2024 EJC Prelim H2 Biology P1 (Q)

©EJC 2024 9744/01/J2H2PRELIM/2024 [Turn over EUNOIA JUNIOR COLLEGE JC2 Preliminary Examination 2024 General Certificate of Education Advanced Level Higher 2 H2 Biology Paper 1 Multiple Choice 9744/01 19 September 2024 1 hour Additional Materials: Multiple Choice Answer Sheet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use paper clips, glue or correction fluid/tape. Write your name, civics group and registration number 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. 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. This document consists of 18 printed pages and 2 blank pages.

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3 ©EJC 2024 9744/01/J2H2PRELIM/2024 [Turn over Answer all questions. 1 Which statement describes how the molecular structure of starch is suited to its function? A Amylose has a branched structure and amylopectin is coiled to give a compact molecule for transport. B In the breakdown of amylose and amylopectin, many condensation reactions release stored energy. C In the formation of amylose and amylopectin, many hydrolysis reactions allow t he release of stored energy. D Amylose and amylopectin form a complex that is insoluble and so does not affect the water potential of the cell. 2 The structure of phospholipids includes: 1 polar phosphate heads 2 hydrophobic fatty acid chains 3 saturated fatty acid chains. What are essential for the formation of a phospholipid bilayer in a cell surface membrane? A 1 and 2 B 1 and 3 C 2 and 3 D 3 only 3 The diagram shows the structure of an amino acid. What is true about this amino acid? 1 It has a hydrophobic R group. 2 It is amphoteric. 3 It is insoluble in water. A 1 only B 3 only C 1 and 2 only D 1, 2 and 3

4 ©EJC 2024 9744/01/J2H2PRELIM/2024 4 What determines the specificity of an enzyme? 1 the covalent and other bonding between R groups of the polypeptide 2 the optimum pH of the enzyme 3 the covalent peptide bonds between amino acids of the polypeptide 4 the shape of the substrate molecule A 1, 2, 3 and 4 B 1 and 3 only C 1 only D 2, 3 and 4 only 5 Which row shows features that occur in plant cells and bacterial cells? key ✓ = found in plant cells and bacterial cells ✗ = not found in at least one of these two types of cell 70S ribosomes 80S ribosomes centrioles circular DNA A ✓ ✗ ✓ ✗ B ✓ ✗ ✗ ✓ C ✗ ✓ ✓ ✗ D ✗ ✓ ✗ ✓ 6 A student used a light microscope to observe a blood smear on a microscope slide. An eyepiece graticule was used to measure the diameter of a white blood cell on the slide. The student recorded that the white blood cell was 5 eyepiece graticule units in diameter. Which additional information does the student need to determine the diameter of the white blood cell in micrometres? A calibration of the eyepiece graticule using a stage micrometer only B calibration of the eyepiece graticule using a stage micrometer and the magnificat ion of the eyepiece lens C the magnification of the eyepiece lens only D the magnification of the eyepiece lens and the magnification of the objective lens

5 ©EJC 2024 9744/01/J2H2PRELIM/2024 [Turn over 7 The plasma membrane is the cell ’s protective barrier as it prevents foreign molecules from entering the cell. However, in drug research experiments, foreign molecules such as drugs or short DNA fragments need to be transported into the cell. Electroporation is a technique used to increase the permeability of the membrane transi ently by treating the cell with short electrical pulses. Which statement most likely explains how electroporation works? A The short electrical pulses denature the membrane proteins, allowing foreign molecules to pass through. B The short electrical pulses cause the foreign molecules to be attracted to the surface of the membrane. C Electricity increases the hydrophobic nature of foreign molecules, allowing them to pass through the hydrophobic core of the phospholipid bilayer. D Electroporation causes the phospholipids to move apart to create pores for foreign molecules to pass through. 8 During the mitotic cell cycle, the chromosomal DNA is replicated. The specific points in D NA molecules where replication is occurring are known as replication forks. A typical human chromosome has about 150 million base pairs of DNA. It takes about 1 hour to replicate the DNA of a typical human chromosome. The rate of replication using a single replication fork is approximately 50 base pairs per second. Approximately how many replication forks must occur in a typical human chromosome du ring DNA replication? A 835 B 41 700 C 50 000 D 3 000 000 9 Which statement(s) is/are not true in all eukaryotes? 1. Polypeptides are only synthesized in the cytosol. 2. Amino acids are linked by the formation of peptide bonds catalysed by a ri bozyme. 3. Ribosomes contain an amino-acyl tRNA site that is occupied by the initiator tRNA attached to methionine. 4. Amino-acyl tRNA synthetase attaches an amino acid to the 5 ’ end of a tRNA molecule. A 1 and 4 only B 2 and 3 only C 1, 3 and 4 D 2, 3 and 4

6 ©EJC 2024 9744/01/J2H2PRELIM/2024 10 A mutation of a gene coding for an ion pump in cell surface membranes results i n the substitution of one amino acid, arginine, by another, histidine. The DNA triplet codes for the two amino acids are shown. Arginine GCA Histidine GTA GCG GTG GCT GCC TCT TCC Which mutation has occurred in the DNA? A addition of an extra nucleotide B replacement of a nucleotide with a purine base by one with a different purine base C replacement of a nucleotide with a purine base by one with a pyrimidine base D replacement of a nucleotide with a pyrimidine base by one with a different pyrimidine base 11 The diagram shows the mitotic cell cycle. During which phase do chromosomes condense and become visible?

7 ©EJC 2024 9744/01/J2H2PRELIM/2024 [Turn over 13 Chromosomal aberrations cause mutations in cancer-critical genes which may lead to uncontrolled cell division. The following statements describe some possible chromosomal aberrati ons and their consequences. 1. Formation of a hybrid gene resulting in hyperactive protein, leading to chronic m yeloid leukemia. 2. Gene deletion resulting in retinoblastoma. 3. Translocation in a chromosome region resulting in melanoma. 4. Loss of chromosomal regions in solid tumour cells. 5. Amplification of a chromosomal region in many sarcomas. Which statements describe chromosomal aberrations that affect proto-oncogenes and tumou r suppressor genes respectively? proto-oncogenes tumour suppressor genes A 1, 2 3, 4, 5 B 2, 3, 4 1, 5 C 4, 5 1, 2, 3 D 1, 3, 5 2, 4 12 Which are correct statements about the need for a reduction division? 1 Reduction division needs to occur so that a parent will contribute to the zygote one set of chromosomes that are similar in size and number to the set contributed by the o ther parent and contain the same genes, but not necessarily the same alleles. 2 There is a requirement to reduce the diploid number of chromosomes, characteristic o