2018 RVHS H2 Biology Prelims Paper 1 Questions

1 River Valley High School Year 6 H2 Biology 9744 Paper 1 2018 Preliminary Examination RIVER VALLEY HIGH SCHOOL YEAR 6 PRELIMINARY EXAMINATION CANDIDATE NAME CENTRE NUMBER S CLASS INDEX NUMBER H2 BIOLOGY 9744/01 Paper 1 Multiple Choice 19 Sep 2018 1 hour Additional Materials: Multiple Choice Answer Sheet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name, Centre number, index number on the Answer Sheet in the spaces provided unless this has been done for you. DO NOT WRITE IN ANY BARCODES. 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 Question Paper consists of 23 printed pages and 1 blank page.

2 River Valley High School Year 6 H2 Biology 9744 Paper 1 2018 Preliminary Examination 1 The diagram shows a typical unicellular prokaryote. Which row correctly describes the labelled structures? 1 2 3 A chromatin cell surface membrane pilus B chromosome cell wall flagellum C chromosome cell wall pilus D plasmid cell surface membrane flagellum 2 Which of the following correctly describes the process of exocytosis? 1 The secretory vesicle diffuses from the trans face of the Golgi apparatus towards the cell surface membrane. 2 Secretory vesicles tend to contain small molecules that cannot pass through the hydrophobic core of the membrane. 3 The membrane of the secretory vesicle fuses with the cell surface membrane, releasing the molecules into the extracellular fluid. A 3 only B 1 and 3 only C 1 and 2 only D All of the above

3 River Valley High School Year 6 H2 Biology 9744 Paper 1 2018 Preliminary Examination 3 The structure of phosphatidylcholine, a common membrane phospholipid, is shown. Which combination correctly describes the synthesis, structure and property of one molecule of phosphatidylcholine? number of water molecules eliminated during synthesis number of ester bonds property A 3 3 amphipathic B 2 2 amphipathic C 2 2 amphoteric D 3 3 amphoteric 4 The following statements describe the four levels of organisation of the structure of haemoglobin. How many of the following statement(s) is true? 1 In primary structure, α and β subunits consist of any number of amino acids joined in a specific sequence by peptide bonds. 2 In secondary structure, the α-helices in each subunit are a result of hydrogen bonding between C=O and N-H groups of regions of the polypeptide backbone that are far apart. 3 In tertiary structure, R group interactions between amino acids allow hydrophilic amino acids to be clustered in the interior of the protein. 4 In quaternary structure, R group interactions between amino acids of different subunits allow for the molecule to exhibit cooperative binding. A 1 B 2 C 3 D 4

4 River Valley High School Year 6 H2 Biology 9744 Paper 1 2018 Preliminary Examination 5 Lactic dehydrogenase catalyses the conversion of la ctic acid to pyruvic acid as shown in the following equation. Two isomers of lactic acid, (-) and (+), are shown below. Reduced NAD absorbs ultraviolet light but NAD does not. The activity of bacterial lactic dehydrogenases on the two different isomers of lactic acid was compared. The absorbance of ultraviolet light was measured using an ultraviolet spectrophotometer. The graphs show the results. What can be concluded about bacterial lactic acid dehydrogenases? A The enzyme is specific to the (-) isomer. B The enzyme is specific to the (+) isomer. C Both isomers fit the active site. D Neither isomer fit the active site.

5 River Valley High School Year 6 H2 Biology 9744 Paper 1 2018 Preliminary Examination 6 Both bacterium Streptococcus salivarius and fungus Aspergillus niger produce enzymes which digest complex sugars. The enzyme produced by A. niger has a higher molecular weight and is encoded by a different gene. How can these enzymes digest the same complex sugars in the same way? A Both enzymes have the same primary structures. B Both enzymes have the same tertiary structures. C The enzyme-substrate complexes formed by both enzymes are identical. D The amino acids forming the active site are the same in both enzymes. 7 Blood transfusion laboratories around the world are hoping to produce large numbers of red blood cells (RBCs) from ‘spare’ human embryos produced during in vitro fertilisation procedures. Embryonic stem cells are removed from an embryo and cultured in a growth medium that stimulates their differentiation into RBCs. Which statement correctly describes this differentiation? A Multipotent embryonic stem cells differentiate into pluripotent blood stem cells and then into RBCs. B Pluripotent embryonic stem cells differentiate into multipotent blood stem cells and then into RBCs. C Totipotent embryonic stem cells differentiate into multipotent blood stem cells and then into RBCs. D Totipotent embryonic stem cells differentiate into pluripotent blood stem cells and then into RBCs. 8 An unknown organism has a linear double-stranded DNA genome like that in a eukaryote. When its DNA replication was examined, it was revealed that although the process is semi- conservative, no Okazaki fragments were observed in the multiple replication forks. In addition, the end-replication problem of shortened daughter strands was not observed. Which statement correctly explains this phenomenon? A The organism’s DNA is antiparallel. B DNA replication only starts at the 3’ end of each template strand. C DNA polymerases synthesise DNA in both 5’ to 3’ and 3’ to 5’ direction. D DNA ligases are not involved in the DNA replication process.

6 River Valley High School Year 6 H2 Biology 9744 Paper 1 2018 Preliminary Examination 9 The diagram shows the synthesis of a polynucleotide. W is a nucleoside triphosphate and the arrows indicate the location where W form bonds with the polynucleotide. Which statements are correct? 1 The base in W could be the purine, adenine. 2 The base in Y is the purine guanine. 3 The base in X is the pyrimidine, cytosine 4 The base in X could be the pyrimidine, uracil A 1 and 3 B 2 and 3 C 2 and 4 D All of the above

7 River Valley High School Year 6 H2 Biology 9744 Paper 1 2018 Preliminary Examination 10 A segment of a polypeptide chain, Arg – Gly – Leu – Phe – Val – Leu – Arg, is encoded by the following segment of DNA: strand 1 3’ G G C A T T C T G C T T A T C T G G G G A 5’ I I I I I I I I I I I I I I I I I I I I I strand 2 5’ C C G T A A G A C G A A T A G A C C C C T 3’ The genetic code (read from inside out) is given below. Which of the following correctly identifies the template strand and mRNA codon? template strand mRNA codon coding for amino acid Leu A strand 1 UUA B strand 1 AUU C strand 2 AUC D strand 2 CUA

8 River Valley High School Year 6 H2 Biology 9744 Paper 1 2018 Preliminary Examination 11 Which of the following are features of a eukaryotic genome? 1 multiple genes are under the control of the same regulatory sequence 2 many genes are interrupted by non-coding sequences 3 presence of multiple control elements for controlling gene expression 4 supercoiling in most regions to further compact the DNA molecule A 1 and 4 B 1 and 3 C 2 and 3 D 2 and 4 12 The foll