2024 NJC H2 Bio P1 QP

©NJC 2024 9744/01/SH2 Preliminary Examination [Turn over H NATIONAL JUNIOR COLLEGE, SINGAPORE Senior High 2 Preliminary Examination Higher 2 CANDIDA TE NAME BIOLOGY CLASS 2bi2_____ REGISTRATION NUMBER Biology Paper 1 Multiple Choice Additional Materials: Multiple Choice Answer Sheet 9744/01 18 September 2024 1 hour READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name, Biology class and registration number on all the work you hand in. 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. Your five-digit OAS index number is made up of the second and last four digits of your registration number. For example: Registration no. OAS Index no. 2205123 25123 This document consists of 20 printed pages.

2 ©NJC 2024 9744/01/SH2 Preliminary Examination 1 The endosymbiotic theory states that eukaryotic mitochondria and chloroplasts originated from ancestral prokaryotes. Which statements support this theory? 1 The smallest eukaryotic cells are the same size as many bacteria. 2 Eukaryotic cells and prokaryotic cells both have ribosomes free in the cytoplasm. 3 Human mitochondrial DNA is circular and contains no introns. 4 Chloroplasts divide by binary fission, independently of the plant cell. A 1, 2 and 3 only B 1 and 3 only C 1 and 4 only D 3 and 4 only 2 The diagram shows the structure of a bacterium. Which row correctly identifies the labelled structures? P Q R S A 70S ribosomes plasma membrane cellulose cell wall single-stranded DNA B 80S ribosomes plasma membrane cellulose cell wall double-stranded DNA C 70S ribosomes plasma membrane peptidoglycan cell wall double-stranded DNA D 80S ribosomes tonoplast peptidoglycan cell wall double-stranded DNA Q P S R

3 ©NJC 2024 9744/01/SH2 Preliminary Examination [Turn over 3 Raffinose is a trisaccharide that can be digested by enzymes. The table shows the results of two different enzymatic incubations. enzyme used products galactosidase galactose and sucrose sucrase melibiose and fructose Which statements are consistent with the results shown above? 1 Acid hydrolysis of raffinose would yield glucose. 2 Melibiose is a disaccharide. 3 Raffinose is composed of three different monosaccharides. 4 The products of digestion by galactosidase and sucrase will yield a brick red precipitate when heated with Benedict’s reagent. A 1, 2, 3 and 4 B 1, 2 and 3 only C 1 and 3 only D 2 and 4 only 4 The diagram shows how various substances are transported across the membranes of two nerve cells at a synapse. Which statements correctly describe the transport of substances across the membranes? 1 Ions move across the membrane through protein channels via facilitated diffusion. 2 Some ions are actively transported across the membranes by carrier proteins. 3 Some substances may diffuse readily across the membrane. 4 There are at least two transport mechanisms that require energy expenditure. A 1, 2, 3 and 4 B 1, 2 and 3 only C 2, 3 and 4 only D 1 and 2 only

4 ©NJC 2024 9744/01/SH2 Preliminary Examination 5 The diagram shows the action of an enzyme on a substrate. The rates of reaction of this enzyme were studied in the presence and absence of inhibitors. The curves obtained are shown below. What do the curves show? curve 1 curve 2 curve 3 A B C D 3 2 1 substrate concentration rate of reaction

5 ©NJC 2024 9744/01/SH2 Preliminary Examination [Turn over 6 The image shows a micrograph of two different types of blood cell. Both cell types P and Q develop from myeloid stem cells in the bone marrow. Which statement correctly describes myeloid stem cells? A They are both pluripotent and multipotent. B They are multipotent but not pluripotent. C They are neither pluripotent nor multipotent. D They are pluripotent but not multipotent.

6 ©NJC 2024 9744/01/SH2 Preliminary Examination 7 The diagram shows an anticodon. Which row correctly identifies the labelled structures? W X Y A deoxyribose base phosphate B deoxyribose phosphate base C ribose base phosphate D ribose phosphate base 8 Edeine is an antibiotic that inhibits protein synthesis but has no effect on either DNA synthesis or RNA synthesis. When added to a translation mixture containing fully intact organelles, edeine stops haemoglobin synthesis after a short period of time. Analysis of the edeine -inhibited mixture by centrifugation showed that all the mRNA accumulated, together with small ribosomal subunit and initiator tRNA. What step in protein synthesis does edeine inhibit? A It blocks the translocation of aminoacyl -tRNA from the A -site to the P -site of the ribosome. B It inhibits the binding of aminoacyl-tRNA to the A-site in the ribosome. C It interferes with chain termination and release of peptide. D It prevents the formation of the translation initiation complex, which contains the initiator tRNA and both large and small ribosomal subunits.

7 ©NJC 2024 9744/01/SH2 Preliminary Examination [Turn over 9 A virus has a base ratio of (A + G) / (U + C) = 1. What type of virus is this? A a double-stranded DNA virus B a single-stranded DNA virus C a double-stranded RNA virus D a single-stranded RNA virus 10 Human immunodeficiency virus (HIV) is a retrovirus. After infecting a host cell, viral DNA is produced and then incorporated into the DNA of the host cell. The modified host genome now codes for the production of new HIV particles. Which inhibitor(s) could be used as a potential treatment to slow down the spread of HIV? 1 inhibitor of integrase 2 inhibitor of neuraminidase 3 inhibitor of RNA-dependent DNA polymerase 4 inhibitor of RNA-dependent RNA polymerase A 1 and 3 only B 2 and 4 only C 1 only D 3 only 11 Which row incorrectly describes a difference between generalised and specialised transduction? generalised transduction specialised transduction A Donor DNA is hydrolysed into pieces upon entry of phage genome. Donor DNA is not hydrolysed immediately into pieces upon entry of phage genome. B Phage DNA is not integrated into the host chromosome. Phage DNA is integrated into the host chromosome. C Random donor DNA is transferred. Specific donor DNA is transferred. D Transducing phage contains phage DNA. Transducing phage does not contain phage DNA.

8 ©NJC 2024 9744/01/SH2 Preliminary Examination 12 Mutant Escherichia coli were grown in a medium without glucose and lactose. It was observed that the lac structural genes were expressed efficiently. Which mutation(s) is/are present in the mutant E. coli? 1 a mutation in the lacI gene 2 a mutation in the lac operator 3 a mutation in the lac promoter A 1 and 2 only B 2 and 3 only C 1 only D 2 only 13 A length of DNA contains a non-coding region, PQ and a coding region, QR. The effect of removing parts of the non-coding region on the coding region was investigated. The diagram shows the results of removing PS and then ST. Which conclusion may be deduced from these results? A The removal of any DNA from the non-coding region affects transcription. B The beginning of the promoter region is between P and S. C The beginning of the promoter region is between S and T. D The non-coding region has no role in transcription.

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