2024 VJC H2 Bio P1 QP

1 VICTORIA JUNIOR COLLEGE JC 2 PRELIMINARY EXAMINATION 2024 HIGHER 2 NAME : ……………………………………………………….………………. CT CLASS: ………………..……… BIOLOGY Paper 1 Multiple Choice 9744 / 01 20/09/2024 1 hour Additional Materials: Multiple Choice Answer Sheet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name and class on the Answer Sheet in the spaces 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. 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 use of an approved scientific calculator is expected, where appropriate. This document consists of 20 printed pages. [Turn over]

2 1 The diagram below shows an electron micrograph of a eukaryotic cell. Which of the following options shows the correct functions of the labelled structures? X Y Z A site of photophosphorylation involved in autolysis site of protein synthesis B site of oxidative phosphorylation involve in secretion of proteins site of glycolysis C site of photophosphorylation involve in rRNA synthesis site of glycolysis D site of oxidative phosphorylation involved in autophagy site of protein synthesis

3 2 The table shows the diameter of some atoms when they form bond s. atom single bond / nm double bond / nm H 0.060 - O 0.132 0.110 N 0.140 0.120 C 0.154 0.134 Using the table, the approximate length of an amino acid is estimated to be 0.7 nm. What would be the approximate length of a dipeptide formed using this amino acid? A 0.9 nm B 1.2 nm C 1.4 nm D 1.7 nm 3 Which row shows the chemical g roups present in the biological molecules listed? biological molecule presence of carboxyl (COOH) groups presence of two or more hydroxyl (OH) groups 1 amino acid yes no 2 β glucose no yes 3 glycerol no no 4 fatty acid yes no A 1, 2 and 3 B 1, 2 and 4 C 1, 3 and 4 D 2, 3 and 4

4 4 The graph shows the activity of an enzyme at four different te mperatures, with all other conditions being constant. What conclusion can be drawn from the graph? A No enzyme denaturation occurs at temperatures below 40 oC. B The optimum temperature for the enzyme is 30 oC in all incubation times. C The V max of enzyme activity is reached after 36 hours at 50 oC. D There are more functional enzyme molecules after 48 hours at 2 0 oC than 40 oC. 5 The action of the enzyme hexokinase, which catalyses the phosp horylation of glucose, is shown below. Which statements describe the behaviour of this enzyme? 1 The action of the enzyme illustrates the ‘lock and key’ hypot hesis. 2 The active site for ATP is formed only in the presence of glu cose. 3 The enzyme catalyses both hydrolysis and condensation reactio ns. 4 The activation energy is lowered as substrates are placed in the correct orientation. A 1 and 4 only B 1, 2 and 3 C 2, 3 and 4 D 2 and 4 only

5 6 When investigating enzyme-substrate interactions, which one of the following would be expected to show a linear relationship under constant conditions? A amount of product against time, with the amount of substrate limited B rate of reaction against substrate concentration, with the amo unt of enzyme limited C rate of reaction against enzyme concentration, in the presence of excess substrate D rate of reaction against enzyme concentration, with the amount of substrate limited 7 For most stem cells, once they are differentiated, they lose t he ability to turn into other types of cell. However, some fully differentiated cells can be stimul ated to change back into stem cells in tissue culture. Such cells are called induced pluripotent stem cells (iPS cells). In experiments with mice, it was discovered that the introducti on of four genes would cause certain fully differentiated cells to change to iPS cells. Genes were introduced into host mouse cells using artificially synthesised plasmids. There is evidence to suggest that the introduction of the four genes caused an increase in the production of telomerase reverse transcriptase (TERT) in the fully differentiated cells. Which statements are correct? 1 The iPS cells are useful for research because they have the a bility to differentiate into cells of the extra-embryonic membranes. 2 Only a few genes were required to be added because these gene s were likely able to influence the activity of many other genes by coding for transcription factors. 3 TERT, which plays a part in maintaining the length of the tel omere at the end of a chromosome, is not normally switched on in differentiated cells. 4 This method of creating iPS cells has less ethical concerns t han harvesting embryonic stem cells. A 1, 2 and 3 B 1, 2 and 4 C 1, 3 and 4 D 2, 3 and 4 8 Which statements correctly describe the role of rRNA in protei n synthesis? 1 It helps to align mRNA and tRNA molecules during translation. 2 It links specific amino acids to different tRNA molecules. 3 It catalyses the addition of amino acids to the C-terminus of the polypeptide. 4 Together with ribosomal proteins, it binds mRNA to the riboso me. A 1 and 2 only B 1, 3 and 4 C 2, 3 and 4 D 3 and 4 only

6 9 During the process of protein synthesis, individual amino acid s are combined with individual nucleic acid molecules in the cytoplasm of a cell. Which four nitrogenous bases, represented by their initial letters, make up the variable regions of these nucleic acid molecules? A A C G T B A C G U C A C T U D C G T U 10 In an experiment modelled after that of Meselson and Stahl, bacteria having DNA fully labelled with the light isotope of nitrogen ( 14N) were transferred to a medium containing only the heavy isotope of nitrogen (15N). The bacteria were allowed to reproduce for two generations in this medium. Which statement would be true of the DNA of the second generation? A All DNA molecules will have 15N nucleotides. B 50% of DNA molecules will have 14N nucleotides only and 50% will have half 15N and half 14N nucleotides. C 50% of DNA molecules will have 14N nucleotides only and 50% will have 15N nucleotides only. D 25% of DNA molecules will have 14N nucleotides and 75% will have 15N nucleotides.

7 11 The diagram below shows the distribution of cells of varying D NA content during interphase. Which of the following statements can be concluded from the diagram above? 1 Most of the cells are in G1 phase. 2 All cells in area Z will eventually complete the nuclear division. 3 Area Y represents the number of cells undergoing anaphase. A 1 only B 1 and 3 only C 2 and 3 only D 1, 2 and 3

8 12 When there is low availability of nutrients, yeast cells can e xit the mitotic cell cycle and enter the meiotic cell cycle. Researchers grew a culture of yeast cells in nutrient-rich medi um and then transferred them to nutrient-poor medium to induce meiosis. The data below shows the changes in DNA content after the induction. time after induction (hours) average amount of DNA per cell (µg) 0.0 24.0 1.0 24.0 2.0 40.0 3.0 47.0 4.0 47.5 5.0 48.0 6.0 48.0 7.0 47.5 8.0 25.0 9.0 24.0 10.0 23.5 11.0 14.0 12.0 13.0 13.0 12.5 14.0 12.0 Which of the following statements is true? A Meiosis is only induced 9 hours after transferring to the nutr ient-poor medium. B After 9 hours, the chromosome number in each yeast cell is hal ved. C 5 hours after the induction, there is a doubling of the chromo some numbe