2022 EJC Promo JC1 Bio P2 (Q)

©EJC 2022 9744/ J1H2Promotional Examination /2022 [Turn over EUNOIA JUNIOR COLLEGE JC1 Promotional Examination 2022 General Certificate of Education Advanced Level Higher 2 CANDIDATE NAME CIVICS GROUP 2 2 - REGISTRATION NUMBER H2 Biology 9744 / 02 04 October 2022 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 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. Section A Answer all questions in the spaces provided on the Question Paper. Section B Answer all questions in the 12-page Answer Booklet. 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. The number of marks is given in brackets [ ] at the end of each question or part question. At the end of the examination, submit the Question Booklet and the 12-page Answer Booklet separately. This document consists of 19 printed pages and 1 blank page. For Examiner’s Use Section A 1 2 3 4 5 Section B 6 Total 80

2 ©EJC 2022 9744/J1H2Promotional Examination/2022 Section A Answer all questions in the spaces provided. 1 Fig. 1.1 shows the process of collagen synthesis in a fibroblast cell. Fig. 1.1 (a) With reference to Fig. 1.1, describe how procollagen is transported out of the cell. ……………………………………………………………………………………………………………… ……………………………………………………………………………………………………………… ……………………………………………………………………………………………………………… ……………………………………………………………………………………………………………… ……………………………………………………………………………………………………………… …………………………………………………………………………………………………………… [3]

3 ©EJC 2022 9744/ J1H2Promotional Examination /2022 [Turn over (b) The primary structure of a collagen polypeptide has a repeating pattern of three amino acids. Fig. 1.2 shows the two forms of this pattern. Fig. 1.2 Hydroxyproline is a proline molecule that has a hydroxyl ( -OH) group added to its R -group. The hydroxyl groups are involved in hydrogen bonding in tropocollagen. Glycine makes up approximately 30% of the total amino acid composition of collagen. Explain how the structure of glycine plays an essential role in contributing to the high tensile strength of tropocollagen. ……………………………………………………………………………………………………………… ……………………………………………………………………………………………………………… ……………………………………………………………………………………………………………… ……………………………………………………………………………………………………………… ……………………………………………………………………………………………………………… …………………………………………………………………………………………………………… [3]

4 ©EJC 2022 9744/J1H2Promotional Examination/2022 (c) Many of the lysine amino acids in a collagen polypeptide also have a hydroxyl (-OH) group added to their R-group. Fig. 1.3 shows hydroxylysine. Fig. 1.3 (i) On Fig. 1.3, draw a box around the R group of hydroxylysine. [1]

5 ©EJC 2022 9744/ J1H2Promotional Examination /2022 [Turn over The hydroxyl group of hydroxylysine is important as a possible attachment site for a β-galactose molecule. The joining of β -galactose to hydroxylysine involves the formation of a glycosidic bond. The molecular structure of β-galactose is shown in Fig. 1.4. Fig. 1.4 (ii) Show how a glycosidic bond could be formed between carbon 1 of β -galactose and the R group of hydroxylysine. [3] [Total: 10]

6 ©EJC 2022 9744/J1H2Promotional Examination/2022 2 In human retinal photoreceptor cells, the EGFLAM gene codes for a protein known as Pikachurin. The production of this protein is depicted in Fig. 2.1 below. Fig. 2.1 (a) (i) Describe process Y. …….................................................................................................................................... …….................................................................................................................................... …….................................................................................................................................... …….................................................................................................................................... …….................................................................................................................................... .......................................................................................................................................[3] process X process Y

7 ©EJC 2022 9744/ J1H2Promotional Examination /2022 [Turn over (ii) Contrast DNA replication with process X. …….................................................................................................................................... …….................................................................................................................................... …….................................................................................................................................... …….................................................................................................................................... …….................................................................................................................................... …….................................................................................................................................... …….................................................................................................................................... .......................................................................................................................................[4]

8 ©EJC 2022 9744/J1H2Promotional Examination/2022 Fig. 2.2 shows a section of the EGFLAM mRNA molecule. Fig. 2.2 (b) (i) It is known that D and E are complementary bases. Name the parts of the mRNA molecule labelled D, E, F, and G. D: …….............................................. E: …….............................................. F: …….............................................. G: …….............................................. [2] (ii) Explain why the ribosomal proteins that interact with the mRNA molecule are made of mostly positively charged amino acids. …….................................................................................................................................... …….................................................................................................................................... …….................................................................................................................................... .......................................................................................................................................[2]

9 ©EJC 2022 9744/ J1H2Promotional Examination /2022 [Turn over It was discovered that the protein Otx2 plays a large role in regulating the formation of the sensory organs, including the eye and optic nerve. This protein is encoded by the OTX2 gene. Fig. 2.3 shows the changes in mRNA levels of the OTX2 and EGFLAM genes. Fig. 2.3 (c) (i) Calculate the average rate of OTX2 mRNA production over 5 hours. [1] (ii) With reference to Fig. 2.3, describe the changes in EGFLAM mRNA level. …….................................................................................................................................... …….................................................................