ACJC Prelim H1 Bio P1 Ans

This paper consists of 20 printed pages. [Turn over Anglo-Chinese Junior College JC2 Biology Preliminary Examination Higher 1 BIOLOGY Paper 1 Multiple Choice Additional Materials: Multiple Choice Answer Sheet 8876/01 15 September 2023 1 hour READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name and index number in the answer sheet provided. 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. Read the instructions on the Answer sheet very carefully. 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 Question Paper. The use of an approved calculator is expected, where appropriate.

2 Anglo-Chinese Junior College 2023 J2 H1 8876 Paper 1 Preliminary Examination 1 How many statements about the nucleus are correct? 1 The nucleolus comprises entirely of heterochromatic DNA. 2 The nuclear pores facilitate the separate movement of rRNA and ribosomal proteins out of the nucleus. 3 The nucleoplasm can only contain pre-mRNA and not mature mRNA. 4 The nuclear envelope will only disintegrate during apoptosis. 5 There will always be only one nucleolus per nucleus. A None AOA B 1 C 2 D More than 2 2 The electron micrograph shows a particular organelle within a eukaryotic cell. Which statements about this organelle are correct? 1 The synthesis of proteins occurs on ribosomes that are attached to the membrane of this organelle. 2 This organelle is made up of multiple flattened sacs known as cisternae. 3 Post-translational chemical modification occurs in the lumen of this organelle. 4 In the liver, this organelle metabolises carbohydrates by breaking down glycogen to glucose. A 1, 2, 3 and 4 B 1, 2 and 3 only C 1 and 4 only D 4 only AOA

3 [Turn over Anglo-Chinese Junior College 2023 J2 H1 8876 Paper 1 Preliminary Examination 3 Gram staining can be used to distinguish between two groups of bacteria with different peptidoglycan cell wall structures. A blue-purple staining dye is first added to the cells, followed by the addition of alcohol to remove the staining dye. Due to the differential retention of the staining dye, the two groups of bacteria are known as Gram-positive and Gram-negative bacteria. Gram-positive bacteria tend to yield blue or purple colouration after staining as the staining dye can be retained within the cell. Gram-negative bacteria will stain pink or red as the staining dye is not retained. The diagram shows the cell wall structures for both Gram-positive and Gram-negative bacteria. Which statement does not explain the differential retention of the staining dye by the Gram-positive and Gram-negative bacteria? A The peptidoglycan layer is thicker in Gram-positive bacteria and hence more stain ing dye is retained as compared to Gram-negative bacteria. B The peptidoglycan layer is thinner in Gram-negative bacteria and hence this group of bacteria tends to stain pink instead of blue or purple. C The thicker layer of peptidoglycan in Gram -positive bacteria will prevent most of the staining dye from entering the cell. D For Gram -negative bacteria, t he outer membrane is disrupted by the addition of alcohol , exposing a thin peptidoglycan layer which allowed the staining dye to leave the cell wall. Low AOB

4 Anglo-Chinese Junior College 2023 J2 H1 8876 Paper 1 Preliminary Examination 4 Chitin is a polysaccharide that is made up of repeating units of N-acetyl-D-glucosamine. The diagram shows three repeating units of N-acetyl-D-glucosamine. Which statement does not correctly compare chitin with other polysaccharides? A Both chitin and cellulose have alternate monomers that are rotated 180° with respect to each other. B Chitin likely exists in the form of straight chains, while amylose chains assume a helical form. C Chitin contains β -1,4-glycosidic bonds whereas amylose contains α -1,4-glycosidic bonds. D Both chitin and amylopectin comprise monomers that contain nitrogen atoms. Low AOB

5 [Turn over Anglo-Chinese Junior College 2023 J2 H1 8876 Paper 1 Preliminary Examination 5 The diagram shows two types of movements that can occur within a phospholipid bilayer. Which statement is correct? A Movement 2 occurs more frequently than movement 1. B Both movements 1 and 2 can also occur for proteins. C When temperature decreases, movements 1 and 2 are reduced. D Movement 1 is reversible but movement 2 is not. AOA 6 The table shows the half-lives of two different thermostable enzymes that are commonly used in Polymerase Chain Reaction . The half -life reflects the time it takes to denature half the amount of the enzymes at 95°C. Each of these polymerases has four cysteine residues within their primary structure. name of DNA polymerase half-life at 95°C / min Taq polymerase 45 PFU polymerase 1140 Which statement can be concluded from the data provided? A Taq polymerase is more thermostable than PFU polymerase as its half-life is about 25 times shorter than that of PFU polymerase. B It takes 1095 more minutes to denature 50% of a fixed amount of PFU polymerase as compared to the same amount of Taq polymerase. C PFU polymerase is more thermostable than Taq polymerase as it has more disulfide bonds within its tertiary structure. D Both enzymes are isolated from organisms that are found in the same thermal spring. Low AOB

6 Anglo-Chinese Junior College 2023 J2 H1 8876 Paper 1 Preliminary Examination 7 Catalase, an enzyme produced by liver tissue, breaks down hydrogen peroxide into water and oxygen. To investigate the effects of changing hydrogen peroxide concentration on the rate of oxygen production, small cubes of fresh liver tissue were added to hy drogen peroxide solutions of different concentrations. The volume of oxygen produced per unit time from each reaction was recorded and the data was shown in a graph. Which statement is correct? A At P, the rate of reaction is limited by the concentration of the substrate. B At R, all the catalase active sites are saturated. C At S, the enzyme concentration is the limiting factor. D At Q, half the total volume of oxygen is collected from the reaction. Low AOB 8 The graph shows the activity of enzymes E, F and G under different pH conditions. Which statement is not a valid conclusion of these enzymes? A The affinity between substrate and enzyme E is highest when the pH is 2.5. B At pH 6.2, the kinetic energy of enzymes F and their substrates is the highest. C Ionic and hydrogen bonds in these enzymes are affected when pH changes. D Rate of reactions catalysed by enzyme F is higher than those catalysed by enzyme E and G at pH 6. Low AOB

7 [Turn over Anglo-Chinese Junior College 2023 J2 H1 8876 Paper 1 Preliminary Examination 9 β cells in the islets of Langerhans of the pancreas release a hormone, insulin, when concentration of blood glucose in the body increases. Type 1 and type 2 diabetes are both characterised by higher-than-normal concentration of blood glucose. In type 1 di