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Civics Group Index Number Name (use BLOCK LETTERS) ST ANDREW’S JUNIOR COLLEGE 2021 JC1 Final Year Examination H1 BIOLOGY 8876/2 Paper 1 & 2: Tuesday October 2021 1hr 45min READ THESE INSTRUCTIONS FIRST Write your name, civics group and index number on all the work you hand in. Write in dark blue or black pen on both sides of the paper. You may use a soft pencil for any diagram, graph or rough working. Do not use staples, paper clips, highlighters, glue or correction fluid. Section A (Multiple Choice Questions) Answer all 10 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 answer sheet (OTAS). Sections B and C (Structured Questions + Essay) Answer the all 5 questions. Write your answers in the blanks provided. INFORMATION TO CANDIDATES At the end of the examination, 1. Submit the OTAS and question paper separately. Conceptual mistake (C) Expression (E) Data Quoting (D) Misreading the question (Q) For Examiner’s Use Section A /10 Section B 1 /10 2 /10 3 /10 4 /10 Section C 5 /10 Total /60 This document consists of XX printed pages. [Turn over H1

1 SAJC / 9744 / H2 Biology / Final Year Examination 2021 Section A Shade your answers in the OTAS provided. 1 The figure below shows an electron micrograph of a cell. Which row correctly describes structures P – R? P (RER) Q (Mitochondrion) R (nucleus) A synthesis of ribosomes (X) substrate level phosphorylation (true – Krebs cycle occurs in mitochondrion) active replication of genes B provision of large surface area for attachment of ribosomes formation of ATP from light energy (X) active transcription of genes C synthesis of membrane proteins oxidative decarboxylation active transcription of genes

2 SAJC / 9744 / H2 Biology / Final Year Examination 2021 D transport of proteins to Golgi apparatus modification of mRNA transcripts (X) circular DNA in mitochondria, similar to bacterial genes, no post- transcriptional modifications active replication of genes 2 The following are all observations about cell surface membranes. 1 Phospholipids labelled with radioactive phosphate groups change position over time. (√) 2 Proteins labelled with fluorescent dyes change position over time. (√) 3 Lectins are proteins that bind to polysaccharides. They only attach to the outside of membrane samples. (X) This only describes how the membrane is asymmetrical (i.e. inner surface not the same as outer surface). 4 Electron microscope images of membranes fractured b y freezing show a large number of regularly arranged particles interrupted by larger particles. (√) demonstrates the scattered arrangement of proteins in the layer of phospholipids. 5 Some membranes contain more cholesterol and unsaturated fatty acid chains than other membranes. (X) This describes different compositions of membranes but not fluid mosaic. 6 Some proteins can only be separated from the membrane by disrupting the membrane with detergent. (X) This describes how proteins are embedded in the membrane by hydrophobic interactions between their non - polar R groups and the hydrocarbon chains of the phospholipid bilayer. Which observations provide evidence for the fluid mosaic model of cell surface membranes? “Fluid” refers to phospholipids and proteins being able to move, and “mosaic” refers to the random, scattered arrangement of the proteins in the membrane. A 1, 2 and 4 B 1, 2 and 6 C 3, 4 and 5 D 3, 5 and 6

3 SAJC / 9744 / H2 Biology / Final Year Examination 2021 3 The following diagram show different types of bond found in biological molecules. Which combination of bonds could not be found in a protein with a tertiary structure? A 1, 2, 3 and 4 B 1, 2 and 4 C 3 and 5 D 5 only Consists of hydrogen bond, ionic bond, disulphide bond, hydrophobic interaction (all found in tertiary structure) and peptide bond (found in primary structure) 4 The flowchart outlines the process of anaerobic respiration in yeast cells. Which of the statements regarding the identities of the compounds is not correct? A Compound W can also be synthesised in the anaerobic respiration of plant cells. B Compound X is a waste product. C Compound Y is necessary for more rounds of glycolysis. D Compound Z acts as an oxidising agent Hydrogen bond Disulfide bond Peptide bond Ionic bond Ether bond Ethanal/ acetylaldehyde Carbon dioxide NADH NAD+

4 SAJC / 9744 / H2 Biology / Final Year Examination 2021 5 The graph below shows the change in the concentration of RuBP and glycerate phosphate in the presence of light and when the light is switched off. Which statement(s) is/are true? 1 In the dark, the amount of glycerate phosphate increased initially due to the lack of reduced NADP. Yes, in the dark no ATP and NADPH is produce for reducing step. 2 In the dark, the amount of glycerate phosphate increased initially a s more RuBP is converted to glycerate phosphate. Yes, in the dark no ATP and NADPH is produce for reducing step but CO 2 fixation can still occur. 3 In the dark, the amount of RuBP decreased initially as it reacted with carbon dioxide. Yes, in the dark no ATP and NADPH is produce for reducing step but CO2 fixation can still occur so RuBP decreased 4 In the light, the concentration of RuBP and glycerate phosphate were constant as RuBP that was used to form glycerate phosphate was regenerated. Yes, 10 out of 12 PGAL is used to regenerate RuBp while the other 2 forms glucose A 1 and 2 B 1, 3 and 4 C 2, 3 and 4 D 1, 2, 3 and 4

5 SAJC / 9744 / H2 Biology / Final Year Examination 2021 6 A simplified representation of a replication bubble is shown in the figure below. Parental strands 1 and 2 and the growing daughter strands X and Y are indicated. Which of the following statements about the synthesis of daughter strands X and Y is correct? A Daughter strands X and Y are synthesised away from their respective replication forks. Strand Y is synthesised towards the replication fork due to the presence of a free 3’ OH group. B Daughter strand X is synthesised continuously while daughter strand Y is synthesised in the form of Okazaki fragments. The opposite is true. C Daughter strand X is synthesised in the 5’ → 3’ direction while daughter strand Y is synthesised in the 3’ → 5’ direction. Both strands are synthesised from 5’  3’ direction as DNA polymerase can only add new nucleotides to a free-3’ OH group of an existing strand. D To synthesise daughter strands X and Y, both parental strands 1 and 2 are read in the 3’ to 5’ direction. 7 Bacteria were cultured in a medium containing heavy nitrogen (15N) until all the DNA was labelled. These bacteria ( G0) were then grown in a med ium containing only normal nitrogen (14N) for two more generations (G1 and G2). At each generation, a sample is removed and the DNA is extracted and centrifuged in caesium chloride. If DNA replicates according to the conservative model rather than the sem i- conservative model, which of the following would be the expected results of the experiment? ANSWER: B

6 SAJC / 9744 / H2 Biology / Final Year Examination 2021 Explanation for conservative model: 8 Which of the following are not involved in transcription? 1 Helicase involved in DNA replication 2 Transcription factors 3 DNA polymerase involved in DNA replication 4 Deoxyribonucleotides involved in DNA replication A 1 only B 1 and 3 C 2 and 4 D 1, 3 and 4

7 SAJC / 9744 / H2 Biology / Final Year Examination 2021 9 The following table shows the mRNA codons for six different amino acids. mRNA codons amino acid AAA AAG lysine AGA AGG CGG arginine GGU