2019 EJC Promo JC1 P1 Bio (A)

©EJC 2019 9744/01/J1H2PROMO/2019 [Turn over EUNOIA JUNIOR COLLEGE JC1 Promotional Examinations 2019 General Certificate of Education Advanced Level Higher 2 H2 Biology Paper 1 Multiple Choice 9744/01 04 October 2019 1 hour Additional Materials: Multiple Choice Answer Sheet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use paper clips, glue or correction fluid. Write your name, civics group and registration number on the Answer Sheet in the spaces provided. There are thirty Multiple Choice 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 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 document consists of 23 printed pages and 1 blank page.

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3 ©EJC 2019 9744/0J1H2PROMO/2019 [Turn over 1 The following diagrams show short sections of some common polysaccharides and modified polysaccharides. 1 2 3 4 The four polysaccharides P, Q, R and S are described as follows: • Polysaccharide P is composed of β-glucose monomers with 1,4 glycosidic bonds. • Polysaccharide Q is composed of α-glucose monomers with 1,4 and 1,6 glycosidic bonds. • Polysaccharide R is composed of α-glucose monomers with 1,4 glycosidic bonds. • Polysaccharide S is composed of N-acetylglucosamine monomers with β-1,4 glycosidic bonds. Which row correctly pairs the polysaccharide with its structure? Polysaccharide P Q R S A 2 4 3 1 B 2 4 1 3 C 3 1 2 4 D 3 4 1 2 O H H O H O H O H H O H O H O H O H O H O H OH H CH2OH O OH C H O H H H O H O H OH H CH2OH O NHCOCH3 C H O H H H NHCOCH3

4 ©EJC 2019 9744/01/J1H2PROMO/2019 2 Chromatography is a technique used to separate molecules by their solubility. The diagram shows an apparatus used for this technique. As the solvent rises up the paper, the molecules with the greatest solubility in the solvent travel the greatest distances up the paper. When the solvent reaches the top of the paper, the paper is removed, dried and sprayed with a dye. The different molecules appear as coloured spots Chromatography was carried out on four different samples – lactose, cellulose, as well as the products of complete hydrolysis of lactose and cellulose. The diagram below shows the results for each sample. Which row correctly identifies the chromatogram of each sample? lactose cellulose hydrolysed lactose hydrolysed cellulose A 4 3 1 2 B 3 4 2 1 C 1 2 3 4 D 2 1 4 3 1 2 3 4

5 ©EJC 2019 9744/0J1H2PROMO/2019 [Turn over 3 Phosphatidylcholines make up a large proportion of phospholipids in red blood cell membranes. They are phospholipids that have choline as part of their polar head section, as shown in the diagram below. Four different phospholipases, A 1, A2, C and D, act on different parts of the phosphatidylcholine molecule as indicated. It is known that 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. The table shows the four most abundant fatty acids that form part of phosphatidylcholines. fatty acid molecular formulae 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 Which statement about phospholipase action on isolated phosphatidylcholines is correct? A The action of phospholipase A1 is likely to yield a higher proportion of oleic acid than stearic acid. B The action of phospholipase A 2 is likely to yield a higher proportion of linoleic acid than palmitic acid. C The action of phospholipase A1, A2 and D will cause an increase in the pH of the reaction medium. D The products of the combined action of phospholipases A1, A2 and D will be free fatty acids, glycerol and choline. choline

6 ©EJC 2019 9744/01/J1H2PROMO/2019 4 Approximately half of the total protein in a pea seed consists of the storage protein vicillin. • Each molecule of vicillin is made up of three identical polypeptide chains. • Each polypeptide is made up of two β-pleated sheet regions with linking α -helix regions, folded into the shape shown in Fig 4A. • This allows the three polypeptides to pack together into a compact, flat storage molecule, as shown in Fig 4B. Which row correctly describes the structure of vicillin? primary structure secondary structure tertiary structure quaternary structure A sequence of mRNA codons coding for each polypeptide amino acid sequence of one polypeptide α-helix and β- pleated sheet regions of each polypeptide further folding of each polypeptide B amino acid sequence of one polypeptide α-helix and β- pleated sheet regions of each polypeptide association of three polypeptides further folding of each polypeptide C amino acid sequence of one polypeptide α-helix and β- pleated sheet regions of each polypeptide further folding of each polypeptide association of three polypeptides D sequence of mRNA codons coding for each polypeptide amino acid sequence of one polypeptide α-helix and β- pleated sheet regions of each polypeptide association of three polypeptides Fig 4A Fig 4B

7 ©EJC 2019 9744/0J1H2PROMO/2019 [Turn over 5 The diagram below shows the structures of two amino acids that are found in a globular protein. When placed in an aqueous medium, where are these amino acids most likely to be found? A Both serine and alanine will be found in the interior of the globular protein. B Both serine and alanine will be found on the exterior of the globular protein. C Alanine will be found on the exterior, and serine in the interior of the globular protein. D Alanine will be found in the interior, and serine on the exterior of the globular protein. 6 A student investigated the hydrolysis of lipids in a sample using the enzyme lipase. These lipids consist of triglycerides with short-chain hydrocarbons between 1 to 5 carbons in length. • 1 cm3 of lipase solution was added to 4 cm3 of liquid sample at a range of temperatures. • At each temperature, the ethanol-emulsion test was conducted after 10 minutes. • The absorbance of the resulting mixture was measured using a spectrophotometer. • Distilled water gives an absorbance reading of 0 arbitrary units. • All other variables were kept constant. Which graph shows the effect of increasing temperature on absorbance? serine alanine absorbance / a.u. absorbance / a.u. absorbance / a.u. absorbance / a.u. D

8 ©EJC 2019 9744/01/J1H2PROMO/2019 7 Malic acid is produced by a series of enzyme-catalysed reactions. oxoglutaric acid enzyme 1 �⎯⎯⎯⎯⎯� succinic acid enzyme 2 �⎯⎯⎯⎯⎯� fumaric acid enzyme 3 �⎯⎯⎯⎯⎯� malic acid A beaker was set -up with oxoglutaric acid and enzymes 1, 2, and 3. The addition of malonic acid results in changes to the concentrations of other intermediates and products as shown in the graph below. Further addition of fumaric acid results in the formation of malic acid. What does the above information indicate about malonic acid? A It is a competitive inhibitor of enzyme 1. B It is a competitive inhibitor of enzyme 2. C It reacts with