2017 HCI H2 Biology Prelims Paper 1 Questions

© Hwa Chong Institution 2017 9744 H2 Biology / JC2 Preliminary Examinations / Paper 1 HWA CHONG INSTITUTION JC2 Preliminary Examinations Higher 2 CANDIDATE NAME CT GROUP 16S7___ CENTRE NUMBER INDEX NUMBER BIOLOGY Paper 1 Multiple Choice Questions Additional Materials: Optical Mark Sheet 9744/01 21 September 2017 1 hour INSTRUCTIONS TO CANDIDATES 1. Write your name and CT group in the spaces provided at the top of this cover page. 2. Fill in your particulars on the Optical Mark Sheet. Write your NRIC number and shade accordingly. 3. There are thirty 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 Optical Mark Sheet. 4. At the end of the paper, you are to submit only the Optical Mark Sheet. INFORMATION FOR CANDIDATES 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 used of an approved scientific calculator is expected, where appropriate. This document consists of 24 printed pages.

2 © Hwa Chong Institution 2017 9744 H2 Biology / JC2 Preliminary Examinations / Paper 1 1 The diagram shows a single-celled organism with structures P to S labelled. Which statement(s) correctly describes the structures P to S? 1 Structure P is double membranous with infoldings called cisternae and functions in metabolism of glucose. 2 Structure Q is double membranous with flattened sacs called cristae and functions to modify and package products of the endoplasmic reticulum. 3 Structure R is composed of phospholipids, proteins and carbohydrates and functions to prevent cell lysis. 4 Structure S is composed of microtubules and provides cell motility. A 3 only B 4 only C 1 and 4 D 2 and 3 2 Viruses are a major class of microorganisms, but they are not cells. Which statement about viruses supports the view that viruses are not cells? 1 Viruses are very small in size. 2 Viruses are only able to replicate in a host cell. 3 Viruses have no metabolic activities of their own. 4 Viruses have protein capsids. 5 Viruses contain only a single form of nucleic acid. 6 Viruses can evolve by genetic recombination. A 1, 2 and 3 B 1, 5 and 6 C 2, 3 and 5 D 3, 4 and 6 P Q R S

3 © Hwa Chong Institution 2017 9744 H2 Biology / JC2 Preliminary Examinations / Paper 1 3 The graphs show the rate of uptake of suga rs by a culture of animal cells under different conditions. Which statements correctly describe the uptake of sugars by the animal cells? 1 3-carbon sugar passes through the phospholipid bilayer down a concentration gradient. 2 3-carbon sugar passes through channel proteins against a concentration gradient. 3 6-carbon sugar passes through carrier proteins against a concentration gradient. 4 6-carbon sugar passes through the phospholipid bilayer down a concentration gradient. A 1 and 3 B 2 and 3 C 2 and 4 D 1 and 4 oxygen gas bubbled through the culture nitrogen gas bubbled through the culture 3-carbon sugar 6-carbon sugar 3-carbon sugar 6-carbon sugar rate of uptake 0 rate of uptake 0 0 10 20 0 10 20 30 30 temperature / °C temperature / °C

4 © Hwa Chong Institution 2017 9744 H2 Biology / JC2 Preliminary Examinations / Paper 1 4 - and -amylase enzymes can break the -,4-glycosidic bonds of polysaccharides, but not the -1,6-glycosidic bonds. -amylase acts randomly within polysaccharides and can produce glucose, maltose, trisaccharides and short, branched chains. -amylase acts at the ends of polysaccharides to remove successive maltose molecules. Which statement about polysaccharide digestion is correct? A Both -amylase and -amylase are required for the complete digestion of starch to produce only glucose molecules. B Digestion of amylose by -amylase will produce only branched molecules. C Digestion of amylose using -amylase will yield a higher proportion of disaccharides than digestion using -amylase. D Disaccharides can be produced from the digestion of cellulose using -amylase, but not using -amylase.

5 © Hwa Chong Institution 2017 9744 H2 Biology / JC2 Preliminary Examinations / Paper 1 5 Phosphatidylcholines are phospholipids that have choline as part of the polar head section. A high proportion of phospholipids in erythrocyte ( red blood cell ) membranes are phosphatidylcholines. The table shows the results of an analysis to determine the four most abundant component fatty acids of human erythrocyte phosphatidylcholines. fatty acid molecular formula palmitic acid C16H32O2 CH3(CH2)14COOH linoleic acid C18H32O2 CH3(CH2)4(CH=CHCH2)2(CH2)6COOH oleic acid C18H34O2 CH3(CH2)7CH=CH(CH2)7COOH steric acid C18H36O2 CH3(CH2)16COOH The diagram shows a phosphatidylcholine. The site of action of four different phospholipases, A1, A2, C and D, are indicated. In phosphatidylcholines,  saturated fatty acids are more commonly found in position R 1 than unsaturated fatty acids, and  unsaturated fatty acids are more commonly found in position R 2 than saturated fatty acids. Which statement about enzyme action on isolated eryt hrocyte phosphatidylcholines is correct? A The action of phospholipase A 1 is likely to yield a higher proportion of oleic acid than stearic acid. B The action of phospholipase A2 is likely to yield a higher proportion of linoleic acid than palmitic acid. C The products of the combined action of phospholipases A 1, A2 and D will be free fatty acids, glycerol and choline. D The action of phospholipases A 1, A 2 and C will cause an increase in the pH of the reaction medium. choline

6 © Hwa Chong Institution 2017 9744 H2 Biology / JC2 Preliminary Examinations / Paper 1 6 Isocitrate dehydrogenase catalyses the following reaction in the Krebs cycle: isocitrate + NAD+  -ketoglutarate + CO2 + NADH The curves in the graph are obtained when the initial rate of reaction is plotted against isocitrate concentration in the presence of various levels of ADP and excess NAD+. Which statement about this system is correct? A ADP competes with isocitrate for the active site of isocitrate dehydrogenase. B ADP binds to an allosteric site of isocitrate dehydrogenase and prevents binding of isocitrate to the active site. C ADP binds to isocitrate and makes it easier for isocitrate to bind to the active site. D ADP binds to an allosteric site of isocitrate dehydrogenase and makes it easier for isocitrate to bind to the active site. 7 Which is a correct statement about obtaining human embryonic stem cells for research? A Removal of these cells is considered to be ethically acceptable as normal development of the embryo is not inhibited. B The cells must be removed at an early stage of development from a region of the blastocyst known as the inner cell mass. C The cells must be removed within a day following the successful fertilisation of the ovum by the sperm, and after checking for normal mitotic division. D The region of the blastocyst from where the cells are removed is an area that develops at a later stage into the placenta.

7 © Hwa Chong Institution 2017 9744 H2 Biology / JC2 Preliminary Examinations / Paper 1 8 In the classic paper that demonstrated the semi -conservative replication of DNA, scientists Meselson and Stahl began by showing that DNA i