2024 NJC H2 Bio P3 QP

©NJC 2024 9744/03/Preliminary Examination [Turn over H NATIONAL JUNIOR COLLEGE, SINGAPORE Senior High 2 Preliminary Examination Higher 2 CANDIDATE NAME BIOLOGY CLASS 2bi2_____ R E G I S T R A T I O N NUMBER Biology Paper 3 Long Structured and Free-response Questions Candidates answer on the Question Paper. Additional Materials: Answer Booklet 9744/03 13 September 2024 2 hours READ THESE INSTRUCTIONS FIRST Write your name, Biology class and registration number on all the work you hand in. Write in dark blue or black pen. You may use an HB for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. Section A Answer all questions in the spaces provided on the Question Paper. Section B Answer any one question in the separate 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. For Examiner’s Use Section A 1 /30 2 /10 3 /10 Section B 4 or 5 /25 Total /75

2 ©NJC 2024 9744/03/Preliminar y Examination This document consists of 15 printed pages and 1 blank page.

3 ©NJC 2024 9744/03/Preliminary Examination [Turn over Section A Answer all the questions in this section. 1 Collagen is a key structural protein found in various tissues t hroughout the body. Its measurements can vary significantly depending on the type a nd function of the collagen. Type I collagen is the most abundant form. Fig. 1.1 shows the structure of type 1 collagen fibrils. Fig. 1.1 (a) (i) Describe the molecular structure of collagen and explain how its structure relates to its function. [5]

4 ©NJC 2024 9744/03/Preliminar y Examination ( i i ) Use Fig. 1.1 to calculate the number of rows of collagen molecules found in the diameter of collagen fibril, D. Assume that: ● t h e d i a m e t e r o f a c o l l a g e n m o l e c u l e i s 1 . 5 n m ● t h e l e n g t h o f h y d r o g e n b o n d b e t w e e n t w o r o w s o f c o l l a g e n m o l e cules is 3.0Å (angstroms). Show your working clearly. Give your answer to the nearest whole number. number of rows of collagen molecules in one collagen fibril = [3]

5 ©NJC 2024 9744/03/Preliminary Examination [Turn over (b) Osteogenesis imperfecta (OI) is a heritable disorder of connective tissues caused by abnormal synthesis or dysfunctional type I collagen. Each type 1 collagen molecule contains two COL1A1 polypeptides and one COL1A2 polypeptide. A study was carried out to examine the mutations in COL1A1 and COL1A2 genes in patients with OI. PCR was carried out to amplify the genes in segments, and the resulting PCR product was used for DNA sequencing to identify the nucleotide sequence. Fig. 1.2 shows a