2023 EJ P1 Bio Prelim

©EJC 2023 9744/01/J2H2PRELIM/2023 [Turn over EUNOIA JUNIOR COLLEGE JC2 Preliminary Examination 2023 General Certificate of Education Advanced Level Higher 2 H2 Biology Paper 1 Multiple Choice 9744/01 22 September 2023 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 22 printed pages and 2 blank pages.

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3 ©EJC 2023 9744/01/J2H2PRELIM/2023 [Turn over Answer all questions. 1 Disaccharides are formed following synthesis from monosaccharides or as a result of polysaccharide hydrolysis. Cellobiose, maltose, sucrose and trehalose are four different disaccharides found in nature. Some features of these disaccharides are listed. • Cellobiose is formed from the hydrolysis of the polysaccharide cellulose. • Sucrose is composed of glucose and fructose. • Trehalose is a non -reducing disaccharide that is synthesised from two α -glucose molecules. • Maltose is formed from the hydrolysis of amylose, a component of starch. Which column correctly identifies each disaccharide? A B C D cellobiose maltose sucrose trehalose maltose cellobiose trehalose maltose sucrose trehalose cellobiose cellobiose trehalose sucrose maltose sucrose

4 ©EJC 2023 9744/01/J2H2PRELIM/2023 2 When hydrolysed, which molecules have products containing carboxyl groups? 1 phospholipids 2 polysaccharides 3 proteins A 3 only B 1 and 2 C 1 and 3 D 2 and 3 3 How many different polypeptides, each of 100 amino acids, can be made if the number of different amino acids available is 10? A 10010 B 10100 C 1000 D 10 4 The curve X shows the activity of an enzyme at 20 °C. Curves A, B, C and D show the effect of different conditions on the activity of the enzyme. Which curve shows the effect of increasing the temperature by 10°C and adding extra substrate? A B C D amount of product time

5 ©EJC 2023 9744/01/J2H2PRELIM/2023 [Turn over 5 A scientist carried out an experiment to separate the organelles in an animal cell by density. The scientist mixed the cells with a buffer solution which had the same water potential as the cells. The cells were lysed with a blender to release the organelles. The mixture was filtered and then spun in a centrifuge at a high speed to separate the heaviest organelle. This sank to the bottom, forming a solid pellet, 1. The liquid above pellet 1 was poured into a clean centrifuge tube and spun in the centrifuge at a higher speed to separate the next heaviest organelle. This organelle sank to the bottom, forming a solid pellet, 2. He repeated this procedure twice more to obtain pellet 3 and pellet 4, each containing a single type of organelle. What is the most likely function of the organelle extracted in pellet 4? A digestion of old organelles B production of mRNA C production of ATP D catalyse bond formation in polypeptides

6 ©EJC 2023 9744/01/J2H2PRELIM/2023 6 Studies have shown that the formation of stable flattened stacks of membranes are essential for the proper functioning of the Golgi body . This structure is maintained by a microtubule network and a group of peripheral and integral proteins found on the cytoplasmic surface of Golgi membranes. In some diseases, such as certain types of cancer and some neurodegenerative diseases, the structure of the Golgi body is fragmented as shown in the diagram below. The fragments are unlinked and are dispersed in the cytoplasm of the cell. Which statements are possible inferences from the given information? 1 Fragmented Golgi bodies contain non -functional glycosyltransferases, which results in hyperactive glycoproteins linked to cancer. 2 Fragmented Golgi bodies are a consequence of mutated Golgi membrane proteins, resulting in the loss of attachment sites for cisternae to stack. 3 Fragmented Golgi bodies may result in the loss of attachment sites for transport vesicles from the rough en doplasmic reticulum, leading to unmodified proteins which are non - functional. 4 Fragmented Golgi bodies may result in reduction of sorting and processing of proteins for the maintenance of nerve cells, leading to their degeneration. A 4 only B 1 and 2 only C 2, 3 and 4 only D 1, 2, 3 and 4 normal Golgi body fragmented Golgi body

7 ©EJC 2023 9744/01/J2H2PRELIM/2023 [Turn over 7 Graph A shows the transport of molecule X, with the help of carrier proteins, over time. A student predicted that the alteration of one variable would result in graph B. Which row shows the correct transport process and the correct alteration in variable that would result in graph B? Transport process Alteration resulting in graph B A facilitated diffusion increase in concentration of X outside cells B active transport increase in concentration of X in cells C facilitated diffusion increase in number of carrier proteins D active transport increase in environmental temperature to 90°C 8 If DNA synthesis is initiated at the indicated origin of replication as shown in figure below. Which segments of single-stranded DNA are templates for the synthesis of Okazaki fragments? A R and U B S and T C R and T D S and U

8 ©EJC 2023 9744/01/J2H2PRELIM/2023 9 An antibiotic, edeine, was isolated. It inhibits protein synthesis but has no effect on either DNA synthesis or RNA synthesis. When added to a mixture containing fully intact organelles, edeine stops translation after 10s. Analysis of the edeine -inhibited mixture showed that no polyribosomes re mained by the time protein synthesis had stopped. Instead, all the mRNA accumulated together with small ribosomal subunit and initiator tRNA. What step in protein synthesis does edeine inhibit? A It interferes with chain termination and release of the peptide. B It inhibits the binding of amino acyl-tRNAs to the A-site in the ribosome. C It blocks the translocation of peptidyl-tRNA from the A-site to the P-site of the ribosome. D It prevents the formation of the translation initiation complex, which contains the initiator tRNA and both ribosomal subunits. 10 The codons UGU and UGC code for the amino acid cysteine, which can form disulfide bonds in a polypeptide. The codon UGG codes for the amino acid tryptophan, which does not contain a sulfur atom. UGA is a stop codon. On the template DNA strand, the DNA triplet code for the 10th amino acid in a particular polypeptide is ACA. Which single base substitution(s) in this triplet code will result in no disulfide bond being formed with the 10th amino acid in the polypeptide? A ACC and ACG B ACG and ACT C ACT and ACC D ACG only

9 ©EJC 2023 9744/01/J2H2PRELIM/2023 [Turn over 11 The graphs show various measurements taken from mitotic stages of metaphase and beyond . The graphs are all to the same scale. Which row correctly describes each graph? X Y Z A dista