2026 NJC H2 Bio Prelim P2 (QP)

©NJC 2026 9477/02/SH2 Preliminary Examination [Turn over NATIONAL JUNIOR COLLEGE, SINGAPORE Senior High 2 Preliminary Examination Higher 2 CANDIDATE NAME BIOLOGY CLASS 2bi2_____ REGISTRATION NUMBER Biology Paper 2 Structured Questions Candidates answer on the Question Paper. No Additional Materials are required. 9477/02 21 August 2026 2 hours READ THESE INSTRUCTIONS FIRST Write your name, Biology class and registration number in the spaces at the top of this page. 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. Answer all questions in the spaces provided on the Question Paper. The use of an approved scientific calculator is expected, where appropriate. You may lose marks if you do not show your workings or if you do not use appropriate units. The number of marks is given in the brackets [ ] at the end of each question or part of question. For Examiner’s Use Section A 1 9 2 9 3 11 4 11 5 8 6 11 7 13 8 10 9 8 Total 90 This document consists of 31 printed pages and 1 blank pages.

2 ©NJC 2026 9477/02/SH2 Preliminary Examination Answer all the questions. 1 Fig. 1.1 shows some organelles and storage molecules in a mouse liver cell. Fig. 1.1 (a) Name the storage polysaccharide A. A [1] (b) (i) Name organelle B. B [1] (ii) B and C are the same organelle. Suggest why B and C appear to have different shapes. [1] (c) D is a ribosome. Identify two features visible in Fig. 1.1 that distinguishes D from A. [2]

3 ©NJC 2026 9477/02/SH2 Preliminary Examination [Turn over (d) Scientists investigated the effect of ethanol on the changes in cell organelles in mice by using electron micrographs to estimate the volume of organelles as a percentage of the total cell volume. Table 1.1 shows the volumes of smooth endoplasmic reticulum (sER) and mitochondria as a percentage of the total cell volume in liver cells of control mice (unexposed to ethanol) and mice chronically exposed to ethanol. Table 1.1 organelle volume of organelles as a percentage of the total cell volume control mice mice chronically exposed to ethanol smooth endoplasmic reticulum (sER) 5.5 8.4 mitochondria 21.3 26.5 With reference to Table 1.1, describe and explain the changes in volume of sER and mitochondria in the mice chronically exposed to ethanol compared to the control mice. [4] [Total: 9]

4 ©NJC 2026 9477/02/SH2 Preliminary Examination Question 2 starts on page 5.

5 ©NJC 2026 9477/02/SH2 Preliminary Examination [Turn over 2 Fig. 2.1 is a simplified diagram showing the structure of callose. Not all hydrogen atoms are shown. Fig. 2.1 (a) Complete Table 2.1 to compare the structure of callose with cellulose. Table 2.1 feature callose cellulose monosaccharide used to synthesise the polysaccharide bond connecting monosaccharides orientation of monosaccharides in the molecule [3]

6 ©NJC 2026 9477/02/SH2 Preliminary Examination (b) Plasmodesmata are tiny pores in the cell walls of plants that connect neighboring cells. Fig. 2.2 shows the regulation of plasmodesmata pore size by callose. Fig. 2.2 (i) With reference to Fig. 2.2, describe how the synthesis of callose regulate plasmodesmata pore size. [3]

7 ©NJC 2026 9477/02/SH2 Preliminary Examination [Turn over (ii) Suggest one advantage to the plant in regulating plasmodesmata pore size through callose synthesis and degradation. [1] (iii) Suggest why cellulose, despite also being a structural polysaccharide, would not be suitable for the regulation of plasmodesmata pore size shown in Fig. 2.2. [2] [Total: 9]

8 ©NJC 2026 9477/02/SH2 Preliminary Examination 3 (a) Fig. 3.1 shows the elongation of a segment of DNA strand. Fig. 3.1 (i) Name the nitrogenous base of the incoming nucleotide. [1] (ii) Describe the sequence of events that occurs at the stage shown in Fig. 3.1 to extend the DNA strand. [3]

9 ©NJC 2026 9477/02/SH2 Preliminary Examination [Turn over (iii) The two strands in a molecule of DNA are described as antiparallel. With reference to Fig. 3.1, state what is meant by antiparallel, and explain how the antiparallel arrangement of the strands determines how new strands are synthesised. [3] (b) Complementary base-pairing is one mechanism for maintaining accuracy of genetic information across successive cell generations. (i) Explain another mechanism that helps to maintain accuracy of the genome across successive cell generations. [2] (ii) Describe two possible consequences when accuracy of genome is not maintained across successive cell generations. [2] [Total: 11]

10 ©NJC 2026 9477/02/SH2 Preliminary Examination 4 (a) A new insect species was recently discovered. Female insects of this species are homogametic, and the species follows the XY sex determination system. It was observed that there are three different eye colours in the species. These eye colours are determined by two genes, Gene B and Gene R, which are found on different chromosomes. One of the genes is present on the X chromosome while the other is found on an autosome. Fig 4.1 shows the formation of eye pigment in this species. Fig 4.1 The dominant B allele converts a blue pigment into a purple pigment while the dominant R allele converts the purple pigment into a red pigment. (i) State the name of this type of interaction between the two genes. [1] (ii) A true-breeding blue-eyed male was crossed to a true-breeding purple-eye female. All F1 offspring from this cross had red eyes. Identify the gene that is located on the X chromosome. [1] Blue pigment Purple pigment Red pigment Enzyme B Enzyme R