HCI 2024 Prelim H2 Bio P1 Qn

© Hwa Chong Institution 2024 9744 H2 Biology / JC2 Preliminary Examinations / Paper 1 HWA CHONG INSTITUTION JC2 Preliminary Examinations Higher 2 CANDIDATE NAME CT GROUP 23S7___ CENTRE NUMBER INDEX NUMBER BIOLOGY Paper 1 Multiple Choice Additional Materials: Multiple Choice Answer Sheet 9744/01 17 September 2024 1 hour INSTRUCTIONS TO CANDIDATES 1. Write your name, CT group, Centre number and index number in the spaces provided at the top of this cover page. 2. Fill in your particulars on the Multiple Choice Answer Sheet. Write your NRIC number and shade accordingly. 3. There are thirty questions on this paper. Answer all questions. For each question, there are four possible answers, A, B, C and D. Choose the one you consider correct and record your choice in soft pencil on the separate Answer Sheet. 4. At the end of the paper, you are to submit only the Answer Sheet. INFORMATION FOR CANDIDATES Each correct answer will score one mark. A mark will not be deducted for a wrong answer. Any rough working should be done in this booklet. The used of an approved scientific calculator is expected, where appropriate. This document consists of 22 printed pages.

2 © Hwa Chong Institution 2024 9744 H2 Biology / JC2 Preliminary Examinations / Paper 1 1 The following experiments were conducted by early scientists. Swan Neck Flask Experiment  Louis Pasteur boiled nutrient broth in a flask with a swan neck that allowed air in but prevented dust and microbes from reaching the broth.  The broth remained free of microbial growth until the neck was broken. Observation of Cork Cells  Robert Hooke used a microscope to examine thin slices of cork and observed tiny, box-like structures he called “cells”. Matthias Schleiden and Theodor Schwann's Observations  Schleiden and Schwann proposed that all living organisms are composed of cells, building on Hooke's earlier work. Which of the following statements are consistent with the given information about these experiments? 1 Louis Pasteur demonstrated that cells come from pre-existing cells by showing that microorganisms do not spontaneously generate but come from other microorganisms in the air. 2 Robert Hooke proved that cells are the smallest unit of life, as he observed tiny, box- like structures in cork, which are the fundamental units of its structure. 3 Matthias Schleiden and Theodor Schwann's observations led to the understanding that living organisms are composed of cells, supporting the principle that cells are the basic structural and functional units of life. A 1 only B 2 only C 1 and 2 only D 1, 2 and 3

3 © Hwa Chong Institution 2024 9744 H2 Biology / JC2 Preliminary Examinations / Paper 1 2 A researcher is studying the properties of a toxin produced by a plant. When cellular contents are exposed to the toxin, the cell will die. The table shows the relative percentages of various organelles in cells that are not actively producing the toxin and cells that are actively producing the toxin. cell structure description relative % of cell non-toxin producing cell toxin producing cell V double membrane bound organelle with cristae 12 15 W sheet-like, single membrane bound organelle with continuous lumen 15 20 X single membrane bound organelle arranged in tubules 14 3 Y large, dense, and contains rRNA 3 10 Z single membrane bound organelle that does not contain phospholipids in the lumen. 35 46 Which conclusion is consistent with the data provided? A Toxin production in structure V is energy-intensive, suggesting that the toxin is lipid- soluble. B Protein synthesis is upregulated in structure W, implying that the toxin is protein-based and lipid-soluble. C Increased ribosome production in structure Y suggests the toxin is RNA-based and water-soluble. D Structure Z stores the water-soluble toxin. 3 In an experiment, fluorescent dyes were attached to proteins on the outer surface of cell surface membranes. Fluorescent dyes of one colour were attached to proteins of a living human cell and fluorescent dyes of a different colour were attached to proteins of a living mouse cell. The human cell and the mouse cell were then fused to form a hybrid cell. At first, the proteins attached to different fluorescent dyes remained separate, but after 40 minutes the proteins were distributed randomly across the hybrid cell surface membrane. What does this experiment show? A Proteins are found only on the outer surface of cell surface membranes. B Proteins in the outer layer of a bilayer do not penetrate into the inner layer. C Proteins move freely in the phospholipids of a bilayer. D The cell surface membranes of the two cells are bilayers.

4 © Hwa Chong Institution 2024 9744 H2 Biology / JC2 Preliminary Examinations / Paper 1 4 The diagrams show short sections of some common polysaccharides and modified polysaccharides. The polysaccharides can be described as:  F is composed of β-glucose monomers with 1,4 glycosidic bonds  G is composed of α-glucose monomers with 1,4 glycosidic bonds  H is composed of N-acetylglucosamine monomers with β-1,4 glycosidic bonds. Which row correctly matches the numbered diagrams to the descriptions of the polysaccharides? polysaccharide F polysaccharide G polysaccharide H A 2 1 3 B 2 3 1 C 3 1 2 D 3 2 1

5 © Hwa Chong Institution 2024 9744 H2 Biology / JC2 Preliminary Examinations / Paper 1 5 Measurements of the speed of movement of oxygen (O2) molecules through three types of membranes were made and compared with the speed of movement of O2 molecules through water. The measurements were carried out at four different temperatures. The three types of membranes were: 1 lens lipid, which is the membrane of cells in the eyeball of a calf 2 synthetic membrane composed of palmitic acid with cholesterol (P/CHOL) 3 synthetic membrane composed of palmitic acid without cholesterol (P) The results of the experiment are shown in the graph. Which statement can be deduced based on the results of the experiment? A Water does not impose a barrier to the movement of O 2 molecules that are polar and hydrophilic. B Lens lipid is composed of palmitic acid without cholesterol (P), which ensures high oxygen permeability. C Lens lipid contains high level of cholesterol, which is responsible for low oxygen permeability at low temperatures. D Lens lipid contains high level of cholesterol, which is responsible for high oxygen permeability at high temperatures. P lens lipid P/CHOL water

6 © Hwa Chong Institution 2024 9744 H2 Biology / JC2 Preliminary Examinations / Paper 1 6 CYP3A4 is an important enzyme in the human digestive system where it is needed to break down a range of different toxins and drugs. Furanocoumarins found in some fruits have been shown to interfere with the activity of CYP3A4. The graph represents the effect of furanocoumarins on the breakdown of toxins in the digestive system by CYP3A4 over time. Which of the following statements can be concluded from the information provided? 1 Furanocoumarins reduces the activity of CYP3A4. 2 Furanocoumarins binds reversibly to CYP3A4. 3 Furanocourmarins can result in the accumulation of toxin in the human digestive system. 4 Furanocoumarins decreases the affinity of toxin for CYP3A4’s active site. A 1 and 2 only B 1 and 3 only C 2 and 3 only D 3 and 4 only 7 Which statement correctly describe a feature of stem cells that is essential for their role in cell replacement and tissue repair? A A small population of stem cells is retained in the body of adults throughout their lifetime. B After mitosis of