SAJC 2023 H2 BIO P1 QP

Civics Group Index Number Name (use BLOCK LETTERS) ST. ANDREW’S JUNIOR COLLEGE 2023 JC2 PRELIMINARY EXAMINATIONS H2 BIOLOGY 9744/01 Paper 1: Multiple Choice Monday 18th September 2023 1 hour Additional Materials: Multiple Choice Answer Sheet (OTAS) READ THESE INSTRUCTIONS FIRST Do not open this booklet until you are told to do so. Write your name, civics group and index number on the multiple choice answer sheet in the spaces provided. There are 30 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 multiple choice Optical answer sheet. INFORMATION TO CANDIDATES Each correct answer will score one mark. A mark will not be deducted for wrong answer. Any rough working should be done in this booklet. At the end of the examination, submit both question paper and multiple choice answer sheet. This document consists of 22 printed pages [Turn over] H2

2 SAJC / H2 Biology 9744/1 JC2 Prelim 2023 Answer all questions 1 A new fossil unicellular organism was discovered in rocks 150 million years old. Scientists studied the cell structure of several samples under the electron microscope. Which features suggest it was a eukaryote and not a prokaryote? 1 The nucleus was enclosed by a nuclear envelope with nuclear pores and contained two nucleoli. 2 The cisternae of rough endoplasmic reticulum were covered with ribosomes. 3 Oval organelles 1-2 μm long, in which the inner membrane was folded. 4 The cell wall was an extracellular structure, oval in shape. A 1 and 2 only B 1 and 4 only C 1, 2 and 3 only D 2 and 3 only 2 The following are a series of organic molecules and the chemical processes that occur to convert them into different molecules. Which of the rows, A to D, is correct?

3 SAJC / H2 Biology 9744/1 JC2 Prelim 2023 3 The graphs show the rate of uptake of sugars by a culture of animal cells, under different conditions. How are the sugars taken up by the cells when air is bubbled through the culture? 3-carbon sugar 6-carbon sugar A active transport active transport B active transport diffusion C diffusion active transport D diffusion diffusion

4 SAJC / H2 Biology 9744/1 JC2 Prelim 2023 4 The figure shows the metabolic pathways leading to synthesis of five amino acids: aspartate, lysine, methionine, threonine and isoleucine. E1 to E8 represent different enzymes involved in these pathways. Which of the options is an example of end-product inhibition? A aspartate inhibits E3 and E4 B lysine inhibits E1 and E6 C isoleucine inhibits E7 D methionine inhibits E8

5 SAJC / H2 Biology 9744/1 JC2 Prelim 2023 5 Down’s syndrome can be caused by a trisomy of chromosome 21, but can also result from translocation of chromosome 21 onto chromosome 13, forming a single chromosome 13-21. The diagram shows chromosomes 13 and 21 in the nucleus of a diploid (2n) testis cel l from a phenotypically normal male carrier of a 13-21 translocation. This cell has a chromosome number of 45. Which is not a likely outcome of fertilisation of normal oocytes by sperm from this male? chromosomes in sperm embryo A 13 and 21 2n = 46 normal phenotype B 13–21 2n = 45 normal phenotype C 13–21 and 21 2n = 46 Down’s syndrome D 13–21 and 21 2n = 47 Down’s syndrome 6 Which of the following statements is/are evidence that DNA replication is semi-conservative? 1 After one replication, the number of adenine nucleotides is equal to the number of guanine nucleotides. 2 After two replications, two DNA molecules have one original and one new strand, and two DNA molecules have two new strands. 3 After three replications, there are eight DNA molecules, only two of which have strands from the original DNA. A 1, 2 and 3 B 1 and 2 only C 2 and 3 only D 1 only

6 SAJC / H2 Biology 9744/1 JC2 Prelim 2023 7 The table shows the DNA triplet codes for some amino acids. The base sequence on the DNA template strand coding for part of a polypeptide is shown. CCA TTC ACG GCG TTA GCA Two mutations occur in this sequence during DNA replication. Which mutated DNA would result in a polypeptide with one different amino acid? A CCA ATC ACG GCG TTG GCA B CCA TTC ACA GCA TTA GCA C CCA TTC ACG CCG TTA GCC D CCT TTC ACG GCG TTA GCC

7 SAJC / H2 Biology 9744/1 JC2 Prelim 2023 8 A student wrote three statements about cell signalling. 1 A signal chemical always has the same shape as a protein receptor on a target cell. 2 An increase in temperature may decrease the effect of cell to cell signalling. 3 A mutation may decrease production of active protein receptors for the cell surface membrane. Which statements are correct? A 1, 2 and 3 B 1 and 3 only C 1 only D 2 and 3 only 9 What are the conditions in a human cell just before the cell enters prophase? number of chromatids number of molecules of DNA in nucleus spindle present nuclear envelope present A 46 46 yes no B 92 46 no yes C 46 92 yes yes D 92 92 no yes 10 What do the causative agents of HIV/ AIDS, malaria and TB have in common? cell surface membrane genome ribosomes respiration A     B     C     D    

8 SAJC / H2 Biology 9744/1 JC2 Prelim 2023 11 Which of the following statement(s) on viruses is/are true? 1 The HIV polyprotein undergoes cleavage to form functional proteins during post- transcriptional processing. 2 Replication of both HIV and lambda phage have a latent phase. 3 The specific transfer of genes from one bacterial strain to another by a T4 phage occurs during specialized transduction. 4 Influenza virus undergoes genetic drift as there is an accumulation of mutations in the haemagglutinin gene with time. A 2 only B 1 and 3 C 1 and 4 D 2 and 4 12 What is present in all viruses? A ribose B deoxyribose C adenine D thymine

9 SAJC / H2 Biology 9744/1 JC2 Prelim 2023 13 The diagram shows 50 kb segments of the human, E.coli and Zea mays genomes. Which one of the following statements can be concluded from the above results showing the genetic organisation of a 50 kb portion of the human, E.coli and Zea mays genomes? A More complex organisms have lower gene density. B Zea mays has a higher density of DNA repeats as compared to humans and E. coli. C Organisms with smaller chromosome number have higher gene density. D The presence of introns in DNA of eukaryotes allows alternative splicing to occur to synthesise as many proteins as prokaryotes.

10 SAJC / H2 Biology 9744/1 JC2 Prelim 2023 14 An experiment was conducted to determine the effects of a novel promoter on the transcription of a gene. The cloned promoter was ligated to luciferase, a reporter gene which when expressed allows the amount of proteins to be quantified by colorimetry. Several regions of DNA in the promoter region were deleted and the construct transformed into cells and the luciferase activity measured. The data from the experiment is shown in the following table. DNA region deleted Relative luciferase expression No deletion 100 A 320 B 100 C 15 D <1 What conclusion can be drawn from the data? A Region D does not contain any control elements. B Enhancers that increase transcription are located in region A. C Expression of the gene is reduced when region C is deleted because silencers are deleted. D Repressor binding sites are located in region A.