Cambridge A Level Biology 9700 — 2016 May/June Paper 2 · Variant 2

This document consists of 15 printed pages and 1 blank page. DC (ST/FD) 109212/3 © UCLES 2016 [Turn over Cambridge International Examinations Cambridge International Advanced Subsidiary and Advanced Level * 2 1 7 0 7 4 5 6 1 4 * BIOLOGY 9700/22 Paper 2 Structured Questions AS May/June 2016 1 hour 15 minutes Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST Write your Centre number, candidate number and name on all the work you hand in. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staples, paper clips, glue or correction fluid. DO NOT WRITE IN ANY BARCODES. Answer all questions. Electronic calculators may be used. You may lose marks if you do not show your working or if you do not use appropriate units. At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question.

2 9700/22/M/J/16 © UCLES 2016 Answer all the questions. 1 Statements A to E are about the structure and functioning of enzymes. State the correct term to match each of the statements A to E. A The energy level, lowered by enzyme action, that needs to be overcome by reactants in order for products to be formed. … B The mechanism of enzyme action that relies on the active site being partially flexible and changing shape in order to bind the substrate. … C The term to describe a protein, such as an enzyme, with a tertiary or quaternary structure that results in an approximately spherical shape. … D The term for enzymes that function outside cells. … E The concentration of substrate that enables an enzyme to achieve half the maximum rate of reaction. … [5] [Total: 5]

3 9700/22/M/J/16 © UCLES 2016 [Turn over 2 Marram grass, Ammophila arenaria, is an important plant of sand dunes. Leaves of marram grass are well adapted to reduce water loss by transpiration. Fig. 2.1 is a photomicrograph of a section though the leaf of marram grass. vascular bundle Fig. 2.1 (a) Examples of adaptations to reduce water loss by transpiration include a thick cuticle and no stomata on the outer surface, and stomata in pits on the inner surface. (i) State one other adaptation, visible in Fig. 2.1, which reduces water loss by transpiration. …[1] (ii) Explain how this adaptation reduces water loss. … … … … … …[2] (b) State the term used to describe a plant type that has adaptations to reduce water loss by transpiration. …[1] [Total: 4]

4 9700/22/M/J/16 © UCLES 2016 3 Globally, measles is an important disease that mainly affects children. Many deaths from measles occur in children under five years of age. Table 3.1 shows the population of six countries in Africa in 2009 and the number of cases of measles per 100 000 people for the four years 2009 to 2012. All six countries are classified as low-income countries. Table 3.1 country population in 2009 number of cases per 100 000 people 2009 2010 2011 2012 Central African Republic 4 266 000 0.26 0.05 15.31 3.12 Chad 11 371 000 1.45 1.66 71.60 0.96 Eritrea 5 558 000 1.48 0.89 0.81 3.16 Ethiopia 84 838 000 1.39 4.86 3.64 4.74 Gambia 1 628 000 0.00 0.12 0.00 0.00 Niger 15 303 000 5.23 2.34 4.67 1.59 (a) (i) The actual number of cases of measles in Chad in 2009 was 165 and in Eritrea was 82. Calculate the actual number of cases of measles in Ethiopia in 2009. Show your working. [2] (ii) Use the data for Chad, Eritrea and Ethopia to explain the advantages of showing the data in Table 3.1 as number of cases of measles per 100 000 people rather than the actual number of cases. … … … … … … … … …[3]

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6 9700/22/M/J/16 © UCLES 2016 Fig. 3.1 shows the percentage of children vaccinated against measles over a ten year period from 2003 to 2012. • The percentage vaccinated represents children under one year of age who have been given at least one dose of the vaccine against measles in the given year. • The data are for the six African countries shown in Table 3.1. 2003 0 10 20 30 40 50 60 70 80 percentage of children vaccinated 90 100 2004 2005 2006 2007 2008 year 2009 2010 2011 2012 Eritrea Gambia Niger Ethiopia Chad Central African Republic Fig. 3.1

7 9700/22/M/J/16 © UCLES 2016 [Turn over (b) Vaccination is known to protect populations against infectious diseases. Some of the data in Table 3.1 (on page 4) and Fig. 3.1 (on page 6) support this statement. Describe the data that support this statement and comment on the data that do not support this statement. … … … … … … … … … … …[4] (c) The successful eradication of smallpox involved an intensive global vaccination programme. It is hoped that the same can be achieved with measles. Outline two features, apart from cost, of the smallpox eradication programme that may have made it easier to eradicate than measles. … … … … … …[2] (d) State precisely the type of immunity gained by receiving a measles vaccine. …[1]

8 9700/22/M/J/16 © UCLES 2016 (e) Planning the prevention and control of measles using a vaccination programme means that financial costs must be considered. State two examples of these costs. 1 … … … 2 … … …[2] [Total: 14] 4 Fig. 4.1 is a simplified diagram of the circulatory system of a mammal. Some of the lymph system is also shown. head and upper limbs lungs kidneys lymph vessels < = ; : 3 4 liver intestines lower limbs Fig. 4.1

9 9700/22/M/J/16 © UCLES 2016 [Turn over (a) The type of circulatory system shown in Fig. 4.1 is a closed double circulation. Explain what is meant by a closed double circulation. … … … … …[2] (b) With reference to Fig. 4.1, name: blood vessel W … blood vessel X … valve Y … heart chamber Z … [4] (c) State the component present in the blood at location P that is not present in the lymph at location Q in Fig. 4.1. …[1] (d) As blood passes through the capillary network in the lungs, gas exchange occurs. Describe the process of gas exchange between the alveolus and the blood. … … … … … … … … … … … …[4]

10 9700/22/M/J/16 © UCLES 2016 (e) As blood passes through the small intestine, small soluble products of digestion such as glucose are absorbed into the capillaries to be transported to the liver. Fig. 4.2 is a transmission electron micrograph of intestinal epithelial cells. 6 ) * JXWOXPHQ GLUHFWLRQRIPRYHPHQWRIJOXFRVHGXULQJDEVRUSWLRQ FDSLOODU\ Fig 4.2 (i) Write the name of cell structures F and G in the boxes provided on Fig. 4.2. [2] (ii) At the surface labelled S, movement of glucose molecules out of the intestinal epithelial cell occurs by facilitated diffusion. Outline the features of facilitated diffusion of glucose molecules. … … … … … … … … …[3] [Total: 16]

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12 9700/22/M/J/16 © UCLES 2016 5 Fig. 5.1 shows plant cells in stages of mitosis. chromosome at metaphase chromosome at late anaphase cell at the start of prophase Fig. 5.1 (a) Individual chromosomes cannot be seen in the cell at the start of prophase. Changes to the chromatin occur so that by late prophase chromosomes are clearly visible. (i) Outline what occurs during early prophase so that chromosomes become visible in late prophase. … … …[1] (ii) Describe the structure of the chromosome in late prophase. … … … … … … …[3]

13 9700/22/M/J/16 © UCLES 2016 [Turn over (b) State two differences between the chromosome at metaphase and the chromosome at late anaphase. … … … … … …[2] (c) One of the functions of a plant hormone known as cytokinin is to act as a cell signalling molecule and promote cytokinesis. Suggest how cytokinin acts as a cell signalling molecule. … … … … … … … …[3] [Total: 9]

14 9700/22/M/J/16 © UCLES 2016 6 One of the enzymes involved in glycogen synthesis is glycogen synthase. The monomer of the glycogen polymer is α-glucose. (a) (i) Draw the ring form of α-glucose in the space provided. [2] (ii) Glycogen synthase catalyses the formation of a covalent bond between two α-glucose molecules during glycogen synthesis. Name the type of bond formed. …[1] (iii) Glycogen branching enzyme is another enzyme that is required for glycogen synthesis. Suggest why glycogen branching enzyme is needed in addition to glycogen synthase. … … … …[1] (b) The gene coding for glycogen synthase in muscle cells is known as GYS1. (i) Explain what is meant by a gene. … … … … …[2]

15 9700/22/M/J/16 © UCLES 2016 (ii) There are a number of known mutations for GYS1. Outline how a mutation in GYS1 can lead to the formation of an altered polypeptide where one amino acid is replaced by a different amino acid. … … … … … … … …[3] (c) Table 6.1 shows three functions of cell structures that are involved in the synthesis of glycogen synthase. Complete Table 6.1 by naming the cell structure that carries out the function listed. Table 6.1 function name of cell structure assembles ribosomes for polypeptide synthesis synthesises ATP to provide a supply of energy for transcription of GYS1 folds and modifies synthesised polypeptide to produce functioning glycogen synthase [3] [Total: 12]

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® IGCSE is the registered trademark of Cambridge International Examinations. This document consists of 10 printed pages. © UCLES 2016 [Turn over Cambridge International Examinations Cambridge International Advanced Subsidiary and Advanced Level BIOLOGY 9700/22 Paper 2 AS Level Structured Questions May/June 2016 MARK SCHEME Maximum Mark: 60 Published This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the details of the discussions that took place at an Examiners’ meeting before marking began, which would have considered the acceptability of alternative answers. Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for Teachers. Cambridge will not enter into discussions about these mark schemes. Cambridge is publishing the mark schemes for the May/June 2016 series for most Cambridge IGCSE®, Cambridge International A and AS Level components and some Cambridge O Level components.

Page 2 Mark Scheme Syllabus Paper Cambridge International AS/A Level – May/June 2016 9700 22 © Cambridge International Examinations 2016 Mark scheme abbreviations ; separates marking points / alternative answers for the same point R reject A accept (for answers correctly cued by the question, or by extra guidance) R reject A accept (for answers correctly cued by the question, or by extra guidance AW alternative wording (where responses vary more than usual) underline actual word given must be used by candidate (grammatical variants accepted) max indicates the maximum number of marks that can be given ora or reverse argument mp marking point (with relevant number) ecf error carried forward I ignore AVP alternative valid point

Page 3 Mark Scheme Syllabus Paper Cambridge International AS/A Level – May/June 2016 9700 22 © Cambridge International Examinations 2016 1 (a) A activation energy / energy of activation ; B induced fit ; A induced fit, model / hypothesis / theory / mechanism C globular ; D extracellular ; E Michaelis-Menten constant ; A Km [5] [Total: 5] 2 (a) (i) curled / rolled, leaf ; R curly / curved / folded or trichomes / hairs ; A hair / hairy,-like structures R cilia / spines / needles [1] (ii) allow explanations for stomata in pits, thick cuticle and no stomata on outer surface as ecf from (i) curled leaf / trichomes / stomata in pits ref. to (creates) still / non-moving, air ; (in enclosed area) humid / moist ; AW, e.g. traps water vapour / maintains humidity water potential gradient less steep or decreased rate of diffusion of water vapour (out) ; A (water) vapour pressure gradient for water potential gradient I decreased concentration gradient of water vapour assume in context of between substomatal air space and enclosed area unless stated otherwise thick cuticle greater layer impermeable wax / AW ; A thicker waterproof layer increases distance for diffusion ; of water vapour ; no stomata on outer surface most water lost via (open) stomata ; cuticular transpiration only ; ref. to where most exposure to, light / air currents / wind ; [max 2] (b) xerophytic / xerophyte ; [1] [Total: 4]

Page 4 Mark Scheme Syllabus Paper Cambridge International AS/A Level – May/June 2016 9700 22 © Cambridge International Examinations 2016 3 (a) (i) 1179 ;; one mark if not to the whole person e.g. 1179.24 / 1179.2 or if calculation correct but answer incorrect e.g. 1.39 × 848.38 or 1.39 × (84 838 000/100 000) or if no calculation to check but answer given as 1180 [2] (ii) 1 provides information about / AW, proportion / percentage, (of population) affected / AW ; 2 to, make (valid) comparisons / compare ; between countries / in one country over time 3 provides information about severity of disease ; AW 4 population size, taken into account / different for different countries / changes over time in a country ; do not need ‘size’ if ‘use of ‘population’ is in correct context 5 idea that countries with larger populations will usually have more cases / higher number of cases may just mean larger population of country; 6 AVP ; gives guidance about whether the disease is, spreading / becoming an epidemic / dying out (in one country) in context of over time idea that number of cases per 100 000 are, standardised / normalised, values 7 use of data to support ; only two of Chad, Eritrea or Ethiopia where comparisons between countries stated I ref. to other countries (2009) actual cases and standardised cases comparison (2009) to support mp 5 population size and actual cases stated values of similar number of cases per 100 000 and populations of different sizes countries compared, number of cases per 100 000 for any stated year, with comment about severity number of cases per 100 000 for one country over time, with comment about severity / spreading / dying out / control / AW [max 3]

Page 5 Mark Scheme Syllabus Paper Cambridge International AS/A Level – May/June 2016 9700 22 © Cambridge International Examinations 2016 (b) can give values of percentage vaccinated to describe ‘increasing / decreasing’ percentage vaccination support 1 Gambia high percentage vaccinated (throughout) and low number of cases ; A Eritrea 2 data to support ; e.g. a percentage vaccination for a year and number of cases (same, or following, year after vaccination) or a range given for percentage vaccinations over the whole, or stated, number of years or a compilation of the two partial / weak, support 3 Central African Republic decreasing vaccination and number of cases in 2011, higher / 15.31 ; 4 Chad (from 2008) increasing percentage vaccination and, low / stated, number of cases, 2009 / 2010 / 2012 ; 1.45 1.66 0.96 do not support 5 Niger / Ethiopia / Chad, (generally) increasing percentage vaccinated and number of cases, fluctuates / increase and decrease (ora) / AW ; A stated correct data to show increase and decrease A for Chad if mp 4 given and ref. to increase / 71.6 in 2011 6 (generally) increasing percentage vaccinated and number of cases, increases / goes from 2.34–4.67, in 2011 in Niger or increases / goes from 1.39–4.86, in 2010 in Ethiopia or increases / goes from 1.66–71.6, in 2011 in Chad A 1.45–1.66 in 2010 ; 7 Central African Republic decreasing vaccination and low number of cases in, 2009 / 2010 / 2012 ; 8 / 9 AVP ;; e.g. • idea that most values for number of cases are low irrespective of vaccination percentage • ref.to needs, high / 90%, vaccination to be effective A < 80% / low, vaccination ineffective • idea that generally Gambia / Eritrea, have higher percentage vaccinated and have lower number of cases than, (three of) Ethiopia, Chad, Central African Republic, Niger / the other countries • ref. to Chad / Central African Republic, in 2011 and, epidemics / inability to keep number of cases down / ineffectiveness of vaccination programme I ref. to 71.6 (Chad) or 15.31 (Central African Republic) • Eritrea 2012 high vaccination but, increase in / 3.16, cases • ref. to increasing percentage of vaccination in Niger and decrease in cases, 2009–2010 from 5.23 to 2.34 / 2011–2012 from 4.67–1.59 A 2009–2012 from 5.23 to1.59 [max 4]

Page 6 Mark Scheme Syllabus Paper Cambridge International AS/A Level – May/June 2016 9700 22 © Cambridge International Examinations 2016 (c) points refer to smallpox, look for points written as ora any two from 1 high, percentage / proportion, immunised / vaccinated ; AW A mass vaccination 2 no boosters required / one dose enough / immunity very long-lived ; A idea of long-lasting effect of vaccine 3 same, vaccine / antigens, used (throughout) ; treat as neutral ref. to, low mutation rate / stability, of smallpox virus 4 heat stable / thermostable / freeze-dried / lyophilised, vaccine ; I frozen A no need to refrigerate / AW A idea of longer shelf-life 5 ease of, administering vaccine / training people to give vaccine ; 6 ring vaccination / described, e.g. contact tracing ; 7 easy to identify infected people / AW, (to begin ring vaccination) ; 8 lower percentage cover required for smallpox than measles / lower herd immunity required ; 9 AVP ; smallpox less infectious (so lower percentage cover required) idea of less, civil unrest / war / movement of populations (so easier to implement) suggestion that smallpox live vaccine (and measles not live) [max 2] (d) active artificial / artificial active ; treat as neutral acquired [1] (e) can be from point of view of country programme or WHO programme cost 1 preparing / manufacturing / purchasing, vaccine ; A cost to provide vaccine free to developing countries 2 disposables / equipment to administer (vaccine) ; e.g. syringes / needles / (protective) gloves 3 storage ; e.g. space, security 4 refrigeration / maintaining cold chain ; 5 transport (of, vaccine / health care workers) ; 6 wages / training, of staff involved ; e.g. wages for, health care workers administering vaccine / staff involved in training health care workers 7 record keeping / contact tracing ; 8 advertising / informing / marketing / education ; 9 research / development ; 10 setting up vaccination / immunisation, camps (for remote / epidemic, areas) ; I building, hospitals / clinics [max 2] [Total: 14]

Page 7 Mark Scheme Syllabus Paper Cambridge International AS/A Level – May/June 2016 9700 22 © Cambridge International Examinations 2016 4 (a) blood contained in (blood) vessels AW or blood contained in any three of heart, arteries, veins, capillaries ; systemic and pulmonary, systems / circulation ; A ‘systematic’ A described if circulations not named e.g. for each complete circuit (round the body) passes through heart twice from heart to lungs and back, then to (rest of) body and back [2] (b) W = aorta / aortic arch ; X = pulmonary vein ; Y = right atrioventricular / tricuspid, (valve) ; Z = left, atrium / auricle ; [4] (c) red blood cells ; A rbc A platelets A plasma proteins / named [1] (d) 1 idea of carbon dioxide out (of blood to alveolus) and oxygen in (to alveolus from blood) ; 2 diffusion / diffuses or (movement from) high concentration to low concentration / down a concentration gradient ; A diffusion / pressure, gradient 3 (across) squamous epithelium / squamous cells (of alveolar wall) ; A pavement cells 4 (and) endothelium / endothelial cells (of capillary wall) ; A squamous cells but must be clear that this is for capillary wall 5 oxygen, into / AW, red blood cells ; I oxygen binds to Hb 6 steep gradient maintained by, ventilation / uptake by haemoglobin / blood carries oxygen away / blood arrives with carbon dioxide / deoxygenated blood arriving low in oxygen [max 4] (e) (i) F = nucleolus ; A nucleus G = cell surface / plasma, membrane ; [2]

Page 8 Mark Scheme Syllabus Paper Cambridge International AS/A Level – May/June 2016 9700 22 © Cambridge International Examinations 2016 (ii) transport / transporter / carrier, protein ; R pump protein specific protein ; glucose, binding site / AW ; I glucose binds R glucose receptor specific binding site (in protein) = 2 marks (glucose binding causes) conformational change ; AW, e.g. changes shape passive / no energy required / no ATP required ; movement is, down the concentration gradient / from high to low concentration ; must be in context of through the membrane protein [max 3] [Total: 16] 5 (a) (i) coiling / supercoiling / condenses / condensation ; A become shorter and thicker R contracts [1] (ii) accept from labelled diagram two chromatids ; identical / sister, chromatids ; joined by a centromere ; A kinetochore one from (reach chromatid) DNA complexed with protein histone proteins / histones ; telomeres at end of chromatids [max 3] (b) metaphase versus anaphase idea of single chromosome of two chromatids versus two separated chromatids / daughter chromosomes e.g. two chromatids versus, one chromatid / one daughter chromosome ; sister chromatids joined at centromere versus chromatids separated distance between sister chromatids zero versus increasing distance between chromatids share a centromere versus do not share a centromere / centromere divides two DNA molecules versus one DNA molecule ; at, equator / metaphase plate versus towards / at, poles ; R centre R ends linear / straight versus V shape / AW ; [max 2]

Page 9 Mark Scheme Syllabus Paper Cambridge International AS/A Level – May/June 2016 9700 22 © Cambridge International Examinations 2016 (c) acts at target cell ; binds to receptor ; R receptor cells allow ecf for other mps R trapped / caught ref. specificity ; A receptor complementary (shape) for cytokinin A cytokinin fits into receptor this is also mp2 A recognition of cytokinin by receptor receptor (located) in, cell surface / plasma, membrane ; A cell membrane A phospholipid bilayer A transmembrane receptor sets off / AW, response in the cell / described response(s) ; e.g. triggers secondary messenger activates enzyme(s) I signals / causes / stimulates, cell to divide / cytokinesis (acts) extracellularly / extracellular signal or (acts) intracellularly / intracellular signal ; must be in context of candidate’s answer [max 3] [Total: 9] 6 (a) (i) two marks for correct drawing of ring structure ;; all atoms shown or one of diagrams 1–3 above one mark if, inconsistent / incomplete, drawing: diagram 1 – one missing H from any of carbons 2–6 (OH groups and rest of drawing must be correct) diagrams 2 and 3 – adding the H to one of carbons 1–5 (OH groups and rest of drawing must be correct) [2] (ii) glycosidic ; A glucosidic [1] (iii) to form / has, (glycosidic α) 1–6, bonds / links (to make branches) ; ref. to different shaped / specific / complementary, active site required to form bonds (for branching) ; [max 1] 1 2 3 H H H H H OH O O O OH OH OH OH OH OH OH OH OH HO HO OH CH2OH CH2OH

Page 10 Mark Scheme Syllabus Paper Cambridge International AS/A Level – May/June 2016 9700 22 © Cambridge International Examinations 2016 (b) (i) treat as neutral unit of inheritance sequence of, nucleotides / bases ; section / length / part, of DNA (molecule) ; codes for a polypeptide ; A protein for polypeptide A enzyme A information to produce a polypeptide A codes / information, for sequence of amino acids / primary structure (of a, polypeptide / protein) R genetic code for a polypeptide [max 2] (ii) 1 (in DNA / gene) altered, sequence / AW, of, nucleotides / bases ; I DNA sequence 2 base substitution or base / nucleotide, replaces another, base / nucleotide; A example must be in context of, DNA / gene 3 (mRNA synthesised) during transcription ; 4 (mutation leads to) altered / AW, mRNA / messenger RNA ; 5 (only) one (mRNA) codon changed / a different codon ; A one DNA, triplet / codon, changed I ref. to codons changed 6 tRNA, with / has, a different anticodon ; 7 (tRNA) brings, a different / a changed / the incorrect, amino acid, during translation / to the ribosome ; 8 codon-anticodon, binding / complementary / AW ; A matches R amino acid with anticodon [max 3] (c) nucleolus ; R if other cell structures given mitochondrion ; R if other cell structures given rough endoplasmic reticulum or Golgi (body / apparatus / complex) ; [3] [Total: 12]