2024 RI H2 Bio P1 QP

© RI 2024 Preliminary Examination 9744/01 [Turn over RAFFLES INSTITUTION 2024 Year 6 Preliminary Exam Higher 2 BIOLOGY 9744/01 Paper 1 Multiple Choice 24 Sept 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 shade your Index Number on the Answer Sheet in the spaces provided unless this has been done for you. There are thirty 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 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 booklet. The use of an approved scientific calculator is expected, where appropriate. (Erase all mistakes completely. Do not bend or fold the OMR Answer Sheet). This document consists of 20 printed pages. Raffles Institution Internal Examination

2 © RI 2024 Preliminary Examination 9744/01 1. The figure below shows part of the structure of a proteinaceous enzyme. Which of the following correctly describe the structure in box Z? number of amino acids present number of types of bond (s) present between amino acids A cannot be determined only 2 B approximately 11 amino acids only 2 C approximately 10 amino acids only 3 D approximately 7 amino acids only 1

3 © RI 2024 Preliminary Examination 9744/01 [Turn over 2. The end-product of a metabolic pat hway can act as a competitive inhibitor. This is called end-product inhibition and allows a cell to control a metabolic pathway. The diagram shows a metabolic pathway where the end-product could act as an inhibitor of enzyme W. Which of the following statements would be true if enzyme Z was inhibited by the end-product instead of enzyme W? 1 The quantity of intermediate 1 would increase 2 The quantity of interm ediate 1 would decrease 3 The quantity of end-product would remain unchanged 4 The quantity of intermediate 3 would decrease 5 There would be wastage of resources A 1 and 5 only B 2, 3 and 4 only C 1, 3 and 5 only D 2, 3, 4 and 5 only

4 © RI 2024 Preliminary Examination 9744/01 3. Four students were asked to match the function of some cell structures in an animal cell with their appearance. The functions were listed by number. 1 produces the mitotic spindle during cell division 2 synthesis of polypeptides 3 synthesis of lipids The appearances were listed by letter. V membranes which surro und an enclosed inner cavity W non-membrane-bound, spherical structures X a double membrane interspersed with pores Y non-membrane-bound, cylindrical structures Z membrane-bound sacs, arranged as a flattened sac Which student correctly matched the functions with the appearance of the cell structure? student 1 2 3 A W X Z B W Z V C Y W V D Y Z W 4. Batrachotoxin is a poison found in frogs in the Columbian jungl e. The poison is used to produce poison darts. The poison works by increasing the permeability of the cell surface membrane of nerve and muscle cells to sodium ions, which move out of the cells. Four statements are made about how the poison affects the cells. 1 Water leaves the cells by osmos is, causing the cells to shrink. 2 Water enters the cells by osmosis, causing the cells to burst . 3 When the sodium ions move out of the cells the intracellular fluid has a more positive water potential than the extracellular fluid. 4 When the sodium ions move out of the cells the extracellular fluid has a more positive water potential than the intracellular fluid. Which statements are correct for the cells affected by batrachotoxin? A 1 and 3 B 1 and 4 C 2 and 3 D 2 and 4

5 © RI 2024 Preliminary Examination 9744/01 [Turn over 5. The mitotic index is a measure of the proportion of cells that are undergoing mitosis in an area 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 located 0.2 mm from the tip of the ro ot, 6 would be undergoing mitosis.

6 © RI 2024 Preliminary Examination 9744/01 6. The following experiment was carried out. 1 Haploid cells, containing three chromosomes each, were grown in a medium containing radioactive thymine, so that all the DNA was labelled. 2 Cells in early interphase were then transferred to a medium where the available thymine was not radioactive and allowed to divide once. 3 A single cell was immediately isolated and allowed to divide once more. 4 When the two d aughter cells reached the next metaphase, they were fixed and their three chromosomes were inspected for radioactivity. Which diagram represents a possible distribution of radioactivity at metaphase in the two daughter cells? normal chromatid radioactive chromatid daughter cell 1 daughter cell 2 key

7 © RI 2024 Preliminary Examination 9744/01 [Turn over 7. Part of the genetic code specifying amino acids is shown in the table below. codon in mRNA amino acid codon in mRNA amino acid AAA AUG AGG / CGC/ CGG GGG UGG lysine methionine arginine glycine tryptophan CCU/ CCA/ CCC/ CCG UAU proline tyrosine During translation initiation, the small ribosomal subunit atta ches to the 5’ untranslated region (UTR) and slides to the START codon. A section of an mRNA sequence is shown below. 5’ U A U A A A A U G C C U U G G 3’ 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 From the above information, how many of the predictions stated below are correct? I The insertion of an additional nucleotide before position 2 w ould be expected to result in greater change in the amino acid chain than an insertion after position 12. II The substitution of a differ ent nucleotide at position 12 would produce no alteration in the amino acid chain. III The substitution of a different nucleotide at position 13 w ould result in the production of an amino acid chain with one alteration. IV The deletion of a nucleotide at position 5 would result only in an alteration in the second amino acid in the chain. A 4 B 3 C 2 D 1 8. The descriptions below are of nucleic acids in eukaryotes. I a polynucleotide of variable length formed by base pairing II a small polynucleotide with a specific 3-D shape III a small polynucleotide with a specific shape, and is associated with proteins IV a large polynucleotide with super coiled sections, and is as sociated