…....[1] (ii) The nucleotide indicated by the arrow in Fig. 3.2 undergoes a substitution mutation to C. Describe the effect of this mutation on the function of rS2 protein. ……………………………………………………………………………………………….……… ……………………………………………………………………………………………….……… ……………………………………………………………………………………………….……… ……………………………………………………………………………………………….……… ……………………………………………………………………………………………….……… ……………………………………………………………………………………………….……[3] [Total: 10 marks]

9 ©EJC 2020 9744/02/J1H2PROMO/2020 [Turn over] For Examiner’s Use 4 Several members of an endangered white rhinoceros species were found to be infertile. Scientists found that their germline cells, which give rise to gametes, were not able to undergo meiosis properly. (a) Explain how meiosis gives rise to haploid cells. ……………………………………………………………………………………………….……………… ……………………………………………………………………………………………….….................. ……………………………………………………………………………………………….….................. ………………………………………