2024 SAJC Prelim H2 Biology P1 (Q)

Civics Group Index Number Name (use BLOCK LETTERS) ST. ANDREW’S JUNIOR COLLEGE 2024 JC2 PRELIMINARY EXAMINATIONS H2 BIOLOGY 9744/01 Paper 1: Multiple Choice Thursday 12th September 2024 1 hour Additional Materials: Multiple Choice Answer Sheet (OTAS) READ THESE INSTRUCTIONS FIRST Do not open this booklet until you are told to do so. Write your name, civics group and index number on the multiple choice answer sheet in the spaces provided. There are 30 questions in 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 multiple choice Optical answer sheet. INFORMATION TO CANDIDATES Each correct answer will score one mark. A mark will not be deducted for wrong answer. Any rough working should be done in this booklet. At the end of the examination, submit both question paper and multiple choice answer sheet. This document consists of 22 printed pages H2

2 SAJC / H2 Biology 9744/1 JC2 Prelim 2024 [Turn over

3 SAJC / H2 Biology 9744/1 JC2 Prelim 2024 1 The electron micrograph shows a structure found in the cytoplasm of an animal cell. Which biological molecule(s) are found in this structure? A Nucleic acids and proteins B Proteins and phospholipids C Nucleic acids only D Proteins only 2 Which diagram(s) shows that a glycosidic bond can be formed? A 1, 2 and 3 B 1 only C 2 and 3 only D 3 only

4 SAJC / H2 Biology 9744/1 JC2 Prelim 2024 3 The diagram shows the structure of a lysozyme molecule. Which statement(s) about lysozyme are correct? 1 The primary structure of lysozyme is made up of 130 amino acids linked by peptid e bonds. 2 Lysozyme has a secondary structure that has repeated patterns stabilised by hydrogen bonds between R groups. 3 Further folding of the polypeptide chain gives an overall specific 3D conform ation due to R groups interactions. 4 Lysozyme is a quaternary globular protein held together by strong disulfide bonds. A 3 only B 1 and 3 C 1 and 4 D 2 and 4

5 SAJC / H2 Biology 9744/1 JC2 Prelim 2024 4 The statements are comparisons of endocytosis and exocytosis.  Both are mechanisms that involve vesicles and the transport of materials across the cell surface membrane.  Both mechanisms occur to allow bulk transport across the cell surface membrane.  Endocytosis involves taking materials into the cell, whereas exocytosis involves the release of materials from the cell.  Some of the cell surface membrane is lost when endocytosis occurs and there is an increase in the cell surface membrane when exocytosis occurs. How many statement(s) is/are correct? A 1 B 2 C 3 D 4 5 Influenza virus has an enzyme called neuraminidase which breaks down glycoproteins in the surface membrane of the cell that the virus will infect. The glycoprotein binds to the active site of neuraminidase by induced fit. Which statements about the induced fit hypothesis of enzyme action are correct? 1 The active site must have the same shape as the substrate for them to bind together. 2 This enzyme is less likely to be affected by non-competitive inhibitors than an enzyme working by the lock-and-key mechanism. 3 The substrate is converted to product by specific R-groups in the active site just like the lock-and-key mechanism. A 1 and 2 B 2 and 3 C 2 only D 3 only

6 SAJC / H2 Biology 9744/1 JC2 Prelim 2024 6 Which of the following components of the human immunodeficiency virus is no t encoded by the viral genome? 7 Which row correctly describes antigenic drift and antigenic shift? Antigenic drift Antigenic shift A achieved by reassortment of gene segments achieved by accumulation of mutations B new viral strain may infect hosts of the same species new viral subtype may infect hosts in a different species C occurs less frequently occurs more frequently D results in major antigenic change results in minor antigenic change

7 SAJC / H2 Biology 9744/1 JC2 Prelim 2024 8 Isotopes of oxygen can be used to distinguish between oxygen absorbed by plants and oxygen evolved. A mixture of oxygen isotopes 16O2 and 18O2 was supplied to a suspension of the unicellular alga Chlorella which had previously been exposed to 16O2 and immersed in H 2 16O only. During the following hour, changes in concentration of these gases in the suspension were mea sured in light and dark conditions. The graph shows the results. What caused the concentration of 16O2 to rise in light? A H2 18O was being photolysed more rapidly than H2 16O B 16O2 was being produced in photosynthesis faster than it was being absorbed in respiration. C 16O2 was being absorbed at different rates in light and dark. D 16O2 was being produced in photosynthesis but was not being absorbed in respiration.

8 SAJC / H2 Biology 9744/1 JC2 Prelim 2024 9 In an experiment, metabolically active cells were introduced to a sealed container o f nutrient solution. The graph of the levels of glucose, carbon dioxide and oxygen were then an alyzed over time. Which of the following can be concluded from the graph? Process happening at interval X Process happening at interval Y A Aerobic respiration Lactic acid fermentation B Aerobic respiration Alcoholic fermentation C Lactic acid fermentation Aerobic respiration D Alcoholic fermentation Aerobic respiration

9 SAJC / H2 Biology 9744/1 JC2 Prelim 2024 10 In a study of a genetic disorder involving one gene, the DNA from six mem bers of a family was isolated, amplified by PCR and run on an agarose gel. The pedigree was construc ted using information obtained from interviewing family members. The results reveal that there are three forms of the gene. Each gene has a different number of repeats in one of its introns. Given the above information, which of the statements are correct? 1 Gene variant B is associated with the disease phenotype. 2 It is possible, but rare, for individuals I1 and I2 to have an affected offspring with gene variant B and C due to crossing over event during meiosis in individual I1. 3 Individual I2 is not the biological father of individual II2. 4 The primers that flank the section of the gene variants are complementary to each other. A 1 and 3 only B 1 and 2 only C 1, 2 and 4 only D 2, 3 and 4 only 11 The mitotic index is a measure of the proportion of cells that are undergoing mitosis in an area

10 SAJC / H2 Biology 9744/1 JC2 Prelim 2024 of tissue. It is calculated using the formula shown. mitotic index = (number of cells undergoing mitosis ÷ total number of cells) × 100 A scientist calculated the mitotic index of areas of onion root at different distances from the tip of the root. The results are shown below. Which statement is correct? A No cell division occurs further than 1.4 mm from the tip of the root. B The rate of cell division decreases as the distance from the root tip decreases. C Most of the cells undergoing cell division are closer to the tip of the root. D For a sample of 200 cells, 0.2 mm from the tip of the root, 6 would be undergoing mitosis. 12 A scientist has two cultures of cells. Culture A consists of normal cell s while culture B consists