UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS GCE Advanced Subsidiary Level and GCE Advanced Level MARK SCHEME for the October/November 2010 question paper for the guidance of teachers 9700 BIOLOGY 9700/11 Paper 1 (Multiple Choice), maximum raw mark 40 Mark schemes must be read in conjunction with the question papers and the report on the examination. • CIE will not enter into discussions or correspondence in connection with these mark schemes. CIE is publishing the mark schemes for the October/November 2010 question papers for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses. www.maxpapers.com
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UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS
GCE Advanced Subsidiary Level and GCE Advanced Level
MARK SCHEME for the October/November 2010 question paper
for the guidance of teachers
9700 BIOLOGY
9700/11 Paper 1 (Multiple Choice), maximum raw mark 40
Mark schemes must be read in conjunction with the question papers and the report on the examination.
• CIE will not enter into discussions or correspondence in connection with these mark schemes. CIE is publishing the mark schemes for the October/November 2010 question papers for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses.
www.maxpapers.com
Page 2 Mark Scheme: Teachers’ version Syllabus Paper
UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS
GCE Advanced Subsidiary Level and GCE Advanced Level
MARK SCHEME for the October/November 2010 question paper
for the guidance of teachers
9700 BIOLOGY
9700/12 Paper 1 (Multiple Choice), maximum raw mark 40
Mark schemes must be read in conjunction with the question papers and the report on the examination.
• CIE will not enter into discussions or correspondence in connection with these mark schemes. CIE is publishing the mark schemes for the October/November 2010 question papers for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses.
www.maxpapers.com
Page 2 Mark Scheme: Teachers’ version Syllabus Paper
UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS
GCE Advanced Subsidiary Level and GCE Advanced Level
MARK SCHEME for the October/November 2010 question paper
for the guidance of teachers
9700 BIOLOGY
9700/13 Paper 1 (Multiple Choice), maximum raw mark 40
Mark schemes must be read in conjunction with the question papers and the report on the examination.
• CIE will not enter into discussions or correspondence in connection with these mark schemes. CIE is publishing the mark schemes for the October/November 2010 question papers for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses.
www.maxpapers.com
Page 2 Mark Scheme: Teachers’ version Syllabus Paper
UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS
GCE Advanced Subsidiary Level and GCE Advanced Level
MARK SCHEME for the October/November 2010 question paper
for the guidance of teachers
9700 BIOLOGY
9700/21 Paper 2 (AS Structured Questions), maximum raw mark 60
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 must be read in conjunction with the question papers and the report on the examination.
• CIE will not enter into discussions or correspondence in connection with these mark schemes. CIE is publishing the mark schemes for the October/November 2010 question papers for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses.
www.maxpapers.com
Page 2 Mark Scheme: Teachers’ version Syllabus Paper
Mark Scheme abbreviations: ; separates marking points / alternative answers for the same point R reject A accept (for answers correctly cued by the question or guidance on the mark scheme) AW alternative wording (where responses may vary more than usual) underline actual word given must be used by the candidate (grammatical variants excepted) max indicates the maximum number of marks that can be given ora or reverse argument
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Page 3 Mark Scheme: Teachers’ version Syllabus Paper
1 (a) community ; niche ; A role second trophic level / first level consumers / primary consumer level ; A other appropriate terms [3] (b) loss (of energy-containing food in producers or in grazers) in indigestible parts / not being absorbed / faeces / egestion ;; one mark for producer, one mark for grazer excretion (in, grazers / herbivores / primary consumers) ; respiration (in, grazers / herbivores / primary consumers) ; loss of energy in movement / AW (in, grazers / herbivores / primary consumers); AVP ; e.g. heat energy [max 2] [Total: 5] 2 (a)
structure trachea bronchus bronchiole alveolus
ciliated epithelium � � � �
goblet cells � � � / � �
cartilage � � � �
smooth muscle � � � �
one mark each row [4] (b) (i) athlete takes a deep breath and then breathes out as much air as possible / AW ; suitable method to record this, e.g. spirometer / breathing out into a bell jar of water ; [2] (ii) 0.5 dm3 / 500 cm3 ; [1] (c) reduced supply of blood to, heart / cardiac, muscle ; reduced supply of glucose (to cardiac muscle) ; R no reduced supply of oxygen (to cardiac muscle) ; R no less aerobic respiration / (more) anaerobic respiration (of cardiac muscle) ; build up of, lactate / carbon dioxide ; ref. limited cardiac output ; AVP ; e.g. ref. to consequences to (muscles of) body with reduced blood supply, ref. to
pain caused by angina R heart attack / AW [3]
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Page 4 Mark Scheme: Teachers’ version Syllabus Paper
(d) damages, lining of arteries / endothelium ; accept once speeds up (atheromatous / fibrous) plaque development ; accept once increases chance of blood clotting / promotes thrombosis ; accept once nicotine increases heart rate / AW ; increases blood pressure ; makes platelets ‘sticky’ ; decreases blood flow to, extremities / AW ; constriction of blood vessels ; (max 2) carbon monoxide combines with haemoglobin / forms carboxyhaemoglobin / higher affinity for
haemoglobin (than oxygen) ; reduces oxygen-carrying capacity / AW (in context of, haemoglobin / blood) ; promotes release of damaging free radicals / peroxides / superoxides / oxidising agents ; causes, platelets and neutrophils to stick together / platelets to stick to endothelium ; ref. hypoxia damage to cardiovascular system ; (max 2) [max 3] [Total: 13] 3 (a) accept ora penalise once if refs. in context of rates e.g. faster no cells remaining, correct concentration value given (accept up to 0.26%) ; 100% / AW, cells remaining, ref. from 0.86%–0.9% / AW ; steep increase in percentage cells remaining between 0.5–0.8% ; A to 0.7% if next
marking point included steepest increase between 0.7–0.8% ; comparative data quote to support ref. to increase ; [max 3] (b) max 5 if no mention of water potential anywhere in the answer correct use of term osmosis linked to water potential (in context of high to low) ; 0% and 0.7% (net) water in (to red cells) ; 0%, all cells burst / (haemo)lysis of all cells ; general ref. to bursting at 0.7%, some cells burst ; ora either concentration ; cell membrane cannot withstand pressure ; (0.7%) (remaining) cells swollen / cell volume increases ; 0.7% water potential gradient not as steep as in, water / 0% ; 1.5% (net) loss of water from cells ; cells, shrink / AW or cell volume decreases ; A descriptions relative to biconcave disc shape [max 6]
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Page 5 Mark Scheme: Teachers’ version Syllabus Paper
(c) 4, oxygen molecules / O2, per (molecule of) haemoglobin ; (forms) oxyhaemoglobin (in lungs) ; A marking points 1 and 2 as equation ref. oxygen remains bound until blood in area of low pO2 / high pCO2 / high(er)
temperature ; A in area of respiring tissues (max 3) carbon dioxide combines with haemoglobin ; terminal, amine / amino, group of haemoglobin ; A –NH2 carbamino-haemoglobin ; R carboxyhaemoglobin ref. to hydrogen ions from carbonic acid ; ref. carbon dioxide remains bound until blood in area of low pCO2 / high pO2 ; [max 4] (d) (i) 19.7 / 20 (%) ;; allow 1 mark if incorrect answer but correct working shown 7.3 – 6.1 / 6.1 × 100 / 1.2 / 6.1 × 100 [2] (ii) partial pressure / AW, of oxygen is, low / lower than at sea level ; haemoglobin less well saturated ; more red blood cells / more haemoglobin ; compensates for, smaller volume of oxygen absorbed (per red blood cell) / lower
saturation of haemoglobin ; A ref. to tissues receiving sufficient oxygen AVP ; e.g. ref to erythropoietin (EPO) [max 3] [Total: 18] 4 (a) (i) Vibrio cholerae ; [1] (ii) active transport / described as movement against concentration gradient ; A facilitated diffusion / described [1] (iii) (bacteria) leave infected person in faeces / AW ; (bacteria) enter water supply / AW ; A idea of contaminated, food / utensils (bacteria) ingested by uninfected person ; [3] (b) must be in context of B-lymphocytes / B-cells / plasma cells max 3 if T-cells secondary response A ora presence of memory cells / AW (giving larger numbers) ; ref. increased chance of, encountering antigen / antigen presentation / clonal selection ; ref. larger numbers cells following, clonal expansion / AW (cf primary response) ; (so) shorter duration for onset of antibody production ; (so) higher antibody concentration ; secondary response antibody production (by plasma cells) lasts longer ; AVP ; e.g. faster rate, plasma cell / antibody, production, ref. longer-life of cells
involved in secondary response [max 4]
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Page 6 Mark Scheme: Teachers’ version Syllabus Paper
(c) 1 poor sanitation / no treatment of faecal waste / AW ; 2 contamination of (drinking) water supply ; 3 poverty, qualified / poor living conditions 4 poor hygiene ; 5 poor / lack of, (health) education about transmission ; 6 ref to natural disasters ; e.g. assistance / aid / medical help / AW, cannot arrive in
time 7 ref. refugees / displaced people ; 8 lack of, water purification equipment / bottled water / AW ; 9 no rehydration therapy available (at time when needed) ; 10 no (effective) vaccine ; 11 further detail ; (bacteria live in gut, where immune system is not effective) 12 AVP ; e.g. contamination of vegetable plots with faecal waste, ref. to different
strains [max 4] [Total: 13]
5 (a) (i) β glucose ; [1] (ii) glycosidic ; [1] (b) many hydrogen bonds within the molecule ; idea of parallel chains / AW ; hydrogen bonds between cellulose molecules ; to form microfibrils ; held together by more hydrogen bonds to form fibres ; [2 max] (c)
function letter from Fig. 5.1
organelle that contains DNA H
structure that transports cell wall material to the cell surface membrane A
site of transcription H
site of ribosome synthesis J
site of photosynthesis D
[4] (d) polypeptide / protein, in (cisternae of) RER ; to Golgi (apparatus / AW) ; modification / glycosylation / packaging ; vesicle(s) formed / transport in vesicle ; A vacuole membrane of vesicle fuses with cell surface membrane ; exocytosis / described ; [max 3] [Total: 11]
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UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS
GCE Advanced Subsidiary Level and GCE Advanced Level
MARK SCHEME for the October/November 2010 question paper
for the guidance of teachers
9700 BIOLOGY
9700/22 Paper 2 (AS Structured Questions), maximum raw mark 60
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 must be read in conjunction with the question papers and the report on the examination.
• CIE will not enter into discussions or correspondence in connection with these mark schemes. CIE is publishing the mark schemes for the October/November 2010 question papers for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses.
www.maxpapers.com
Page 2 Mark Scheme: Teachers’ version Syllabus Paper
Mark Scheme abbreviations: ; separates marking points / alternative answers for the same point R reject A accept (for answers correctly cued by the question or guidance on the mark scheme AW alternative wording (where responses may vary more than usual) underline actual word given must be used by the candidate (grammatical variants excepted) max indicates the maximum number of marks that can be given ora or reverse argument
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Page 3 Mark Scheme: Teachers’ version Syllabus Paper
1 (a) (i) transcription first process and exocytosis final process ; correct order for remaining three processes (3, 4, 2) ; [2] accept words and mixture of words and letters (ii) F ; A / D A ; C D ;
events order of events
cell location (letter)
exocytosis 5 F cell membrane ;
protein modification 3 A / D A+D
Golgi and/or RER ,
secretory vesicle formation 4 A Golgi ;
transcription 1 C nucleus ,
translation 2 D RER ;
[3] (b) 1 vesicle / vacuole, moves towards, cell, surface / membrane ; A plasma membrane R if lysosome 2 fusion / described, of vesicle with membrane ; R attach / bind / combine 3 ref. to (fluid nature of) phospholipids ; 4 contents / AW, secreted / released / exported / removed / emptied / excreted ; A waste material / digested material 5 active process / energy-requiring / ATP used / AW ; R ‘active transport’ R endocytosis [max 3] (c) (i) AUG ; [1]
(ii) 1 secondary structure / α-helix / β-(pleated) sheet ; 2 tertiary structure / description / folding / complex 3D shape ; 3 formation of named bond(s) ; R if peptide bond in list 4 quaternary structure / description (e.g. assembly of polypeptides) ; 5 glycosylation / formation of glycoproteins / addition of carbohydrate(s) or sugar(s) ;
R hydrocarbon chain 6 addition of, non-protein portion(s) / prosthetic group(s) / named example ; A haem / iron / Fe / copper / Cu / magnesium / Mg / AW 7 removal of some amino acids ; R one amino acid 8 polypeptide(s) cut into two or more pieces ; 9 AVP ; e.g. ref. to exposure to water molecules and folding R ref. to amino acids coded for by stop codons [max 2] [Total: 11]
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Page 4 Mark Scheme: Teachers’ version Syllabus Paper
2 (a) communicable / transmissible / contagious / transferable / AW ; A passed from one (infected), host / organism / one person, to another A ‘passed on’ caused by, a pathogen / microorganism / at least two named types of pathogen ; A virus, bacterium, fungus, protoctist, worm ; R parasite unqualified by two types [max 2] (b) Plasmodium, falciparum / ovale / vivax / malariae ; A phonetic spellings for specific name, A plasmodium R if specific name first, [1] (c) (i) (only) female feeds on blood / male does not feed on blood ; female requires blood (protein) for (development of) eggs ; (only) female carries, pathogen / disease-causing organism / Plasmodium / parasite ; A (only) female transmits the disease (only) female is vector ; ora ignore female carries, the disease / malaria [max 1] (ii) anti-coagulant (in saliva) is passed when mosquito, sucks blood / feeds / bites / takes a
a blood meal ; [max 1] (iii) in marking accept Plasmodium / pathogen / causative organism / malarial organism where parasite is given
below short time (in blood plasma) for exposure to cells of the immune system / AW ; next stage(s) of life cycle inside cells ; A sporozoites into merozoites in liver / merozoites into schizonts in red blood cells parasite gains, food / energy, from cells ; parasite, reproduces / multiplies, inside (liver / red blood) cells ; damage to / bursting of / lysis of / impaired function of, cells ; (antimalarial) drugs cannot penetrate (liver / red blood) cells ; parasite, concealed / ‘hides’, from host immune system ; A antigen concealment ; no symptoms, until parasite leaves cells / while parasite is in cells ; idea that people incubating disease are symptomless ; A symptomless carriers idea that treatment unlikely to prevent spread from infected person ; AVP ; examples different stages provide problems with drug / vaccine development AVP ; mode of action of potential drugs – block attachment sites on cells parasite in blood cells allows testing by taking blood samples further development of any idea given above [max 2]
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Page 5 Mark Scheme: Teachers’ version Syllabus Paper
(d) if virus / bacterium / disease used instead mark to max 3 in marking accept Plasmodium / pathogen / causative organism / malarial organism where parasite is given
below distribution described for one mark either (mainly in) tropics / between the tropics or any two named, areas and/or countries, affected ; e.g. areas (sub-Saharan) Africa, Central America, South America, South Asia, Central
Asia, Middle East, Caribbean e.g. countries India, Sri Lanka, China, Vietnam, Cambodia, Brazil, Kenya discussion to max four 1 (areas where) both parasite, and, vector / mosquito / Anopheles, are present ; 2 Anopheles / mosquito / vector, survives / breeds / lives, in, hot and humid areas / moist
tropical areas ; ora A standing / stagnant, water 3 parasite, needs to reproduce within the mosquito (at temperatures above 20°C) ; 4 eradicated in some countries / any e.g. (USA, Italy) ; 5 ref to LEDCs and, poor / non-existent, control programmes ; A poor health facilities / poor drug supplies / AW 6 mosquitoes resistant to, DDT / insecticides / pesticides ; 7 parasite resistant to, chloroquine / drugs ; 8 link between human population density and Anopheles ; e.g. human activity provides (lots of) breeding sites for Anopheles 9 occurs where named high risk group(s) exist ; e.g. refugees, HIV-positive pregnant women (more likely to pass HIV to unborn
children), (young) children 10 (outside tropics) disease spread by, travellers / tourists / migrants / refugees ; 11 AVP ; most cases / over 90% cases, in (sub-Saharan) Africa not, at high altitude / in deserts different species of Plasmodium differ in geographical distribution / AW misdiagnosis (so not reported) changing pattern linked to, global warming / changes in land use / deforestation /
irrigation / other relevant named R references to sickle cell [max 4] [Total: 11]
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Page 6 Mark Scheme: Teachers’ version Syllabus Paper
3 (a) spherical / ball-shaped / AW ; A round(ed) / circular has tertiary structure ; R 3D hydrophilic / polar, (R) group(s), on outside / face to watery exterior ; hydrophobic / non-polar, (R) group(s), in centre ; water soluble ; [max 3] (b) (i) idea that plant cell walls and fungal cell walls have different components fungal cell walls made of, glucans / chitins / fungal cellulose / different components to
plant cell walls ; A peptidoglycan / murein A plant cell walls contain cellulose, but fungi do not idea of specificity in context of question enzymes are specific ; A specificity explained e.g. both substrates not complementary / shape of active site
specific to one substrate [2] (ii) 1 (at optimum pH) maximum / peak, activity ; A most efficient / works best 2 above / below, optimum, activity declines ; A description / graph sketched with pH and rate / activity 3 changing pH changes hydrogen ion concentration ; 4 hydrogen / ionic, bonds (between amino acids), break / disrupted ; 5 hydrogen / ionic, bonds, important in maintaining shape of, tertiary structure / active
site ; R 4 and 5 if refer to disulfide, hydrophobic interactions, peptide at sub-optimum pH 6 active site / tertiary, shape altered ; A enzyme denatured 7 charges at the active site may be affected ; 8 further detail ; e.g. transfer of electrons may not be possible 9 the substrate may be altered by pH changes ; R cell wall unqualified 10 (therefore) substrate no longer fits / ES complexes not formed ; [max 3] (c) osmosis, defined in terms of water potential / used in correct context ; 0% and / or 0.4% higher / less negative, water potential outside so water enters ; 0%, higher / less negative, water potential than 0.4%, so cells burst ; ora 0.9% equal / same, water potential inside and outside cells, water in = water out ; A no net movement of water / ref. to isotonic / no water potential gradient R ‘no osmosis’ / no movement of water 1.5% and / or 3.0% lower / more negative, water potential outside so water moves out ; 3.0%, lower / more negative, water potential than 1.5% so cells, smaller / AW ; [max 4] (d) cells, increase in size / burst ; A vacuole increases in size R becomes turgid no cell wall to, prevent cell bursting / withstand (turgor) pressure ; A idea that cell membrane alone cannot withstand increase in size / bursting [2] [Total: 14]
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Page 7 Mark Scheme: Teachers’ version Syllabus Paper
plasma cells and Th-lymphocytes ; [3] no ecf from (a) to (b) (b) 1 active (artificial) immunity ; 2 memory cells / immunological memory ; 3 idea that many specific, B-cells / T-cells / lymphocytes, in the body ; A large(r) clones of specific, B- / T-cells or lymphocytes actual invasion by the pathogen 4 fast secondary (immune) response ; 5 fast increase in antibodies / immediate production of antibodies ; ignore incorrect type of cell secreting antibodies 6 high(er) concentration of antibodies are produced ; A more antibodies produced 7 pathogen destroyed before person becomes ill / AW ; R antigen A pathogen do not, increase in number / infect cells / AW [max 3] (c) two points to look for (if) most / sufficient / many / AW, people / children, immunised / vaccinated ; A herd immunity reduces the pool of infected, people / children, in the, community / population ; A fewer people can catch disease and be source of infection A protects those unvaccinated as, disease / illness, does not spread A less chance of transmission A pathogen cannot develop in immunised people A reduced exposure to pathogen [max 2] [Total: 8]
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Page 8 Mark Scheme: Teachers’ version Syllabus Paper
5 (a) glycogen ; [1] (b) xerophyte / xerophyllic ; A phonetic e.g. zerophyte [1] (c) haploid (cell) ; A monoploid [1] (d) (primary) producer ; R first ignore autotrophic [1] (e) (nitrogen) fixation ; A nitrogen fixing bacteria [1] [Total: 5] 6 (a) (i) squamous / pavement (epithelial) ; [1] (ii) stretch / expand, on inspiration and recoil on expiration ; R contraction (stretch) to increases, surface area / volume of air, for, diffusion / gas exchange ; (recoil) to help, expel air / force air out ; A carbon dioxide A if destroyed then cannot expel air prevent alveoli, bursting / breaking / AW ; ref. to emphysema if elastic fibres destroyed ; [max 2] (b) award two marks if correct answer (anything in range 336–346) allow +/– 1 mm in reading the line (74–76 mm)
75000 µm / 220 µm = 341 ;; if answer incorrect, award one mark for correct measurement with unit and division by 220 award one mark if correct answer given to one or more decimal places [2] (c) look for two ideas – follow usual rules for marking numbered answer lines thin, alveolar wall / epithelial lining / AW ; A short diffusion distance (between air in alveolus and blood in capillary) A squamous cells are thin R thin, membrane / cell membrane R large surface area surrounded by, capillaries / capillary network ; A close contact with, capillaries / blood (vessels / cells) A many capillaries A large area of alveolus in contact with, capillaries / blood [2]
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Page 9 Mark Scheme: Teachers’ version Syllabus Paper
(d) max 3 if no ref. to diffusion (named) gas(es), diffuse down, pressure gradients / concentration gradient / AW ; A from high(er) partial pressure to low(er) partial pressure A high(er) concentration to low(er) concentration ignore ‘along a concentration gradient’ in the answers accept the following AWs capillaries / haemoglobin for blood lungs for alveoli body for tissues lungs valid statement linking information in table below – 1 mark for each row comparison in partial pressure may be ‘higher / lower’ not both or high and low, but if not
then figures have to be given
blood ref. to gas
blood partial pressure
alveolar air partial pressure
gas exchange
pO2 5.33 / lower 13.87 / higher into blood from alveolus
;
in pulmonary artery / entering alveolar capillaries
pCO2 6.00 / higher 5.33 / lower out of blood into alveolus
;
respiring tissue valid statement linking information in table below – 1 mark for each row
blood ref. to gas
blood partial pressure
tissue partial pressure
gas exchange
pO2 13.33 / higher < 5.33 / lower into tissue from blood
;
in systemic artery / entering tissue capillaries
pCO2 5.33 / lower > 6.00 / higher out of tissue into blood
;
[max 4] R differences between pO2 and pCO2 in the same place [Total: 11]
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UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS
GCE Advanced Subsidiary Level and GCE Advanced Level
MARK SCHEME for the October/November 2010 question paper
for the guidance of teachers
9700 BIOLOGY
9700/23 Paper 2 (AS Structured Questions), maximum raw mark 60
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 must be read in conjunction with the question papers and the report on the examination.
• CIE will not enter into discussions or correspondence in connection with these mark schemes. CIE is publishing the mark schemes for the October/November 2010 question papers for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses.
www.maxpapers.com
Page 2 Mark Scheme: Teachers’ version Syllabus Paper
Mark Scheme abbreviations: ; separates marking points / alternative answers for the same point R reject A accept (for answers correctly cued by the question or guidance on the mark scheme) AW alternative wording (where responses may vary more than usual) underline actual word given must be used by the candidate (grammatical variants excepted) max indicates the maximum number of marks that can be given ora or reverse argument
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Page 3 Mark Scheme: Teachers’ version Syllabus Paper
1 (a) (i) A phospholipid ; (1) B protein ; ignore protein descriptions R glycoprotein R lipoprotein (1) [2] (ii) polar / hydrophilic, head / group ;
attracted to / AW, water / aqueous environment ; A water-loving ref. hydrogen bonding (polar head to water) ; non-polar / hydrophobic / hydrocarbon / fatty acid, tails / chains / groups ; repelled by / away from, water / aqueous environment ; AW R water-hating [max 3]
(b) C any one of
(channel) allows, ions / water / polar molecules / water-soluble molecules / hydrophilic molecules, to, pass through membrane / enter cell / leave cell ; R transport, without qualification e.g. across, through facilitated diffusion ; active transport ; (max 1)
D any one relevant e.g.
cellular recognition cell identification antigen cell signalling receptor binding site ref to hydrogen bonding with water / forms bond with water to stabilise membrane cell adhesion (max 1) [2]
(c) 1764 ;; if correct working (588 × 3) is shown, but no answer or incorrect answer, award one
mark [2] [Total: 9]
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Page 4 Mark Scheme: Teachers’ version Syllabus Paper
2 (a) Mycobacterium tuberculosis / Mycobacterium bovis ; (1) (infected person) coughs / sneezes / spits / exhales / breathes out / aerosol (infection) / droplet (infection) / moist air (containing the pathogen) ; (uninfected person) inhales / breathes in / inspires ; ignore ref. to cattle treat ref. to virus etc as neutral (2) [3]
(b) 1 ref. patient does not complete course / takes inadequate dose / stops taking when
feels better ; 2 problems with continuing supply (of antibiotics) ; 3 not all bacteria killed ; 4 ref. mutation to become resistant ; R immune 5 likelihood of resistance increases if only one antibiotic used ; 6 ref. to changes in bacterium to enable resistance ; 7 ref. to changes in host cell (membrane structure) ; 8 AVP ; e.g. repeated exposure to different drug regimes (because of mp. 1) exposure to bacteria with different resistance [max 2]
(c) 1 ref. to, worldwide incidence of TB / TB found worldwide ; AW
2 highest, incidence / AW, (sub-Saharan) Africa / LEDC / developing countries ; 3 problem with, vaccine / BCG, qualified ; e.g. doesn’t work well, everywhere / in
Africa / in Far East doesn’t work well for all ethnic groups less efficient with age ref. cold chain / needs to be kept cold knowing when enough people vaccinated ref. to cost R vaccine doesn’t work 4 difficult to identify infected people / ref. symptomless carriers / AW ; 5 difficulty with, contact tracing / described ; 6 difficult to diagnose / time to diagnose (can infect others) ; 7 ref. to transmission from animals to humans ; 8 weakened immune systems / link with HIV/AIDS / TB is opportunistic ; 9 ref. social factor ; e.g. overcrowded living conditions, poor diet, remote areas 10 coordination of, vaccine / treatment ; 11 ref. to difficulty of administering, drugs / DOTS ; 12 lack / availability, of trained personnel ; 13 ref. to political problems ; e.g. war , unstable regimes, refugees, migration 14 cost, qualified with additional relevant point ; 15 AVP ; e.g. ref. to countries (e.g. Russia) with large area / low population density, 16 AVP ;ref. to quarantine problems, travel qualified, other social factor [max 5]
[Total: 10]
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Page 5 Mark Scheme: Teachers’ version Syllabus Paper
3 (a) (i) glucose and fructose ; ignore monosaccharides [1] (ii) 1 active site, gives specificity ; A specific active site
ignore ref to specific substrate 2 substrate binds with active site or enzyme-substrate / E-S, complex forms ; 3 complementary (shape) / substrate fits into active site ; A ‘lock and key’ A matching shape R ‘same shape’ 4 induced fit / described ; 5 further detail of substrate and active site ; e.g. binding by hydrogen bonding,
e.g. transfer of electrons 6 lowers activation energy / described e.g. causes strain in substrate / AW ;
A Ea 7 breaks glycosidic bond ; 8 glucose and fructose / products, no longer fit / AW ; [max 4]
concentration (in, companion cells / sink cells) ; maintains, concentration / diffusion, gradient (between phloem sieve tubes and, companion cells / sink cells) ; to remove sucrose from the phloem (sieve tubes) ; AVP ; e.g.ref. easier transport of, glucose / fructose, through membranes ; [max 2]
(ii) ref. facilitated diffusion out / may be lost from cells ;
products / glucose / fructose, are soluble / AW ; (so) will lower the water potential / water potential becomes more negative ; causes water to move into cells by osmosis ; A osmotic, problems / stress reactive / easily metabolised, qualified ; e.g. so interferes with, other metabolic processes / cell chemistry A more reactive than starch [max 3]
[Total: 11]
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Page 6 Mark Scheme: Teachers’ version Syllabus Paper
4 (a) R if mark points are in context of secondary response sensitised / activated / AW, by (foreign) antigen / epitope ; accept once only correct ref. specificity ; accept once only production of memory cells ; accept once only T lymphocytes (T-helper / Th) secrete, cytokines / lymphokines ; (T-helper / Th) stimulate, B cells to divide ; A stimulate humoral response (T-killer / Tk / T-cytotoxic / Tc) secrete, perforin / hydrogen peroxide / AW ; A toxins R hormones (T-killer / Tk / T-cytotoxic / Tc) kill / destroy / AW, non-self cells / pathogens / infected cells ; (T-surpressor / Ts) ref., surpresses / reduces, response (on recovery) ; B lymphocytes formation of plasma cells ; antibody production ; [max 4]
(b) no more antigen / AW ;
(remaining) antibodies, removed from the blood / broken down (in the liver) ; R excreted plasma cells, are short-lived / begin to die / are not replaced ; no more antibody produced ; AVP ; e.g. detail of removal / macrophage engulfs, digested, peptide bonds broken [max 3]
(c) line drawn continuous with that provided ;
and rising more steeply before day 55 ; should start to rise from day 40 / should rise more steeply initially /should not remain as a plateau from day 40 reaches higher than primary response between day 45-55 and, peaks / plateaus ; must not go below the day 40 antibody concentration [3]
[Total: 10]
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Page 7 Mark Scheme: Teachers’ version Syllabus Paper
5 (a) 1 thin (alveolar) walls / one cell thick / thin epithelium / squamous epithelium ; A pavement epithelium R thin cell wall R thin layer 2 short diffusion distance (between air and blood) ; 3 elastin / elastic fibres ; 4 stretch to increase surface area / increase surface area on inspiration / recoil to
expel air ; 5 ref. to maintaining, diffusion / concentration, gradient ; linked to marking points
above 6 large surface area for, diffusion / AW ; 7 some cells secrete surfactant ; 8 prevent collapse ; [max 3]
fewer alveoli ; A alveolar walls broken down / fewer air sacs / alveoli burst / alveoli destroyed / reduced surface area R elastin broken down or fewer capillaries ; effect less gas exchange / less uptake oxygen / less removal carbon dioxide ; [2]
(c) look for symptoms
shortness of breath / breathlessness / AW ; A breathing difficulty wheezing (on inspiration) ; rapid breathing rate / hyperventilation / decreased ability to hold breath ; R heavy breathing chest, tightness / pain ; cyanosis / bluish appearance to the skin / AW ; A pale fatigue / tiredness / lethargy / weakness / dizziness / reduced mobility / AW ; coughing / coughing up blood ; lots of / AW, mucus produced / much phlegm ; expanded / barrel, chest ; R refs to oxygen concentration of the blood R small vital capacity [max 3]
[Total: 9]
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Page 8 Mark Scheme: Teachers’ version Syllabus Paper
6 (a) (i) (for) chlorophyll (structure / synthesis) ; (for) ATP functioning ; (for) enzyme functioning / enzyme cofactor ; signalling ion / regulates carbon fixation ; (for) DNA / RNA, synthesis ; stabilises, DNA / RNA, structure ; A required in translation (matrix of) bone ; [max 1]
(ii) mutualistic association / AW ; A ref. to mycorrhiza
qualified; e.g. further detail of relationship, named nutrients arrow from plant to fungi ref. (some) fungi are, parasitic / pathogenic (on plants) ; A pathogens leakage (from plants) of assimilates ; arrow from fungi to plant plants absorb nutrients, excreted by fungi / from decomposition by fungi ; [2]
(b) (i) 5th / 6th ; A top carnivore [1] (ii) idea of little energy available, at / towards, top / end, of food chain ;
too few organisms in level below ; expend much energy catching animals in trophic level below ; to obtain, a wider range of / varied, nutrients ; reduced competition ; [max 2]
(c) (i) community
all, populations of all species / organisms, living in a particular area, at one time / AW ; (1) habitat place / location / environment / AW, where, a population / an organism, lives ; A community (1) [2]
(ii) soil is source of nutrients for, plants / producers ;
plants / producers, provide energy for ecosystems ; ref. recycling nutrients (by soil organisms) ; ref. to importance of, carbon / nitrogen, in, organic / complex molecules ; AVP ; e.g. detail of nutrient cycling, maintains balance of nitrogen in air [max 3]
[Total: 11]
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UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS
GCE Advanced Subsidiary Level and GCE Advanced Level
MARK SCHEME for the October/November 2010 question paper
for the guidance of teachers
9700 BIOLOGY
9700/31 Paper 31 (Advanced Practical Skills 1), maximum raw mark 40
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 must be read in conjunction with the question papers and the report on the examination.
• CIE will not enter into discussions or correspondence in connection with these mark schemes. CIE is publishing the mark schemes for the October/November 2010 question papers for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses.
www.maxpapers.com
Page 2 Mark Scheme: Teachers’ version Syllabus Paper
(ii) Identify two significant sources of error in your investigation. [2]
Reject temperature
Cause of error Error
1. 2. 3.
(dependent) timing /dropping/distance long pieces of potato ora shorter pieces (pieces of) potato
not accurate/delayed/different; different height to top there is shorter distance to surface longer distance to surface; stick to sides/bottom of tube don’t sink to bottom; [max 1]
4. 5. 6. 7.
(standardised variables) potato or position in potato or age or storage water left on potato (test)-tubes hydrogen peroxide
not same different/variety old; not same/different; not same size/height; concentration changes/decreases evaporates/degenerates/breaksdown; [max 1]
(below 7 or above 7) do not accept collision(s)/react fewer ECSs (enzyme substrate complexes) or less/no substrate can bind/combine/attach fit into enzyme/active site; [1]
AC
E c
on
clu
sio
n 3
(below 7/above 7) (enzymes) denatured; [1]
[Total: 20]
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Page 7 Mark Scheme: Teachers’ version Syllabus Paper
2 Make a large, high-power drawing to show the details of five of the structures specialised for gas exchange (alveoli). The walls of one alveolus must be touching the walls of at least two other alveoli. Label where gas exchange takes place. [5]
Reject if drawn over the print of question
Reject
• thick lines
• feathery lines
• 2 ‘tails’ or overlaps or gaps
PD
O l
ay
ou
t 1
1.
clear, sharp, unbroken continuous lines
AND no shading
AND use most of the space provided; [1]
2. five structures drawn AND at least 3 structures touching; [1]
MM
O
co
lle
cti
on
2
3. at least three alveoli different shapes/sizes
AND thickness of one wall irregular; [1]
4. (walls with) at least 2 cells drawn
AND at least one nucleus drawn; [1]
MM
O d
ec
isio
ns
2
5. Reject
• if any label is biologically incorrect e.g. cell wall.
• label within drawn area
• into centre of alveolus correct label with label line to wall of alveolus; [1]
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Page 8 Mark Scheme: Teachers’ version Syllabus Paper
(ii) Calculate the ratio of the mean thickness of the outer layer of the bronchiole compared to the mean thickness of the wall of the blood vessel shown in Fig. 2.1. [4]
Reject If lines not shown on both bronchiole and blood vessel
shows one measurement on each of bronchiole and blood vessel; [1]
Reject If no units If not both same units If metres or converted to metres or micrometres or standard form M
MO
co
lle
cti
on
2
(one bronchiole measured) to nearest 0.5 mm
AND mm; [1]
shows mean adds measurements
AND shows division by number of measurements; [1]
MM
O d
ec
isio
ns
2
Reject
• If given as decimal :1
• If smaller to larger number
• If include units answer is larger whole number to smaller whole number or leaves as fraction;
[1]
Either must be to lowest common denominator
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Page 10 Mark Scheme: Teachers’ version Syllabus Paper
(iii) Prepare the space below so that it is suitable for you to compare the observable features of the bronchiole and blood vessel in the photomicrograph Fig. 2.1. [6]
organise as a table/ Venn diagram/ ruled boxes
AND headed bronchiole and blood vessel
AND differences opposite each other;
[1]
bronchiole blood vessel
PD
O r
ec
ord
ing
2
heading for similarities/similarity/compare (with contrast)/same; [1]
If no organisation if in same sentence or following sentences.
[Total: 20]
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UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS
GCE Advanced Subsidiary Level and GCE Advanced Level
MARK SCHEME for the October/November 2010 question paper
for the guidance of teachers
9700 BIOLOGY
9700/33 Paper 31 (Advanced Practical Skills 1), maximum raw mark 40
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 must be read in conjunction with the question papers and the report on the examination.
• CIE will not enter into discussions or correspondence in connection with these mark schemes. CIE is publishing the mark schemes for the October/November 2010 question papers for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses.
www.maxpapers.com
Page 2 Mark Scheme: Teachers’ version Syllabus Paper
[1] In correct context of increasing or just copper sulfate Idea of damages or destroys or makes more denatures (increases copper sulfate) increases (decreases copper sulfate) decreases (increases copper sulfate) decreases (decreases copper sulfate) increases
it or ((cell) membrane(s)) phospholipid(s) fluid mosaic (model/structure) (fully) permeable protein fluidity permeability selective permeability;
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Page 4 Mark Scheme: Teachers’ version Syllabus Paper
(vi) Identify three significant sources of error in your investigation. [3]
Reject temperature pH evaporation any errors which affect all test-tubes equally
Cause of error Error
[1]
(dependent) qualitative;
[1] [1] [1]
colour/colour change/observations mixing
difficult judging seeing; qualitative; more difficult to judge colour/colours the same;
AC
E i
nte
rpre
tati
on
MA
X 3
[1] [1] [1] [1]
(standardised variables) potato or position in potato or age or storage lengths/size/surface areas/volumes Allow mass staining/washing/handling/forceps potato/samples (into test-tubes)
not same different/variety old; not same; not same loses stain damages potatoes ends not stained or middle more stain; time not same/delayed time/not at same time; max 3
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Page 5 Mark Scheme: Teachers’ version Syllabus Paper
(ii) Make a high-power drawing of one large xylem vessel and the single layer of cells touching a quarter of the vessel’s circumference. Labels are not required. [5]
Reject
• if drawn over the print of question
Reject
• thick lines – than on grid
• feathery lines
• 4 ‘tails’ or overlaps or gaps if double lines for all cells
• 1 if single line for any cell
PD
O l
ay
ou
t 1
[1]
clear, sharp, unbroken lines
AND no shading
AND uses most of space provided;
[1] one xylem vessel drawn Ignore band inside
AND only single layer of surrounding cells ;
Reject if layer of cells all round xylem vessel If xylem vessel not circular/polygonal
[1]
(surrounding cells) (single layer) three to eight cells in a layer only; Allow not touching.
Reject any spaces if single line for cell walls. any gaps between cell walls – floating cells
MM
O c
oll
ec
tio
n 3
[1]
(all cells including xylem vessel) no enclosed spaces more than 1mm between adjacent double cell walls;
PD
O
rec
ord
ing
1
[1] cell walls drawn as double lines with middle lamella between three adjacent cells from surrounding cells;
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Page 8 Mark Scheme: Teachers’ version Syllabus Paper
(c) (i) Plot a chart of the data shown in Table 2.1. [4] MAX 2 for O and S if line graph drawn
O [1]
x-axis content(s) AND y-axis conc(entration in) phloem or sieve tube/element (/)
µg cm 3;
Must have units
Reject scale on y-axis any other than 20 to 2 cm.
S [1]
scale as even widths to 2 cm
AND y-axis 20 to 2 cm;
Reject if y-axis scale is awkward if bars arranged differently from order of
table if horizontal lines are too thick – 1mm/half
square or not clear Allow bars if scale 20 to 2 cm. even if not 0 25 to 2 cm
P
[1] correct plotting of each bar;
horizontal top line must be clear, sharp and ruled to show plot line must be on horizontal line for sucrose line must be between two lines for all other contents
PD
O l
ay
ou
t 4
L [1]
each bar separate if vertical lines only then must be at least 1 cm apart.
AND quality – vertical lines no thicker than on grid, not feathery for the complete line; bars –
• ruled lines Reject irregular thickness
• labelled clearly with contents – any clear labels e.g. chemical formulae NH4, Ca, Mg, Na or mixture – underneath, must be directly below correct bar or inside bar or shaded with key.
Reject solid shading If line shading outside a bar
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Page 10 Mark Scheme: Teachers’ version Syllabus Paper
(ii) Calculate the percentage difference between the concentration of calcium ions in the xylem vessels and the concentration of calcium ions in the phloem sieve tube elements. [2]
[1] shows subtraction (190 – 85) divided by 190 multiplied by 100; (190/190 – 85/190) × 100 or (1 – 85/190) × 100
PD
O d
isp
lay
2
[1] Reject if no working Allow any answer less than 100 to no more than 3 significant figures 1 decimal place
AND percentage/%;
(d) Suggest why there is 120 µg cm–3 of sucrose in the phloem sieve tube elements. [2]
[1] (phloem sieve tube elements) (sucrose) transported leaf(ves)/allow type of leaf cell/source to roots/other tissues/sink(s);
AC
E c
on
clu
sio
ns
MA
X 2
[1]
(detail) load(ed) (in source) or (transported by) mass flow/bulk transport/translocation (sucrose) too large to move out of phloem or sieve tubes or xylem walls impermeable;
[Total: 22]
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UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS
GCE Advanced Subsidiary Level and GCE Advanced Level
MARK SCHEME for the October/November 2010 question paper
for the guidance of teachers
9700 BIOLOGY
9700/34 Paper 32 (Advanced Practical Skills 2), maximum raw mark 40
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 must be read in conjunction with the question papers and the report on the examination.
• CIE will not enter into discussions or correspondence in connection with these mark schemes. CIE is publishing the mark schemes for the October/November 2010 question papers for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses.
www.maxpapers.com
Page 2 Mark Scheme: Teachers’ version Syllabus Paper
1 (a) (i) Show clearly on Fig.1.1 what you would expect the contents of the test-tube to look like after 10 minutes. You will gain marks for clear labels. [2]
[1] line drawn level with half way mark AND more yeast drawn towards bottom of tube or another line to show a separate region;
AC
E
co
nc
lus
ion
s 2
[1] one label or description;
(ii) State the time intervals you will use and what you will use the graph paper scale to measure. [2]
uses 10 minutes AND at least three times (including 10) even time intervals between consecutive three;
[1]
Or one/two/two and a half minutes or two mins 30s intervals; Reject if does not divide into 10 e.g. 3 minutes
MM
O d
ec
isio
ns
2
[1] measures or describes measuring e.g. (use graph paper) to find distance/length
AND description of what is measured; e.g. from halfway mark to top of sediment or bottom of tube to top of sediment/or from Fig. 1.1/AW;
(iii) …decide on the volume of Y and the volume of each buffer solution to use. Describe all the steps you used to work out the volume. [1]
State the volume of Y and the volume of each buffer solution to use. [1]
[1] describes all following steps
• takes into account to (half-way) line
• takes into account 1 cm3 calcium chloride/C
• divides by half;
MM
O d
ec
isio
ns
2
[1] volume of Y equal to volume of buffer AND cm3 / ml on both;
Allow
• to 0.1 cm3
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Page 3 Mark Scheme: Teachers’ version Syllabus Paper
(vii) Suggest how you could make this investigation as accurate as possible … as reliable as possible [3]
C control of any relevant variable; [1] [1]
(for volumes) use measuring cylinder/burette/graduated pipettes or tubes or smaller (divisions)syringes Or hold tube vertical in retort stand/attach graph paper to tubes;
A1 improving measurements to get a true value [1]
use ruler/graph paper, with smaller divisions/vernier calipers or colorimeter or collect and dry sediment or larger/more volumes so heights larger;
A2 [1]
set up each pH separately/stagger timing/longer time;
A3 [1]
more buffer solutions or examples of extra buffer/pH;
R1 improve method to get repeat data [1]
repeat or replicate;
AC
E i
mp
rov
em
en
ts m
ax
3
R2 [1]
weigh out (initial) mass of yeast ;
Allow for either accuracy or reliable
max 3
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Page 6 Mark Scheme: Teachers’ version Syllabus Paper
(ii) Make a high-power drawing of one trichome, with at least three cells, and one epidermal cell on each side touching the base of the trichome. Label the trichome. [5]
Reject if drawn over print of question
Reject
• thick lines – than on grid
• feathery lines
• 5 ‘tails’ or overlaps or gaps if double cell walls PD
O l
ay
ou
t 1
[1]
clear, sharp, unbroken lines in cell outlines
AND no shading
AND uses most of the space provided;
[1] 5, 6 or 7 cells;
MM
O
co
lle
cti
on
2
[1] cells drawn as a touching group AND cell walls as double lines with middle lamella in 3 adjacent (epidermal) cells;
[1] (cell or tip of trichome or broken) pointed or rounded Or (in trichome) one larger cell or large base cell;
Reject
• if any label is biologically incorrect e.g. labels belonging to other organs or animals.
• label within drawn area MM
O d
ec
isio
ns
2
[1]
correct label with label line to trichome;
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Page 9 Mark Scheme: Teachers’ version Syllabus Paper
if no organisation then mark points only if in same sentence or following sentences. Allow differences even if not opposite each other. Allow difference on one side if e.g. use more or –er. max 4
[Total: 18]
www.maxpapers.com
UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS
GCE Advanced Subsidiary Level and GCE Advanced Level
MARK SCHEME for the October/November 2010 question paper
for the guidance of teachers
9700 BIOLOGY
9700/35 Paper 31 (Advanced Practical Skills 1), maximum raw mark 40
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 must be read in conjunction with the question papers and the report on the examination.
• CIE will not enter into discussions or correspondence in connection with these mark schemes. CIE is publishing the mark schemes for the October/November 2010 question papers for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses.
www.maxpapers.com
Page 2 Mark Scheme: Teachers’ version Syllabus Paper
[1] scale as 0.02% to 2 cm AND sensible volume to 2 cm and uses more than half
grid;
Reject plotting if scale awkward if only blobs/dots/blobs in circles if extra plot for X value
P
[1] correct plotting using crosses/dots in circle only;
intersection of cross must be clear to show plot.
PD
O l
ay
ou
t 4
L [1]
straight line through points; error carried forward if scale or plotting incorrect
quality – no thicker than on grid, not feathery for the complete line.
joining plots –
• ruled lines plot to plot
• line of best fit two plots plus even plots (+1) either side or even plots either side
• curve through all plots
line of best fit must end either at the horizontal line or the vertical line for each of the end plots i.e. highest and lowest concentration Reject if any extrapolation
(iv) Use your graph to estimate the ascorbic acid concentration of sample X. Show clearly on your graph how you obtained the ascorbic acid concentration. [3]
MM
O
co
lle
cti
on
1
[1] shows clearly on graph result for X e.g. as single line from volume for X or as extra plot;
[1] correct reading of ascorbic acid concentration
AND answer to no more than 4 decimal places or three significant figures if 4 decimal places last figure must be 5 (or 0); A
CE
inte
rpre
tati
on
2
[1] %;
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Page 4 Mark Scheme: Teachers’ version Syllabus Paper
(v) Identify two significant sources of error when finding the concentration of ascorbic acid in sample X. [2]
cause of error error
[1]
[1]
(dependent variables) drops stick to sides too many drops volume for Y colour change or same colour
idea of volume/number of drops/not counted/not included/too high/not accurate too many at once/end-point missed too small judging determining seeing when;;
[1]
[1]
[1]
(standardised variables) drop size/different pressure on syringe/syringe sticking/ mixing iodine evaporating/exposed to light
not same/vary/different;
AC
E i
nte
rpre
tati
on
ma
x 2
[1]
[1]
(independent variable) (ascorbic acid) evaporates or mixes with air concentrations
changes concentration/reacts; more/wider/narrower/different needed; max 2
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Page 5 Mark Scheme: Teachers’ version Syllabus Paper
(vi) Suggest how you would make three improvements to this investigation. [3]
[1] more/wider/narrower/different/examples range of concentrations (ascorbic acid) use graduated pipette or smaller/more divisions/calibration syringe/burette;
[1] device/described for making drops/burette/titrate;
[1] (to identify the end-point) use colorimeter or have a standard colour to compare to or use white tile/paper;
[1] put drops in nearer to mixture or use a smaller test-tube/container or use a wider/larger test-tube/beaker/AW;
AC
E i
mp
rov
em
en
ts m
ax
3
[1] replicate/repeat/take more readings (each concentration); max 3
[Total: 21]
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Page 6 Mark Scheme: Teachers’ version Syllabus Paper
2 (a) (i) Draw a large plan diagram of the sector shown in Fig. 2.1 to include the outline of two vascular bundles. No details of the internal tissues of the vascular bundles are required. [5]
Reject
• if drawn over the print of question
Reject
• thick lines
• feathery lines
• 3 ‘tails’ or overlaps or gaps PD
O l
ay
ou
t 1
[1] clear, sharp, unbroken lines
AND no shading
AND uses most of the space provided;
[1] no cells drawn AND only two vascular bundles drawn in outline only;
MM
O
co
lle
cti
on
2
[1] rounded/pointed end;
[1] longest vascular bundle is less than half width at widest point of section;
Reject
• if any label is biologically incorrect e.g. cell wall or regions belonging to other organs or animals.
• additional label(s) within drawn area
MM
O d
ec
isio
ns
2
[1] correct label C (can be within drawn area) to tissue below upper or lower epidermis;
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Page 7 Mark Scheme: Teachers’ version Syllabus Paper
(d) Describe how the observable features of Fig.2.2 support the conclusion that this is a leaf from a plant growing in a dry habitat. [3]
[1] sunken stomata or rolled/rounded to reduce the diffusion of water/decreases diffusion gradient;
[1] thick cuticle or thickened epidermis
to prevent or reduce evaporation of water;
[1] no spongy mesophyll layer or no air spaces
to prevent evaporation from cell walls;
AC
E c
on
clu
sio
n M
AX
3
[1] rounder shape or rolled or fewer stomata smaller surface area to volume ratio
to increase humidity/decreases diffusion gradient;
[1] (in context of any of above) reduces transpiration (rate); max 3
[Total: 19]
www.maxpapers.com
UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS
GCE Advanced Subsidiary Level and GCE Advanced Level
MARK SCHEME for the October/November 2010 question paper
for the guidance of teachers
9700 BIOLOGY
9700/36 Paper 32 (Advanced Practical Skills 2), maximum raw mark 40
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 must be read in conjunction with the question papers and the report on the examination.
• CIE will not enter into discussions or correspondence in connection with these mark schemes. CIE is publishing the mark schemes for the October/November 2010 question papers for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses.
www.maxpapers.com
Page 2 Mark Scheme: Teachers’ version Syllabus Paper
1 (a) (i) Decide on the temperatures you plan to use in the range (between) 25°C to 45°C. Record the temperatures you have chosen in the space below. [2]
[1] at least 5 temperatures;
MM
O
de
cis
ion
s 2
[1] one temp. 25°C to 29°C AND one temp 40°C to 45°C
AND any three with two even intervals 3 or more degrees;
(ii) Prepare the space below and record your results. [4]
Reject
• if any units in body of table
• only t
[1]
table with all cells drawn AND heading (top or left) temperature °C; Must have units
PD
O r
ec
ord
ing
2
[1] Reject
• if units in body of table
• if headings for volumes or stages (heading) time with units;
[1] temperatures recorded highest to lowest
AND first set of times recorded in whole seconds;
MM
O
co
lle
cti
on
2
[1] time at the lowest temperature is greater than the next temperature; Allow
• only if 3 or more results
(iii) From your results, state the temperature at which the activity of the enzyme is lowest. [1]
AC
E
inte
rpre
tati
on
1
[1] temperature with longest time AND with units, °C;
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Page 3 Mark Scheme: Teachers’ version Syllabus Paper
(vi) Suggest how you could make this investigation as reliable as possible. [1]
C control of any relevant variable
[1]
equilibrate milk and enzyme to temp. separately then mix Or use thermostatically controlled water bath Or keep tube in water bath during rotation;
AC
E i
mp
rov
em
en
ts M
AX
1
R1 improve method to get repeat data [1]
repeat AND calculate or find mean/average;
max 1
(b) (i) Three of the values in Table 1.1 are anomalous. Draw a circle around each of these values. [1] (ii) Complete the Table 1.1 by calculating the missing value. [1]
[1]
MM
O d
ec
isio
ns
1
AC
E i
nte
rpre
tati
on
1
[1]
circles around 8.2, 4.9, 1.1;
8.8 Allow 8.7
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Page 5 Mark Scheme: Teachers’ version Syllabus Paper
[1] (in correct context of increase in pH and decrease activity) so fewer enzyme-substrate complexes (ESCs) or less/no substrate can bind/combine/attach/fit into OR (in context of decrease in pH and increase in activity) more ESCs or more substrate binds/attaches;
AC
E c
on
clu
sio
ns
3
[1] (in correct context of effect of pH on enzyme i.e. when pH higher/nearer 7/less acidic/more alkaline) denatured/denaturation;
[Total: 20]
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Page 7 Mark Scheme: Teachers’ version Syllabus Paper
(ii) Annotate (make notes with label lines) your diagram to show one difference between the outside layers and the inside layers. [1]
MM
O d
ec
isio
n m
ax
1
[1]
[1]
[1]
[1]
Reject
• if written over lines of the diagram drawing.
• if written underneath, unless have labelled on diagram Allow ‘er’ for one label
max 1
(b) (i) Actual diameter of the nucleus in the cell labelled Y is 7.8 µm. Use this information to calculate the actual diameter of the largest nucleolus in cell Y. [4]
[1] correct measurement of one nucleus, 11 to 15 mm; Reject if no units
MM
O
co
lle
cti
on
2
[1] correct measurement of one nucleolus, 2 to 4.5 mm; Reject if no units
[1] (mean) adds three measurements AND shows division by 3;
PD
O
dis
pla
y
2
[1] answer to no more than 2 significant figures, (1 decimal place) between 1.1 and 6.4; Reject standard form
outermost innermost
thickness Reject cell wall
thin)ner) think(er);
texture smooth rough;
cells/nuclei Not clear/densely packed/ visible
Clear/less densely packed/(air) spaces/lots
Colours/staining of l
Pink/red/grey/lighter/more Purple/darker/less;
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Page 9 Mark Scheme: Teachers’ version Syllabus Paper
(ii) Suggest how you would make the measurement of each nucleolus more accurate. [1]
AC
E i
mp
rov
em
en
t 1
[1] different dimensions/diameters or use vernier callipers or (eyepiece) graticule or increase magnification or high power (of microscope) or enlarging or increase resolution;
(iii) Make a large drawing of the cell labelled X with three complete cells touching cell X. [5]
Reject if drawn over print of question
Reject
• thick lines
• feathery lines
• 2 ’tails’ or overlaps or gaps
PD
O l
ay
ou
t 1
[1]
clear, sharp, unbroken lines
AND no shading
AND uses most of space provided;
[1] only cell X and three correct complete touching cells;
MM
O c
oll
ec
tio
n 2
[1] nucleus with at least two distinct nucleoli (other than cell X);
[1] chromosomes drawn as two areas (no details of chromosomes shown);
MM
O
de
cis
ion
s 2
[1] blue region/spindle around chromosomes drawn in cell X;
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Page 10 Mark Scheme: Teachers’ version Syllabus Paper
if no organisation then mark points only if in same sentence or following sentences. Allow two ticks for both present i.e. for cytoplasm and shape. Allow differences even if not opposite each other. Allow difference on one side if e.g. use more or –er. max 2
[Total: 20]
X Y
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UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS
GCE Advanced Subsidiary Level and GCE Advanced Level
MARK SCHEME for the October/November 2010 question paper
for the guidance of teachers
9700 BIOLOGY
9700/41 Paper 4 (A2 Structured Questions), maximum raw mark 100
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 must be read in conjunction with the question papers and the report on the examination.
• CIE will not enter into discussions or correspondence in connection with these mark schemes. CIE is publishing the mark schemes for the October/November 2010 question papers for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses.
www.maxpapers.com
Page 2 Mark Scheme: Teachers’ version Syllabus Paper
Mark scheme abbreviations: ; separates marking points / alternative answers for the same point R reject A accept (for answers correctly cued by the question or guidance on the mark scheme) AW alternative wording (where responses may vary more than usual) underline actual word given must be used by the candidate (grammatical variants excepted) max indicates the maximum number of marks that can be given ora or reverse argument
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Page 3 Mark Scheme: Teachers’ version Syllabus Paper
mallard numbers have increased and the others have decreased ; decrease due to pesticides / pollution / fertilisers ; change in temperature or pH of water ; lack of named food source ; increased competition / AW ; direct human interference on lake ; e.g. fishing / sailing etc not related to marking point 2 mallard increase due to doesn’t eat, insects / molluscs / fish ; less other birds so less competition ; [4 max]
(b) 1 2 3 4 5 6 7 8 9 10
cultural / aesthetic / leisure, reasons ; moral / ethical, reasons ; e.g. right to exist / prevent extinction resource material ; e.g. wood for building / fibres for clothes / food for humans ecotourism ; economic benefits ; ref. resource / species, may have use in future / AW ; e.g. medical use maintains, food webs / food chains ; A description nutrient cycling / protection against erosion ; climate stability ; maintains, large gene pool / genetic variation ;
[4 max]
[Total: 8]
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Page 4 Mark Scheme: Teachers’ version Syllabus Paper
2 (a) (i) 1 penicillin inhibits, enzyme / peptidase ; 2 blocks / alters shape of, active site ; 3 peptidoglycan chains cannot link up / stops cross-links forming ; 4 cell wall weaker / AW ; 5 turgor of cell not resisted (by cell wall) / AW ; 6 cell / wall / bacterium, bursts ; [3 max]
(ii) any two from 1 viruses do not have cell wall ; 2 viruses do not have cytoplasm ; 3 viruses do not have peptidoglycan ; 4 viruses do not have peptidase ; [2 max]
(b) 1 2 3 4 5
without antibiotic numbers of both wild-type and mutant strains, increase / hardly changes ; with antibiotic numbers of both wild-type and mutant strains decrease ; mutant strains decrease more than wild-type ; A faster this subsumes marking point 2 after 24h, wild-type plateaus and mutant strain continues to decrease ; ref. comparative figures at any one time ; ignore units for bacteria blue with blue red with red red with blue – with antibiotic [4 max]
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Page 5 Mark Scheme: Teachers’ version Syllabus Paper
(c) (i) 1 changes in, base / nucleotide, sequence ; A named change e.g. substitution 2 alters, triplet code / codon ; 3 enzyme has different, primary structure / amino acid sequence ; 4 enzyme has different, 3D structure / tertiary structure / active site ; [2 max]
(ii) red and blue with antibiotic 1 wild-type bacteria can produce glucans or mutant bacteria produce less glucans ; 2 glucans bind with antibiotic ; 3 wild-type more resistant to antibiotic or mutant bacteria less resistant to
antibiotic ; [2 max]
(d) 1 2 3 4
antibiotic, is selective agent / provides selective pressure ; resistant bacteria, survive / reproduce ; pass allele for resistance to offspring ; frequency of allele in population increases ; [3 max]
[Total: 16]
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Page 6 Mark Scheme: Teachers’ version Syllabus Paper
to give superovulation ; follicles or oocytes, mature or develop, at the same time ; ignore grow to prepare uterus for implantation ; [2 max]
(b) 1 2 3 4
germinal epithelial cell divides by mitosis ; giving oogonia ; primary oocyte divides by meiosis I (to give a secondary oocyte) ; idea of diploid to haploid [3 max]
(c) advantage ensure sperm enters oocyte / select (visibly) healthy sperm ; disadvantage unneeded parts of sperm enter producing unwanted effects or cannot tell whether a chosen sperm is genetically suitable ; [2]
[Total: 7]
4 (a) 1 2 3 4 5
binds to receptors (on liver cell membranes) ; conversion of glucose to glycogen / glycogenesis ; (because) insulin activates enzyme ; e.g. glucokinase / phosphofructokinase / glycogen synthase increased use of glucose in respiration ; increased uptake of glucose / increased permeability to glucose (of liver cells) ; [3 max]
(b) (i) 1 mRNA (found in β cells) is only from gene coding for insulin / AW ; 2 large numbers (of mRNA coding for insulin) ; 3 (whereas) DNA has all genes ; 4 (so) restriction enzymes needed ; [2 max]
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Page 7 Mark Scheme: Teachers’ version Syllabus Paper
(ii) 1 cut plasmid (DNA) ; 2 at specific, base sequence / site ; 3 leaving sticky ends (that will join with insulin gene) ; [2 max]
(c) (i) all statements must be comparative inhaled (accept ora for injected) 1 insulin concentration rises more rapidly when inhaled ; 2 higher peak ; 3 falls, more rapidly / earlier ; 4 (after 150 mins) lower (than injected) ; 5 use of comparative figures ; figures for both at one time [3 max]
(ii) 1 glucose conc. is linked to insulin conc. ; inhaled (accept ora for injected) 2 (initially) glucose falls because insulin conc. rises ; this subsumes marking point 1 3 glucose conc. falls lower because insulin conc. is higher ; this subsumes marking point 1 4 (later) glucose rises higher because insulin conc. is lower ; this subsumes marking point 1 5 use of figures ; e.g. one glucose conc. for inhaled and one for injected at one time or one glucose conc. linked to an insulin conc. at one time (either inhaled or injected) [3 max]
(iii) advantages: 1 faster response time ; 2 less chance of, infection / contamination ; 3 good for people with needle phobia ; max 1 disadvantages : 4 could cause larger swings in blood glucose concentration ; 5 may need to taken more often / not long lasting ; 6 possible variability of dose / AW ; max 1 [2 max]
[Total:15]
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Page 8 Mark Scheme: Teachers’ version Syllabus Paper
oxygen availability low (when soil is flooded) ; plants carry out anaerobic respiration ; ethanol produced ; roots can continue to respire ; [2 max]
(b) (i) (store of) nutrients ; A named nutrient ignore food / water / fibre for, germination / growth of embryo ; [2]
(ii) protein in aleurone layer ; which is removed in white rice ; ora [2]
(iii) endosperm makes up a greater proportion of the total mass in white rice ; or brown rice has more, lipid / fibre / protein, than white rice so less carbohydrates per gram ; [1 max]
(iv) 1 cheap source of food ; 2 high, energy value / fibre content ; 3 high in carbohydrate ; 4 contain wide range of nutrients or three named nutrients ; 5 cereal grains store well ; 6 because they contain very little water ; [2 max]
[Total: 9]
6 (a) variation / different form, of a gene ; [1]
(b) marks for reasons only HbA HbA
low – susceptible to / die from, malaria ; HbA HbS high – no (full blown) SCA / have SC trait ; not, susceptible to / likely to die from, malaria ; HbS HbS low – susceptible to / die from, SCA ; [4]
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Page 9 Mark Scheme: Teachers’ version Syllabus Paper
USA malaria not selection pressure ; HbS no advantage ; due to outbreeding ; genetic testing can lead to termination of pregnancy or testing / counselling, leads to not having children ; [2 max]
[Total: 7]
7 (a) 1 2 3 4
apical bud is source of auxin ; auxin inhibits growth of side shoot ; remove bud and auxin conc falls ; this allows cell, division / elongation, to take place (in side shoots) ; [3 max]
(b) 267 ;; accept suitable working for one mark e.g. 110 – 30 (× 100) 30 or accept 266.7 for one mark [2]
(c) D1 E2 E3 D4 E5 D6
days 2 to 8 no increase in length with paste plus auxin (compared to control) ; auxin moves from paste into plants ; inhibits growth ; days 8 to 13 increase in length occurs (with paste and auxin) ; less auxin left ; supportive figs ; e.g. two blue points on two days plus units or one red and one blue point on same day plus units must have at least one D (description) and one E (explanation) to score 3 marks [3 max]
[Total: 8]
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Page 10 Mark Scheme: Teachers’ version Syllabus Paper
absorb light ; A harvest light / trap light R collect light pass energy to, primary pigment / chlorophyll / reaction centre ; [2 max]
(b) 1 2 3 4 5 6
cyclic photophosphorylation electron emitted returns to, PSI / same photosystem or same chlorophyll molecule ; non-cyclic photophosphorylation electron emitted from PSII absorbed by PSI ; reduced NADP produced ; photolysis occurs ; A splitting of water (photolysis) only involves PSII ; oxygen produced 3 max accept ora for cyclic for marking points 3, 4 and 6 mark to max 3 if cyclic and non-cyclic are described the wrong way round [4 max]
(c) (i) some other factor becomes limiting / temperature no longer limiting ; CO2 / light intensity ; [2]
(ii) line falls towards 70oC ; [1]
(iii) rate of photosynthesis falls enzyme / rubisco, denatured / AW ; substrates not able to fit active site / AW ; [2]
(d) adaptation how the adaptation helps photosynthesis
idea of lipid > protein > carbohydrate / AW ; A lipid has more energy than either protein or carbohydrate comparative figures ; e.g. 39.4, 17.0 and 15.8 accept any two kJ g 1 / per unit mass ; more hydrogen atoms in molecule, more energy ; lipid have more, hydrogen atoms / C-H bonds ; (most) energy comes from oxidation of hydrogen to water ; using reduced, NAD / FAD ; in ETC ; detail of ETC ; ATP production
[6 max]
[Total: 15]
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UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS
GCE Advanced Subsidiary Level and GCE Advanced Level
MARK SCHEME for the October/November 2010 question paper
for the guidance of teachers
9700 BIOLOGY
9700/42 Paper 4 (A2 Structured Questions), maximum raw mark 100
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 must be read in conjunction with the question papers and the report on the examination.
• CIE will not enter into discussions or correspondence in connection with these mark schemes. CIE is publishing the mark schemes for the October/November 2010 question papers for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses.
www.maxpapers.com
Page 2 Mark Scheme: Teachers’ version Syllabus Paper
Mark scheme abbreviations: ; separates marking points / alternative answers for the same point R reject A accept (for answers correctly cued by the question or guidance on the mark scheme) AW alternative wording (where responses may vary more than usual) underline actual word given must be used by the candidate (grammatical variants excepted) max indicates the maximum number of marks that can be given ora or reverse argument
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Page 3 Mark Scheme: Teachers’ version Syllabus Paper
mallard numbers have increased and the others have decreased ; decrease due to pesticides / pollution / fertilisers ; change in temperature or pH of water ; lack of named food source ; increased competition / AW ; direct human interference on lake ; e.g. fishing / sailing etc not related to marking point 2 mallard increase due to doesn’t eat, insects / molluscs / fish ; less other birds so less competition ; [4 max]
(b) 1 2 3 4 5 6 7 8 9 10
cultural / aesthetic / leisure, reasons ; moral / ethical, reasons ; e.g. right to exist / prevent extinction resource material ; e.g. wood for building / fibres for clothes / food for humans ecotourism ; economic benefits ; ref. resource / species, may have use in future / AW ; e.g. medical use maintains, food webs / food chains ; A description nutrient cycling / protection against erosion ; climate stability ; maintains, large gene pool / genetic variation ;
[4 max]
[Total: 8]
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Page 4 Mark Scheme: Teachers’ version Syllabus Paper
2 (a) (i) 1 penicillin inhibits, enzyme / peptidase ; 2 blocks / alters shape of, active site ; 3 peptidoglycan chains cannot link up / stops cross-links forming ; 4 cell wall weaker / AW ; 5 turgor of cell not resisted (by cell wall) / AW ; 6 cell / wall / bacterium, bursts ; [3 max]
(ii) any two from 1 viruses do not have cell wall ; 2 viruses do not have cytoplasm ; 3 viruses do not have peptidoglycan ; 4 viruses do not have peptidase ; [2 max]
(b) 1 2 3 4 5
without antibiotic numbers of both wild-type and mutant strains, increase / hardly changes ; with antibiotic numbers of both wild-type and mutant strains decrease ; mutant strains decrease more than wild-type ; A faster this subsumes marking point 2 after 24h, wild-type plateaus and mutant strain continues to decrease ; ref. comparative figures at any one time ; ignore units for bacteria blue with blue red with red red with blue – with antibiotic [4 max]
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Page 5 Mark Scheme: Teachers’ version Syllabus Paper
(c) (i) 1 changes in, base / nucleotide, sequence ; A named change e.g. substitution 2 alters, triplet code / codon ; 3 enzyme has different, primary structure / amino acid sequence ; 4 enzyme has different, 3D structure / tertiary structure / active site ; [2 max]
(ii) red and blue with antibiotic 1 wild-type bacteria can produce glucans or mutant bacteria produce less glucans ; 2 glucans bind with antibiotic ; 3 wild-type more resistant to antibiotic or mutant bacteria less resistant to
antibiotic ; [2 max]
(d) 1 2 3 4
antibiotic, is selective agent / provides selective pressure ; resistant bacteria, survive / reproduce ; pass allele for resistance to offspring ; frequency of allele in population increases ; [3 max]
[Total: 16]
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Page 6 Mark Scheme: Teachers’ version Syllabus Paper
to give superovulation ; follicles or oocytes, mature or develop, at the same time ; ignore grow to prepare uterus for implantation ; [2 max]
(b) 1 2 3 4
germinal epithelial cell divides by mitosis ; giving oogonia ; primary oocyte divides by meiosis I (to give a secondary oocyte) ; idea of diploid to haploid [3 max]
(c) advantage ensure sperm enters oocyte / select (visibly) healthy sperm ; disadvantage unneeded parts of sperm enter producing unwanted effects or cannot tell whether a chosen sperm is genetically suitable ; [2]
[Total: 7]
4 (a) 1 2 3 4 5
binds to receptors (on liver cell membranes) ; conversion of glucose to glycogen / glycogenesis ; (because) insulin activates enzyme ; e.g. glucokinase / phosphofructokinase / glycogen synthase increased use of glucose in respiration ; increased uptake of glucose / increased permeability to glucose (of liver cells) ; [3 max]
(b) (i) 1 mRNA (found in β cells) is only from gene coding for insulin / AW ; 2 large numbers (of mRNA coding for insulin) ; 3 (whereas) DNA has all genes ; 4 (so) restriction enzymes needed ; [2 max]
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Page 7 Mark Scheme: Teachers’ version Syllabus Paper
(ii) 1 cut plasmid (DNA) ; 2 at specific, base sequence / site ; 3 leaving sticky ends (that will join with insulin gene) ; [2 max]
(c) (i) all statements must be comparative inhaled (accept ora for injected) 1 insulin concentration rises more rapidly when inhaled ; 2 higher peak ; 3 falls, more rapidly / earlier ; 4 (after 150 mins) lower (than injected) ; 5 use of comparative figures ; figures for both at one time [3 max]
(ii) 1 glucose conc. is linked to insulin conc. ; inhaled (accept ora for injected) 2 (initially) glucose falls because insulin conc. rises ; this subsumes marking point 1 3 glucose conc. falls lower because insulin conc. is higher ; this subsumes marking point 1 4 (later) glucose rises higher because insulin conc. is lower ; this subsumes marking point 1 5 use of figures ; e.g. one glucose conc. for inhaled and one for injected at one time or one glucose conc. linked to an insulin conc. at one time (either inhaled or injected) [3 max]
(iii) advantages: 1 faster response time ; 2 less chance of, infection / contamination ; 3 good for people with needle phobia ; max 1 disadvantages : 4 could cause larger swings in blood glucose concentration ; 5 may need to taken more often / not long lasting ; 6 possible variability of dose / AW ; max 1 [2 max]
[Total:15]
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Page 8 Mark Scheme: Teachers’ version Syllabus Paper
oxygen availability low (when soil is flooded) ; plants carry out anaerobic respiration ; ethanol produced ; roots can continue to respire ; [2 max]
(b) (i) (store of) nutrients ; A named nutrient ignore food / water / fibre for, germination / growth of embryo ; [2]
(ii) protein in aleurone layer ; which is removed in white rice ; ora [2]
(iii) endosperm makes up a greater proportion of the total mass in white rice ; or brown rice has more, lipid / fibre / protein, than white rice so less carbohydrates per gram ; [1 max]
(iv) 1 cheap source of food ; 2 high, energy value / fibre content ; 3 high in carbohydrate ; 4 contain wide range of nutrients or three named nutrients ; 5 cereal grains store well ; 6 because they contain very little water ; [2 max]
[Total: 9]
6 (a) variation / different form, of a gene ; [1]
(b) marks for reasons only HbA HbA
low – susceptible to / die from, malaria ; HbA HbS high – no (full blown) SCA / have SC trait ; not, susceptible to / likely to die from, malaria ; HbS HbS low – susceptible to / die from, SCA ; [4]
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Page 9 Mark Scheme: Teachers’ version Syllabus Paper
USA malaria not selection pressure ; HbS no advantage ; due to outbreeding ; genetic testing can lead to termination of pregnancy or testing / counselling, leads to not having children ; [2 max]
[Total: 7]
7 (a) 1 2 3 4
apical bud is source of auxin ; auxin inhibits growth of side shoot ; remove bud and auxin conc falls ; this allows cell, division / elongation, to take place (in side shoots) ; [3 max]
(b) 267 ;; accept suitable working for one mark e.g. 110 – 30 (× 100) 30 or accept 266.7 for one mark [2]
(c) D1 E2 E3 D4 E5 D6
days 2 to 8 no increase in length with paste plus auxin (compared to control) ; auxin moves from paste into plants ; inhibits growth ; days 8 to 13 increase in length occurs (with paste and auxin) ; less auxin left ; supportive figs ; e.g. two blue points on two days plus units or one red and one blue point on same day plus units must have at least one D (description) and one E (explanation) to score 3 marks [3 max]
[Total: 8]
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Page 10 Mark Scheme: Teachers’ version Syllabus Paper
absorb light ; A harvest light / trap light R collect light pass energy to, primary pigment / chlorophyll / reaction centre ; [2 max]
(b) 1 2 3 4 5 6
cyclic photophosphorylation electron emitted returns to, PSI / same photosystem or same chlorophyll molecule ; non-cyclic photophosphorylation electron emitted from PSII absorbed by PSI ; reduced NADP produced ; photolysis occurs ; A splitting of water (photolysis) only involves PSII ; oxygen produced 3 max accept ora for cyclic for marking points 3, 4 and 6 mark to max 3 if cyclic and non-cyclic are described the wrong way round [4 max]
(c) (i) some other factor becomes limiting / temperature no longer limiting ; CO2 / light intensity ; [2]
(ii) line falls towards 70oC ; [1]
(iii) rate of photosynthesis falls enzyme / rubisco, denatured / AW ; substrates not able to fit active site / AW ; [2]
(d) adaptation how the adaptation helps photosynthesis
idea of lipid > protein > carbohydrate / AW ; A lipid has more energy than either protein or carbohydrate comparative figures ; e.g. 39.4, 17.0 and 15.8 accept any two kJ g 1 / per unit mass ; more hydrogen atoms in molecule, more energy ; lipid have more, hydrogen atoms / C-H bonds ; (most) energy comes from oxidation of hydrogen to water ; using reduced, NAD / FAD ; in ETC ; detail of ETC ; ATP production
[6 max]
[Total: 15]
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UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS
GCE Advanced Subsidiary Level and GCE Advanced Level
MARK SCHEME for the October/November 2010 question paper
for the guidance of teachers
9700 BIOLOGY
9700/43 Paper 4 (A2 Structured Questions), maximum raw mark 100
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 must be read in conjunction with the question papers and the report on the examination.
• CIE will not enter into discussions or correspondence in connection with these mark schemes. CIE is publishing the mark schemes for the October/November 2010 question papers for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses.
www.maxpapers.com
Page 2 Mark Scheme: Teachers’ version Syllabus Paper
Mark scheme abbreviations: ; separates marking points / alternative answers for the same point R reject A accept (for answers correctly cued by the question or guidance on the mark scheme) AW alternative wording (where responses may vary more than usual) underline actual word given must be used by the candidate (grammatical variants excepted) max indicates the maximum number of marks that can be given ora or reverse argument
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Page 3 Mark Scheme: Teachers’ version Syllabus Paper
pollution ; environment / habitat, change qualified ; e.g. increase in water temperature / change in water pH overfishing ; loss of food / more competition for food ; direct human interference qualified ; e.g. pleasure boats [3 max]
(b) variety of / different / total number of, species ;
genetic diversity of species / AW ; [2]
(c) 1 2 3 4 5 6 7
any three from tourism / leisure ; economic benefits ; food for humans ; ref. resource / species, may have use in future / AW ; maintains, food webs / food chains ; A description nutrient cycling ; maintains, (large) gene pool / genetic variation ; [3 max]
[Total: 8]
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Page 4 Mark Scheme: Teachers’ version Syllabus Paper
ref. differentiation / specialisation ; ref. Sertoli cell ; forms flagellum ; A tail detail (of flagellum) ; e.g. microtubules acrosome ; detail (of acrosome) ; e.g. contains enzymes / modified lysosome many mitochondria ; [4 max]
(b) 1 2 3 4
accept normal or healthy for undamaged accept abnormal or unhealthy for damaged undamaged sperm move into lower chamber or damaged sperm stay in upper chamber ; undamaged sperm have negatively charged (proteins) or damaged sperm lack negatively charged (protein) ; undamaged sperm are, attracted to positive plate / repelled by negative plate ; ora for damaged sperm idea that undamaged sperm which have, moved / matured, slowly (in epididymis) ; ora for damaged sperm [3 max]
[Total: 7]
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Page 5 Mark Scheme: Teachers’ version Syllabus Paper
(ii) 1 identical (antibodies) or produced by cloning ; 2 variable regions / antigen binding sites, all identical or (antibodies) are specific to one antigen ; [2]
(iii) Mark text first 1 (four) polypeptides ; plural 2 two heavy and two light chains ; A long and short 3 ref. disulphide, bridges / bonds ; 4 ref. variable regions / binding sites ; [3 max]
(b) (i) 1 HAT cannot be metabolised / AW ; 2 HAT inhibits mutant myeloma cells / AW ; [2]
(ii) 1 mouse spleen cells can metabolise HAT / AW ; 2 because they have suitable enzyme ; [2]
(iii) 1 so that only fused cells survive or unfused myeloma cells die ; 2 identifies, cells to be cloned / fused cells ; [2]
(c) 1 2 3 4 5 6
can be done at home / easy to use / non-invasive ; cheap ; result produced quickly ; result likely to be accurate ; can be done early in pregnancy ; safe to use ; [4 max]
[Total: 16]
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Page 6 Mark Scheme: Teachers’ version Syllabus Paper
water lost by, evaporation / transpiration ; no water uptake (by roots) ; [2]
(b) (i) 1 as water potential increases, oxygen uptake increases ; must be stated 2 levels off (at 5 kPa / at 225 au) ; 3 figures ; two water potential plus two oxygen uptake figures plus kPa [2 max]
(ii) 1 succinate converted to oxaloacetate ; 2 dehydrogenation / oxidation ; 3 NAD, is reduced / accepts hydrogen ; 4 (hydrogens move to) ETC ; 5 hydrogen splits into protons and electrons ; 6 electrons pass along ETC ; 7 ADP + Pi ATP ; 8 oxygen, receives protons and electrons / is final electron acceptor, to
form water ; [4 max]
(c) (i) 1 water leaves mitochondrion ; A other named organelle 2 by osmosis / down water potential gradient ; 3 idea mechanical disruption to membranes ; 4 membranes made of phospholipid (bilayer) ; 5 hydrophilic heads / glycoproteins / glycolipids, form fewer hydrogen
(ii) 1 inner membrane (of mitochondrion) / cristae, site of ETC ; 2 fewer carriers held in position ; 3 fewer electrons pass along ETC ; 4 less ATP produced / less energy released ; 5 less oxygen required to act as electron acceptor ; 6 protons can move freely through the damaged inner membrane ; 7 proton gradient not formed ; accept ora for less damaged membranes for marking points 2–7 [3 max]
(d) 1 2 3 4
extensive / deep, roots ; leaves have small surface area ; leaves, are curled / are waxy / have bulliform cells / have hinged cells ; reduced stomata numbers / stomata in pits ; [2 max]
[Total: 16]
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Page 8 Mark Scheme: Teachers’ version Syllabus Paper
AAV2.5T infects more cells than AAV / AW ; both increase until 20 days ; AAV2.5T falls after 20 days but AAV remains steady ; figures ; two intensities on a single day [2 max]
(b) 1 2
infected cells fluoresce (when luciferin added) ; able to identify infected cells ; [2]
(c) 1 2 3 4 5 6 7
correct form of (CFTR) protein made ; delivered to / inserted into, membrane ; acts as chloride channel ; chloride ions leave cell ; water leaves cell ; normal / less viscous, mucus formed ; give credit to mention of one symptom reversed ; e.g. no blockage of airways / less chance of infections [4 max]
[Total: 8]
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Page 9 Mark Scheme: Teachers’ version Syllabus Paper
drought reduced available food or fewer small seeds produced ; finches with larger beaks survived or finches with smaller beaks died ; able to open tough fruits / ora ; able to feed on larger seeds / ora ; tough fruit / size of seed, acted as selection pressure ; [3 max]
(c) directional / evolutionary ; selection pressure acts on one extreme (of range) ; [2]
[Total: 7]
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Page 10 Mark Scheme: Teachers’ version Syllabus Paper
homeostasis / AW ; change in water potential ; detected by (osmo)receptors ; in hypothalamus ; response via effector ; ADH released ; effect on collecting duct ; return to, norm / set point ; [4 max]
(c) 1 2 3 4
blood diverted away from skin ; less sweating ; more water retained in body / high water potential in body ; less water reabsorbed from collecting duct / AW ; [2 max]
[Total: 8]
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Page 11 Mark Scheme: Teachers’ version Syllabus Paper
high rate of photosynthesis at 430–435 nm and 655 nm wavelengths ; idea of (high) absorption of light at these wavelengths ; highest rate, at 430–435 nm ; shorter wavelengths have more energy ; low(er rate) in, middle range / 500–600, of wavelengths ; low light absorption here ; absorbed light used for photosynthesis ; in light-dependent stage ; [4 max]
(b) (i) ATP ; reduced NADP ; [2]
(ii) 1 ATP provides energy ; 2 reduced NADP, is reducing agent / provides hydrogen ; 3 for converting GP to TP ; 4 (ATP used to) regenerate RuBP ; [3 max]
(c) process / photosynthesis, affected by more than one factor ; rate is limited by the factor nearest its minimum value / AW ; [2]
(d) 1 2 3 4 5 6 7
enters leaf through (open) stomata ; by diffusion ; substomatal air space ; many air spaces in spongy mesophyll ; spaces between palisade cells ; dissolves in moisture on cell (walls) ; enters through cell walls ; [4 max]
[Total: 15]
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Page 12 Mark Scheme: Teachers’ version Syllabus Paper
exchange of genetic material / AW ; R genes unqualified
linkage groups broken ;
new combination of alleles ;
independent assortment (of homologous chromosomes) ; R random assortment
at equator ;
(during) metaphase 1 ;
possible mutation ;
random mating ;
random fusion / fertilisation of gametes ; [7 max]
(b) 14
15 16 17 18 19 20 21
22 23 24 25 26
phenotypic variation results from interaction of genotype and environment / VP = VG + VE ;
environment may modify expression of gene(s) ; must be stated e.g. for size / mass / height ; because, food / nutrient / ion, missing or in short supply ; A malnutrition named, food / nutrient / ion, (missing or in short supply) ; environment may, trigger / switch on, gene ; must be stated ref. low temperature and change in animal colour ; ref. high temperature and, curled wing in Drosophila / gender in crocodiles ;
ref. UV light and melanin production ; ref. wavelength of light and, flowering / germination / fruit colour ; other named trigger plus example ; environment effect usually greater on polygenes / ora ; environment may induce mutation affecting phenotype ; [8 max]
[Total: 15]
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Page 13 Mark Scheme: Teachers’ version Syllabus Paper
nucleotide ; adenine + ribose / pentose + three phosphates ; loss of phosphate leads to energy release / hydrolysis releases 30.5 kJ ; ADP + Pi ATP (reversible reaction) ; small packets of energy ; small / water soluble, so can move around cell ; used by cells as immediate energy donor ; link between energy yielding and energy requiring reactions / AW ; high turnover ; two examples of use ; ; e.g. active transport / muscle contraction / Calvin cycle / protein synthesis [8 max]
(b) 12 13 14 15 16 17 18 19 20 21 22 23 24
Pyruvate, cannot enter mitochondrion / remains in the cytoplasm ; becomes, hydrogen acceptor / reduced ; by reduced NAD ; from glycolysis ; converted to lactate ; lactate dehydrogenase ; allows glycolysis to continue ; no, decarboxylation / CO2 removed ; single step ; reversible reaction / converted back to pyruvate ; by oxidation ; ref. oxygen debt ; ethanol produced ; accept ora for marking points 19–23 [7 max]
[Total: 15]
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UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS
GCE Advanced Subsidiary Level and GCE Advanced Level
MARK SCHEME for the October/November 2010 question paper
for the guidance of teachers
9700 BIOLOGY
9700/51 Paper 5 (Planning, Analysis and Evaluation), maximum raw mark 30
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 must be read in conjunction with the question papers and the report on the examination.
• CIE will not enter into discussions or correspondence in connection with these mark schemes. CIE is publishing the mark schemes for the October/November 2010 question papers for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses.
www.maxpapers.com
Page 2 Mark Scheme: Teachers’ version Syllabus Paper
Mark schemes abbreviations: ; separates marking points / alternative answers for the same point R reject A accept (for answers correctly cued by the question, or guidance on the mark scheme) AW alternative wording (where responses vary more than usual) underline actual word given must be used by the candidate (grammatical variants excepted) max indicates the maximum number of marks that can be given
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Page 3 Mark Scheme: Teachers’ version Syllabus Paper
1 (a) (i) light + intensity / exposure; do not allow light unqualified or position in shade / sun [1]
(ii) 8 of: independent variable: 1. ref. to a systematic way of obtaining leaves; dependent variables: 2. ref. to a method of measuring surface area; 3. ref. to how surface area is calculated; 4. ref. to idea of both sides needed to get total surface
area; 5. ref. to a method of measuring mass; 6. ref. to finding dry mass; 7. ref. to a method of measuring internode length either on
the plant or a cut section from a plant; 8. ref. to a method of measuring water loss; 9. ref. method of using the transpiration apparatus; 10. ref. to keeping constant environment when measuring
water loss; (max. 6)
safety: 11. ref. to low risk investigation; reliability 12. ref. to mean values of the whole sample; 13. ref. to method of working out SA : mass ratio; 14. ref. to calculating standard deviation;
ignore any reference to planting seeds / potted plants 1. e.g. 3rd leaf from the apex / different heights / all from
the same height / equal light exposure 2. e.g. draw round each leaf on grid or use transparent
grid over leaf / measure diameter(s) of leaf
3. count squares / use formula πr2
5. e.g. digital balance / scales 6. e.g. sample leaves dried in oven until mass constant 7. by holding against a ruler / use string or cotton to mark
distance measure with ruler 8. e.g. use a potometer / weigh leaf / place leaf inside a
plastic bag (to collect water) 9. measure distance moved by water / weigh at hourly
intervals / weigh bag or leaf after a stated time 11. e.g. ref. heat and suitable precaution if use dry mass /
leaf allergy 12. do not allow ‘mean of three idea’ 14. ignore formula [8]
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Page 4 Mark Scheme: Teachers’ version Syllabus Paper
allow ecf for incorrect figure from subtraction [3]
(ii) total number of measurements –1 for each set of
measurement /
(30 – 1) + (30 – 1) = 58;
allow 2n – 2 / (n – 1) + (n – 1) 60 – 2 = 58 [1]
(iii) ref. (both) calculated / t values are greater than the critical value / 0.2; both results are significant / not due to chance / caused by another factor / light exposure;
if the calculation is omitted from (b)(i) both marks are still available allow ecf from (b)(i) ignore null hypothesis unless explained [2]
(c) (i) ref. to counting the number of eye piece graticule units; ref. to idea of finding the value of an eyepiece unit with a stage micrometer
allow descriptions / ref. to a standard graticule unit value
[2]
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Page 5 Mark Scheme: Teachers’ version Syllabus Paper
(ii) Marks are for conclusions about the adaptations shown by the plants. Do not allow marks for answers that restate the data in table 1.1 3 of: EITHER for shade leaves: 1. thinner cuticle increases light penetration; 2. thinner leaf / shorter palisade cells increases light
penetration (to inner parts of leaf); 3. spongy mesophyll has more chloroplasts to increase
light absorption; 4. cells less densely packed / larger air spaces for better
gas diffusion; 5. larger surface area to absorb limited light / enables
more photosynthesis with less light availability; OR for sun / exposed leaves: 1. thicker cuticle limits water loss; 2. (large / long palisade cells) contain more chloroplasts to
absorb maximum light; 3. fewer chloroplasts in spongy mesophyll as little light
penetrates / palisade is light saturated; 4. densely packed cells / smaller air spaces reduce water
loss; 5. smaller surface area reduces water loss;
Look for the understanding that shade leaves have adaptations that maximise photosynthesis and sun leaves have adaptations to minimise water loss. allow mix and match for sun and shade leaves but take care not to give the same mark twice. candidates should make it clear which type of leaf they are referring to. ignore anything related to growth ignore any references to internodes ignore any references to stomata
[3]
[Total: 20]
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Page 6 Mark Scheme: Teachers’ version Syllabus Paper
2 (a) (i) 2 of: length of organism; time for adjustment (to temperature); time of measurement;
do not allow size
[2]
(ii) 1 of: activity / age / sex / mass of organism; source / type / pH / volume of water; oxygen supply;
do not allow microscope lamp / light
[1]
(iii) 1 of: counting high rates is error prone; changes in temperature; activity / stress affect heart rate;
allow oxygen content if not in (ii) e.g. light from microscope / cooling
[1]
(iv) idea of sufficient measurements for reliability / to remove anomalous results;
do not allow accurate ignore reduce error / fair test [1]
(b) (i) allows for different starting points between individuals / can see the changes more clearly;
looking for the idea that ‘it is easier to see what is happening / make comparisons’ [1]
(ii) C 25 at rate
C 25 and C 30 at rate in difference / C 25 at rate C 30 at rate
°
°°°−°
× 100;
allow correct use of any figures from the table
e.g. 132
132165× 100
[1]
(iii) decrease (by at least 50%) / falls to a very low value / may stop;
[1]
(c) support: 5 °C – 15 °C / 15 °C – 25 °C / 10 °C – 20 °C (as rate approx. doubles with10 °C increase); does not support: 20 °C – 30 °C increases but does not double / 25 °C – 35 °C decreases / above 30 °C rapidly decreases with temperature increase;
allow ‘below 30 °C’ / ‘up to 25 °C’ allow above 30 °C – 35 °C rapidly decreases with temperature increase;
[2]
[Total: 10]
www.maxpapers.com
UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS
GCE Advanced Subsidiary Level and GCE Advanced Level
MARK SCHEME for the October/November 2010 question paper
for the guidance of teachers
9700 BIOLOGY
9700/52 Paper 5 (Planning, Analysis and Evaluation), maximum raw mark 30
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 must be read in conjunction with the question papers and the report on the examination.
• CIE will not enter into discussions or correspondence in connection with these mark schemes. CIE is publishing the mark schemes for the October/November 2010 question papers for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses.
www.maxpapers.com
Page 2 Mark Scheme: Teachers’ version Syllabus Paper
Mark schemes abbreviations: ; separates marking points / alternative answers for the same point R reject A accept (for answers correctly cued by the question, or guidance on the mark scheme) AW alternative wording (where responses vary more than usual) underline actual word given must be used by the candidate (grammatical variants excepted) max indicates the maximum number of marks that can be given
www.maxpapers.com
Page 3 Mark Scheme: Teachers’ version Syllabus Paper
1 (a) (i) light + intensity / exposure; do not allow light unqualified or position in shade / sun [1]
(ii) 8 of: independent variable: 1. ref. to a systematic way of obtaining leaves; dependent variables: 2. ref. to a method of measuring surface area; 3. ref. to how surface area is calculated; 4. ref. to idea of both sides needed to get total surface
area; 5. ref. to a method of measuring mass; 6. ref. to finding dry mass; 7. ref. to a method of measuring internode length either on
the plant or a cut section from a plant; 8. ref. to a method of measuring water loss; 9. ref. method of using the transpiration apparatus; 10. ref. to keeping constant environment when measuring
water loss; (max. 6)
safety: 11. ref. to low risk investigation; reliability 12. ref. to mean values of the whole sample; 13. ref. to method of working out SA : mass ratio; 14. ref. to calculating standard deviation;
ignore any reference to planting seeds / potted plants 1. e.g. 3rd leaf from the apex / different heights / all from
the same height / equal light exposure 2. e.g. draw round each leaf on grid or use transparent
grid over leaf / measure diameter(s) of leaf
3. count squares / use formula πr2
5. e.g. digital balance / scales 6. e.g. sample leaves dried in oven until mass constant 7. by holding against a ruler / use string or cotton to mark
distance measure with ruler 8. e.g. use a potometer / weigh leaf / place leaf inside a
plastic bag (to collect water) 9. measure distance moved by water / weigh at hourly
intervals / weigh bag or leaf after a stated time 11. e.g. ref. heat and suitable precaution if use dry mass /
leaf allergy 12. do not allow ‘mean of three idea’ 14. ignore formula [8]
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Page 4 Mark Scheme: Teachers’ version Syllabus Paper
allow ecf for incorrect figure from subtraction [3]
(ii) total number of measurements –1 for each set of
measurement /
(30 – 1) + (30 – 1) = 58;
allow 2n – 2 / (n – 1) + (n – 1) 60 – 2 = 58 [1]
(iii) ref. (both) calculated / t values are greater than the critical value / 0.2; both results are significant / not due to chance / caused by another factor / light exposure;
if the calculation is omitted from (b)(i) both marks are still available allow ecf from (b)(i) ignore null hypothesis unless explained [2]
(c) (i) ref. to counting the number of eye piece graticule units; ref. to idea of finding the value of an eyepiece unit with a stage micrometer
allow descriptions / ref. to a standard graticule unit value
[2]
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Page 5 Mark Scheme: Teachers’ version Syllabus Paper
(ii) Marks are for conclusions about the adaptations shown by the plants. Do not allow marks for answers that restate the data in table 1.1 3 of: EITHER for shade leaves: 1. thinner cuticle increases light penetration; 2. thinner leaf / shorter palisade cells increases light
penetration (to inner parts of leaf); 3. spongy mesophyll has more chloroplasts to increase
light absorption; 4. cells less densely packed / larger air spaces for better
gas diffusion; 5. larger surface area to absorb limited light / enables
more photosynthesis with less light availability; OR for sun / exposed leaves: 1. thicker cuticle limits water loss; 2. (large / long palisade cells) contain more chloroplasts to
absorb maximum light; 3. fewer chloroplasts in spongy mesophyll as little light
penetrates / palisade is light saturated; 4. densely packed cells / smaller air spaces reduce water
loss; 5. smaller surface area reduces water loss;
Look for the understanding that shade leaves have adaptations that maximise photosynthesis and sun leaves have adaptations to minimise water loss. allow mix and match for sun and shade leaves but take care not to give the same mark twice. candidates should make it clear which type of leaf they are referring to. ignore anything related to growth ignore any references to internodes ignore any references to stomata
[3]
[Total: 20]
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Page 6 Mark Scheme: Teachers’ version Syllabus Paper
2 (a) (i) 2 of: length of organism; time for adjustment (to temperature); time of measurement;
do not allow size
[2]
(ii) 1 of: activity / age / sex / mass of organism; source / type / pH / volume of water; oxygen supply;
do not allow microscope lamp / light
[1]
(iii) 1 of: counting high rates is error prone; changes in temperature; activity / stress affect heart rate;
allow oxygen content if not in (ii) e.g. light from microscope / cooling
[1]
(iv) idea of sufficient measurements for reliability / to remove anomalous results;
do not allow accurate ignore reduce error / fair test [1]
(b) (i) allows for different starting points between individuals / can see the changes more clearly;
looking for the idea that ‘it is easier to see what is happening / make comparisons’ [1]
(ii) C 25 at rate
C 25 and C 30 at rate in difference / C 25 at rate C 30 at rate
°
°°°−°
× 100;
allow correct use of any figures from the table
e.g. 132
132165× 100
[1]
(iii) decrease (by at least 50%) / falls to a very low value / may stop;
[1]
(c) support: 5 °C – 15 °C / 15 °C – 25 °C / 10 °C – 20 °C (as rate approx. doubles with10 °C increase); does not support: 20 °C – 30 °C increases but does not double / 25 °C – 35 °C decreases / above 30 °C rapidly decreases with temperature increase;
allow ‘below 30 °C’ / ‘up to 25 °C’ allow above 30 °C – 35 °C rapidly decreases with temperature increase;
[2]
[Total: 10]
www.maxpapers.com
UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS
GCE Advanced Subsidiary Level and GCE Advanced Level
MARK SCHEME for the October/November 2010 question paper
for the guidance of teachers
9700 BIOLOGY
9700/53 Paper 5 (Planning, Analysis and Evaluation), maximum raw mark 30
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 must be read in conjunction with the question papers and the report on the examination.
• CIE will not enter into discussions or correspondence in connection with these mark schemes. CIE is publishing the mark schemes for the October/November 2010 question papers for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses.
www.maxpapers.com
Page 2 Mark Scheme: Teachers’ version Syllabus Paper
Mark schemes abbreviations: ; separates marking points / alternative answers for the same point R reject A accept (for answers correctly cued by the question, or guidance on the mark scheme) AW alternative wording (where responses vary more than usual) underline actual word given must be used by candidate (grammatical variants excepted) max indicates the maximum number of marks that can be given ora or reverse argument
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Page 3 Mark Scheme: Teachers’ version Syllabus Paper
1 (a) (i) time taken for blue colour to become colourless / AW ; A time to change colour / AW [1]
(ii) to prevent oxygen entering / prevent re-oxidation of methylene blue ;
A the idea of it allows the methylene blue to work as a hydrogen acceptor Ignore air, carbon dioxide, gas exchange [1]
(iii) 7 of: independent variable: 1. ref. to water-baths at different temperatures ; 2. at least 5 different temperatures ; 3. ref. to suitable range ; 4. ref. to retesting within the approximate optimum zone ; dependent variable 5. ref. to fastest time until blue disappears is optimum ; 6. ref. to colour comparison / control without methylene blue
added ; control variables 7. ref. to standard volume of yeast / suspension (in tube) ; 8. ref. to adding standard volume methylene blue ; procedure 9. ref. inverting / stirring (to mix indicator and yeast) ; 10. ref. to repeats / replicates – min 3 and mean value to remove anomalies ; safety: 11. ref. to a low risk experiment ;
1. allow other suitable means of maintaining
constant temperature 3. e.g. 0
°C – 70 °C. Any range in this but at least one below 30 °C and one above
5. A ...becomes colourless 7. R amount unqualified A known mass / weight for (dried) yeast
provided some water added Ignore glucose 8. R amount /drop(s) A inject known volume of methylene blue
through the oil layer 11. A ref. to possible toxicity of methylene blue /
allergy to yeast / hot water and tongs, etc. [7]
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Page 4 Mark Scheme: Teachers’ version Syllabus Paper
(b) 3 of: 1. (yeast) can use / respire/ metabolise fructose, glucose
sucrose and maltose ; 2. (yeast) has enzyme(s) to use above sugar(s) ; ora 3. (yeast) uses / takes up, fructose preferentially, as highest rate
/ AW ; 4. sucrose has a high rate as a source of fructose / AW ; 5. maltose / sucrose are larger so take longer to take up / AW ; 6. disaccharides / named disaccharide have to be hydrolysed / AW ;
1. little / no, use with galactose and lactose 3. A refs. to respiration as idea of uses
[3]
(c) (i) 12
4 ;
= 1.16 / 1.15; = 1 cell;
A 4 / 3
A 1.2 (1.33 /1.3 if use 4 / 3) allow ecf if any value other than √12 used [3]
(ii) ref. to spread of data from the mean value / AW; ref. to larger value the less reliable the results / AW ;
A with reference to data in question R if accurate mentioned as well as reliable [2]
(iii) axes correct and labelled ; correctly plotted bar chart ; error bars correct using SM values; (plus and minus 2 and 1)
y – mean, no. cells per mm3 / population size per mm3 x – each block labelled with correct sugar / key R histogram / line graph A sd values (plus and minus 8 and 4) [3]
(iv) 1 of: yes: difference in mean number of cells / AW ; yes: standard error does not give overlap in populations; no: some raw data overlaps / standard deviation overlaps ; inconclusive: as no statistics tests carried out ;
reason must be consistent with their choice ignore qualifications like large / significant A ‘no’ if no statistics done [1]
[Total: 21]
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Page 5 Mark Scheme: Teachers’ version Syllabus Paper
A cigarette. Ignore ‘amount’ etc. A description of reaction time [2]
(ii) 2 × 2 of: memory test time (for exposure to letters) ; constant time for which stimuli shown / 250 ms ; time between stimuli and test ; constant time / 1000 ms ; non smoking time prior to start of test ; constant time / 12 hours ; nicotine content of cigarette for each test; fixed mass in each cigarette; test group / AW ; same group used ; number of tests / single letters tested ; 50 / same ; difficulty of memory test ; varying the number of letters used (to randomise the test) ;
A amount / figures quoted 0.05mg / 1.1mg R ‘all regular smokers’
[4]
(b) 3 of: support: reaction time decreases with nicotine / higher nicotine (1.1mg) greatest decrease ; 1.1 mg (nicotine) increases number of letters correct / improves accuracy ; against: 0.05 mg (nicotine) decreases accuracy / decreases number of letters correct / small differences in number of letters correct ; ref. to error bar overlap in, accuracy data / reaction time between no smoking and 0.05 mg ;