8040 8042 9040 9042 GCE Biology msc 20060803€¦ · · 2016-04-07Edexcel GCE Biology / Biology (Human) ... Unit 3 6103/02* 6103/03 ... Summer 2006 6101 Unit 1 Mark Scheme Page

Summer 2006

GCE Edexcel GCE

Biology (9040)

Biology (Human) (9042)

Mark Schemes

Edex

cel G

CE

Biol

ogy

/ Bi

olog

y (H

uman

) (9

040/

9042

)

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Summer 2006

Publications Code UA017732

All the material in this publication is copyright © Edexcel Ltd 2006

www.egyptigstudentroom.com

i

Contents

General Introduction p ii Unit Codes and Unit Titles p iii General Information p iv

Mark Schemes

Unit 1 6101 Molecules and cells p 1

Unit 2B Unit 2H

6102 6112

Exchange, transport and reproduction Exchange, transport and reproduction in humans

p 10 p 18

Unit 3 6103/02* 6103/03

Written alternative to coursework* Energy and the environment

p 26 P 30

Unit 4 Core material Option A Option B Option C

Respiration and coordination Microbiology and biotechnology Food science Human health and fitness

p 35 p 40 p 44 p 48

Unit 5B Unit 5H

6105 6115

Genetics, evolution and biodiversity Genetics, human evolution and biodiversity

p 52 p 61

Unit 6 6106/02 6106/03

Written alternative to coursework Synoptic Paper

p 70 p 74

* 6103/02 W1 (written alternative to coursework) is only available to International centres


ii

GENERAL INTRODUCTION Mark schemes are prepared by the Principal Examiners and revised, together with the relevant questions, by a panel of senior examiners and subject teachers. The schemes are further amended at the Standardisation meetings attended by all examiners. The Standardisation meeting ensures as far as possible that the mark scheme covers the candidates' actual responses to questions and that every examiner understands and applies it in the same way. The schemes in this document are the final mark schemes used by the examiners in this examination and include the amendments made at the meeting. They do not include any details of the discussions that took place in the meeting, nor do they include all of the possible alternative answers or equivalent statements that were considered to be worthy of credit. It is emphasised that these mark schemes are working documents that apply to these papers in this examination. Every effort is made to ensure a consistent approach to marking from one examination to another but each marking point has to be judged in the context of the candidates' responses and in relation to the other questions in the paper. It should not be assumed that future mark schemes will adopt exactly the same marking points as this one. Edexcel cannot under any circumstances discuss or comment informally on the marking of individual scripts. Any enquiries about the marks awarded to individual candidates can be dealt with only through the official Enquiry about Results procedure.


iii

Unit Codes and Unit Titles These Mark Schemes cover the units offered in this examination for Advanced Subsidiary Biology and Biology (Human) (8040 and 8042) and Advanced Biology and Biology (Human) (9040 and 9042). The units available in this examination series for the complete qualifications are listed in the table below. Level Unit Biology Biology (Human)

1 6101 Molecules and cells 6101

2 6102 Exchange, transport and reproduction

Exchange, transport and reproduction in humans 6112

AS

3 6103 Energy and the environment and Practical Assessment 6103

4 6104 Respiration and coordination and Options 6104

5 6105 Genetics, evolution and biodiversity

Genetics, human evolution and biodiversity 6115

A2

6 6106 Synoptic and Practical Assessment 6106

Cashing in The following tables show the units that must be taken in order to obtain an award for AS or Advanced GCE Biology, or for AS or Advanced GCE Biology (Human). Advanced Subsidiary Level Unit 8040 Biology 8042 Biology (Human)

AS 1 2 3

6101 6102 6103

6101 6112 6103

Advanced GCE Level Unit 9040 Biology 9042 Biology (Human)

AS 1 2 3

6101 6102 6103

6101 6112 6103

A2 4 5 6

6104 6105* 6106*

6104 6115* 6106*

* Only available in Summer examination series.


iv

GENERAL INFORMATION The following symbols are used in the mark schemes for all questions:

Symbol Meaning of symbol

; semi colon Indicates the end of a marking point

eq Indicates that credit should be given for other correct alternatives to a word or statement, as discussed in the Standardisation meeting

/ oblique Words or phrases separated by an oblique are alternatives to each other

{} curly brackets Indicate the beginning and end of a list of alternatives (separated by obliques) where necessary to avoid confusion

() round brackets Words inside round brackets are to aid understanding of the marking point but are not required to award the point

[] square brackets Words inside square brackets are instructions or guidance for examiners

[CE] or [TE] Consecutive error / transferred error Crossed out work If a candidate has crossed out an answer and written new text, the crossed out work can be ignored. If the candidate has crossed out work but written no new text, the crossed out work for that question or part question should be marked, as far as it is possible to do so. Spelling and clarity In general, an error made in an early part of a question is penalised when it occurs but not subsequently. The candidate is penalised once only and can gain credit in later parts of the question by correct reasoning from the earlier incorrect answer. No marks are awarded specifically for quality of language in the written papers, except for the essays in the synoptic paper. Use of English is however taken into account as follows: • the spelling of technical terms must be sufficiently correct for the answer to be

unambiguous e.g. for amylase, ‘ammalase’ is acceptable whereas ‘amylose’ is not e.g. for glycogen, ‘glicojen’ is acceptable whereas ‘glucagen’ is not e.g. for ileum, ‘illeum’ is acceptable whereas ‘ilium’ is not e.g. for mitosis, ‘mytosis’ is acceptable whereas ‘meitosis’ is not • candidates must make their meaning clear to the examiner to gain the mark. • a correct statement that is contradicted by an incorrect statement in the same part

of an answer gains no mark – irrelevant material should be ignored.


Summer 2006 6101 Unit 1 Mark Scheme

Page 1 6101 June 2006

Unit 1 (6101) Question 1 Maximum marks

Statement DNA mRNA

Double stranded

Adenine and uracil

Pentose sugar

Phosphodiester

[Any 2 correct = 1 mark]

Total 4 marks



Page 2 6101 June 2006

Question 2 Maximum marks 1 Energy store ; 2 Heat insulation / protection / buoyancy / energy store ; 3 Heat insulation / protection / buoyancy /energy store ; 4 Waterproof/eq ;

Total 4 marks



Page 3 6101 June 2006

Question 3 Maximum marks Diagram mark (cell wall, no nucleus, slime capsule, pili or membrane-bound

organelles, genetic material or flagellum) ; Any 3 labelled structures: Cell wall ; Invaginations / mesosome ; Flagellum ; Bacterial chromosome / circular DNA ; Plasmid ; 70s ribosomes

Total 4 marks



Page 4 6101 June 2006

Question 4 Maximum marks (a) A Granum / (stack of) thylakoids ; B Stroma ; C Starch grain ;

3 marks (b) Correct width measured (mm / cm) ; Width / 5000 ; Correct conversion into µm ;

3 marks (c) Palisade (mesophyll cells) ; Spongy (mesophyll cell) ; Guard (cells) ; [“Mesophyll” unqualified = 1 mark]

2 mark

Total 8 marks



Page 5 6101 June 2006

Question 5 Maximum marks (a) Peptide bond drawn correctly ; Rest of both amino acids drawn correctly ;

2 marks (b) (i) Reference to α-helix / β-pleated sheet ; Reference to hydrogen bonds ;

2 marks (ii) 1. The primary structure is the same length at both temperatures ; 2. The secondary structure is shorter at 25 °C ; 3. Length decreases from primary to secondary at both temperatures ; 4. Correct manipulation of figures ;

2 marks (iii) 1. Reference to increase in kinetic energy at (55 °C) ; 2. (More) vibrations within molecule ; 3. Therefore hydrogen bonds (holding α-helix / β-pleated sheet together) break/eq; 4. (Molecule) starts to unwind ;

2 marks

Total 8 marks



Page 6 6101 June 2006

Question 6 Maximum marks (a) 1. Tendency of water molecules to move/ to be lost / to be gained ; 2. Determined by the {solute potential / concentration of solute / eq} ; 3. Reference to units ;

2 marks (b) (i) (Increase in mass) due to uptake of water / eq ; Idea of {water potential of potato is less than (0.2 mol dm-3) sucrose solution /

lower water concentration in potato cell than in sucrose solution / eq} ; 2 marks

(ii) 0.74 ± 0.01 (mol dm-3) ;

1 mark (iii) No difference in water potentials / eq ; So no net movement of water molecules / eq ;

2 marks (c) 1. Reference to cellulose ; 2. Reference to hydrogen bonds (between chains) ; 3. Reference to microfibrils ; 4. Reference to criss-cross arrangement (of microfibrils)/ eq ; 5. Embedded in matrix/ Reference to {pectin / hemicellulose} ;

3 marks

Total 10 marks



Page 7 6101 June 2006

Question 7 Maximum marks (a) (i) 4 ; (ii) 4 ;

2 marks (b) 1. Idea of using a short length of root tip ; 2. Ref. to acidification ; 3. Add {acetic orcein / acetocarmine / Feulgens stain / Schiffs reagent / Toluidine

Blue / Lactoproprionic Acid} ; 4. Warm / heat ; 5. Break open tip (with mounted needle / eq) ; 6. Mount/ eq in {stain / acid / water} ; 7. (Gently) squash under coverslip or slide ; 8. Warm slide (to intensify staining) ;

5 marks (c) (i) Metaphase /prophase ;

1 mark (ii) Spindle is made during prophase ; (If there is no spindle) {there is nothing for the chromosomes to attach to (in

metaphase)} / {chromatids cannot be pulled apart (in anaphase)} ;

2 marks

Total 13 marks



Page 8 6101 June 2006

Question 8 Maximum marks (a) (i) 1. (Due to) inhibitor/eq having similar shape/eq to substrate ; 2. {Attach to / block} active site ; 3. Therefore substrate cannot bind / eq. ; 4. Reference to competition ; 5. Reference to reversible and irreversible (inhibition) ;

6 Reduces {rate of reaction / enzyme activity} / stops the reaction (in correct context);

3 marks (ii) All molecules {have COO- / same charge/ same groups} at each end / eq /similar

chemical structure ;

1 mark (iii) 1. Not similar shape to substrate / eq ; 2. Does not compete with substrate ; 3. Binds to {a different site / allosteric site / eq} ; 4. Changing the shape of the active site ;

2 marks



Page 9 6101 June 2006

Question 8 continued Maximum marks (b) (i) Increases as substrate concentration increases up to 29/30 mg cm -3; Linear between 0 -15 mg cm-3 or 15 -25 mg cm-3 ; Remains {constant / eq} after 29/30 mg cm-3 ;

2 marks (ii) All active sites are occupied / eq ; At any given time / eq ; Enzyme concentration is limiting / substrate concentration is not limiting / V max

;

2 mark (iii) Rate of reaction is slower ; Reaches a lower maximum rate of reaction ; Correct manipulation of data ;

2 marks

Total 12 marks


Summer 2006 6102 Unit 2B Mark Scheme

Page 10 6102 June 2006

Unit 2B (6102) Question 1 Maximum mark External ; Contract ; Increase / eq ; Decreases / eq ;

Total 4 marks



Page 11 6102 June 2006

Question 2 Maximum mark (a) Cell A Neutrophil / polymorph /granulocyte ; Cell B Lymphocyte / agranulocyte ;

2 marks (b) Produces antibodies ; In presence of antigens / attach to antigens/ Correct reference to function of

antibody (e.g. clumping of bacteria)/ reference to the formation of memory cells;

2 marks (c) 1 Contain haemoglobin which {combines/eq} with carbon dioxide ; 2 To form carbaminohaemoglobin/eq ; 3 Presence of carbonic anhydrase ; 4 Formation of {carbonic acid / correct equation} ; 5 Formation of {hydrogencarbonate / correct equation} ;

3 marks

Total 7 marks



Page 12 6102 June 2006

Question 3 Maximum mark (a) Reference to {blood pressure / hydrostatic pressure} ; Forces out {water (and solutes)/plasma minus the protein} ; Of capillaries ; Reference to {basement membrane / pores} ;

3 marks (b) (i) Protein (molecules) are large / eq ; Cannot pass through {cell membranes / capillary (walls) / eq} ;

2 marks (ii) 1. Sodium ions are small ; 2. Membrane is permeable to sodium ions / sodium ions can {diffuse / pass through}

{cell membrane / capillary (walls) / pores} / eq ; 3. No net diffusion / movement ;

2 marks

Total 7 marks



Page 13 6102 June 2006

Question 4 Maximum mark (a) (i) Microvillus/ microvilli ;

1 mark (ii) Reference to membrane-bound enzymes/eq ; Named example of enzyme (sucrase, lactase, maltase); Reference to correct substrates and products / enzymes that convert

disaccharides to monosaccharides / eq ; 2 marks

(b) 1. Membrane of {epithelial cell / microvillus} ; 2. Has carrier proteins ; 3. Reference to sodium co-transport ; 4. Reference to active transport ; 5. Reference to facilitated diffusion ; 6. Diffusion (of glucose) into {blood / capillary} from epithelial cell ; 7. Reference to blood flow maintains {diffusion / concentration} gradient ;

4 marks (c) Bread contains starch ; White bread digested more quickly than wholemeal / eq ; Jam contains {sugars / glucose} ; Which are absorbed directly/eq ;

3 marks

Total 10 marks



Page 14 6102 June 2006

Question 5 Maximum mark (a) Number of stomata = 13 ; [check with final picture] ÷ 0.102 ; Answer = 127 (per mm2) ;

3 marks (b) (i) It increases / eq ; By 0.35 mol dm-3 / eq ;

2 marks (ii) (Increase in potassium concentration) reduces solute potential / eq ; Water moves into cells ; Down water potential gradient / by osmosis ; Results in an increase in turgor (of guard cells) / describe change in shape of

guard cells ; 3 marks

Total 8 marks



Page 15 6102 June 2006

Question 6 Maximum mark (a) Pollen tube ;

1 mark (b) One male nucleus fuses with egg cell / eq ; Forms zygote ; Which is {diploid / eq} ; One male nucleus fuses with {polar nuclei / fusion nucleus} ; Forms endosperm ; Which is {triploid / eq} ;

4 marks (c) (i) 21 to 22 (%) ;

1 mark (ii) {Rises / 21- 24% figs. Given} from 10 to 15 % ; Reaches {a peak /eq} at 15 % ; Decreases from 15 to 25 % ;

2 marks

Total 8 marks


Page 16 6102 June 2006

Question 7 Maximum mark (a) Stage Prophase I / metaphase I / diplotene /diakinesis; Reason Chromosomes paired / bivalents present / synopsis ; Reference to {chiasmata formation / crossing over} ;

3 marks (b) (i) 180 ; (ii) 360 ;

2 marks (c) Halves the number of chromosomes /eq ; Reference to genetic variability / eq ; Diploid number restored at fertilisation / eq ;

2 marks

Total 7 marks


Page 17 6102 June 2006

Question 8 Maximum mark (a) Corpus luteum / yellow body ;

1 mark (b) {Maintenance / eq} of {endometrium / uterus lining} ; Inhibits secretion of {FSH / LH} ; Inhibits secretion of {FSH / LH} releasing hormone ; Inhibits ovulation ; Inhibits prolactin secretion ; Inhibits contraction of uterus ;

2 marks (c) Line drawn from peak of curve towards RHS ; Continuing at the same level as peak / rising (towards RHS) ;

2 marks (d) 1 Stimulates contraction of {uterine muscle / uterus} ; 2 Pushing {fetus / baby} out ; 3 Ref to delivery of placenta ; 4 Stimulates contraction of cells in breast ; 5 Propels milk into ducts / eq ;

4 marks

Total 9 marks

Summer 2006 6112 Unit 2H Mark Scheme

Page 18 6112 June 2006

Unit 2H (6112) Question 1* Maximum mark * common with 6102 External ; Contract ; Increase / eq ; Decreases / eq ;

Total 4 marks


Page 19 6112 June 2006

Question 2* Maximum mark * common with 6102 (a) Cell A Neutrophil / polymorph /granulocyte ; Cell B Lymphocyte / agranulocyte;

2 marks (b) Produces antibodies ; In presence of antigens / attach to antigens/ Correct reference to function of

antibody (e.g. clumping of bacteria)/ reference to the formation of memory cells;

2 marks (c) 1 Contain haemoglobin which {combines/eq} with carbon dioxide ; 2 To form carbaminohaemoglobin/eq ; 3 Presence of carbonic anhydrase ; 4 Formation of {carbonic acid / correct equation} ; 5 Formation of {hydrogencarbonate / correct equation} ;

3 marks

Total 7 marks


Page 20 6112 June 2006

Question 3* Maximum mark * common with 6102 (a) Reference to {blood pressure / hydrostatic pressure} ; Forces out {water (and solutes)/plasma minus the protein} ; Of capillaries ; Reference to {basement membrane / pores} ;

3 marks (b) (i) Protein (molecules) are large / eq ; Cannot pass through {cell membranes / capillary (walls) / eq} ;

2 marks (ii) 1. Sodium ions are small ; 2. Membrane is permeable to sodium ions / sodium ions can {diffuse / pass through}

{cell membrane / capillary (walls) / pores} / eq ; 3. No net diffusion / movement ;

2 marks

Total 7 marks


Page 21 6112 June 2006

Question 4* Maximum mark * common with 6102 (a) (i) Microvillus/ microvilli ;

1 mark (ii) Reference to membrane-bound enzymes/eq ; Named example of enzyme (sucrase, lactase, maltase); Reference to correct substrates and products / enzymes that convert

disaccharides to monosaccharides / eq ; 2 marks

(b) 1. Membrane of {epithelial cell / microvillus} ; 2. Has carrier proteins ; 3. Reference to sodium co-transport ; 4. Reference to active transport ; 5. Reference to facilitated diffusion ; 6. Diffusion (of glucose) into {blood / capillary} from epithelial cell ; 7. Reference to blood flow maintains {diffusion / concentration} gradient ;

4 marks (c) Bread contains starch ; White bread digested more quickly than wholemeal / eq ; Jam contains {sugars / glucose} ; Which are absorbed directly/eq ;

3 marks

Total 10 marks


Page 22 6112 June 2006

Question 5 Maximum mark (a) {Sequence / series / eq} of events each time heart beats ; Atrial systole ; Followed by ventricular systole ; Then diastole ;

3 marks (b) (i) R wave correctly indicated ;

1 mark (ii) Allows atria to contract (fully) ; Before ventricles contract ; Correct reference to {atrial emptying / ventricular filling} ;

3 marks

Total 7 marks


Page 23 6112 June 2006

Question 6 Maximum mark (a) Air pressure decreases (as altitude increases) ; Quantitative comment ;

2 marks (b) (87 – 5 =) 82 (%) ;

1 mark (c) Reference to low pO2 at high altitudes ; Above 3000 m haemoglobin is less saturated with O2 (when breathing air) ; Difference (in saturation) between breathing air and breathing oxygen increases as

altitude increases /breathing O2 increases % saturation ; Reference to oxygen needed to maintain consciousness ; Prevent altitude sickness/ named symptom of altitude sickness / eq;

4 marks

Total 7 marks


Page 24 6112 June 2006

Question 7 Maximum mark (a) 4 ;

1 mark (b) B A D C E ; [correct sequence = 2 marks, one error = 1 mark]

2 marks (c) Halves chromosome number / diploid to haploid / 2n to n ; Diploid restored at fertilisation ; Reference to genetic variation ; Four {sperm / gametes} produced ; From each spermatogonium / eq ;

4 marks (d) Very few sperm reach the ovum / eq ; Reference to some sperm not motile / eq ; Therefore large number needed / eq ; Reference collective activity / eq ;

2 marks

Total 9 marks


Page 25 6112 June 2006

Question 8* Maximum mark * common with 6102 (a) Corpus luteum / yellow body ;

1 mark (b) {Maintenance / eq} of {endometrium / uterus lining} ; Inhibits secretion of {FSH / LH} ; Inhibits secretion of {FSH / LH} releasing hormone ; Inhibits ovulation ; Inhibits prolactin secretion ; Inhibits contraction of uterus ;

2 marks (c) Line drawn from peak of curve towards RHS ; Continuing at the same level as peak / rising (towards RHS) ;

2 marks (d) 1 Stimulates contraction of {uterine muscle / uterus} ; 2 Pushing {fetus / baby} out ; 3 Ref to delivery of placenta ; 4 Stimulates contraction of cells in breast ; 5 Propels milk into ducts / eq ;

4 marks

Total 9 marks

Summer 2006 6103/02 Unit 3 W1 Mark Scheme

Page 26 6103/02 W1 June 2006

Unit 3 W1 (6103/02) (International only)

Question 1 Maximum mark (a)

Time (days) Number of (dead) insects (per 96 cm2) 0 17 14 27 28 6 42 22 56 24 70 20

OR

Time (days) Number of (dead) insects per 16 cm2) 0 2.8 14 4.5 28 1.0 42 3.7 56 4.0 70 3.3

Suitable table with time and totals ; Correct rows and columns with headings and units ; Totals correct ;; [All correct = 2 marks, 1 error = 1 mark, 2 errors = 0 marks]

4 marks (b) F Line graph drawn ; A Axes correct orientation and labelled with units using half paper ; P All points plotted correctly ; L Straight line joins points or good curve through all points ;

4 marks


Page 27 6103/02 W1 June 2006

Question 1 continued Maximum mark (c) {Day 28 / eq} measurements much lower than others ; Comment on wide spread of results even on the same day ; Individual counts range from 0 - 7 ; Suggests some other variable(s) not controlled ;

3 marks (d) Journeys not in same geographical location / eq ; Weather conditions vary / rain may wash off insects ; (Average) speeds will vary ; {Length /time} of journeys will vary ; Use of different vehicles / different positions of number plates / type of number

plate ;

3 marks

Total 14 marks


Page 28 6103/02 W1 June 2006

Question 2 Maximum mark (a) 1. Selection of minimum of five fit and five unfit people ; 2. Definition of {fit and unfit} (for this investigation) ; 3. Two inherent variables controlled (e.g. same sex, same stated age, same mass,

same height, smoker / non smoker ; 4. Two external variables controlled (e.g. time of day, before a meal, before other

exercise) ; 5. Breathing rate measured at rest ; 6. Measured as {number of exhalations / breaths / eq} in {30 seconds / 1 minute} ; 7. Exactly how breathing measured (e.g. touching rib cage / use of bellows sensor/

spirometer) ; 8. Specific exercise type (e.g. exercise bike, step ups) ; 9. Better control of exercise rate (e.g. number of steps per minute / constant speed

of exercise bike) ; 10. Exercise for specific time – minimum 3 minutes ; 11. Breathing rate immediately after exercise measured ; 12. Same stated time for breathing rate to return to normal (before new exercise) ; 13. Record breathing for different exercise rates ; 14. Repeat each exercise for each individual at least twice more ; FOR PULSE RATE: NOT 5, 6 or 7 to a max of 7 marks

9 marks (b) Suitable table of raw data, with correctly labelled rows and columns (including

units) to match the method ; Line graph / bar chart / class frequency histogram ; Correctly orientated and labelled axes (including units) ; Reference to method of calculating percentage increase ;

3 marks


Page 29 6103/02 W1 June 2006

Question 2 continued Maximum mark (c) Limitations: Difficult to define fit and unfit accurately ; Difficult to ensure that exercise rate remains constant ; Difficult to ensure that rest period (between each exercise) is sufficient recovery

time ; Difficult to ensure that exhalations are {involuntary / not artificially induced} /

eq ; Further work: Find breathing rates for a gradation of {fit / unfit} individuals ; Investigate effect of exercise on breathing rates in different sexes/ ages/non

smoker or smoker; Investigate {tidal volume / percentage carbon dioxide} OR percentage oxygen in

exhaled air as a result of exercise ; Investigate the effect of a {training programme / eq} on an individual’s breathing

rate after exercise ; 6 marks

Total 18 marks

Summer 2006 6103/03 Unit 3 Mark Scheme

Page 30 6103/03 June 2006

Unit 3 paper 3 (6103/03) Question 1 Maximum mark (a) 1. Reference to {saprobiont / saprophytic} ; 2. {Digests/eq} {dead / non-living / eq} material ; 3. {By secreting/eq} {proteases / eq} ; 4. Reference to {hyphae / rhizoids} {absorb /eq} amino acids ;

2 marks (b) 1 Reference to {mutualism / symbiosis} ; 2. {Fixes nitrogen / reduces nitrogen / reference to nitrogen fixation} to form {ammonia

/ ammonium / amines} ; 3. Reference to nitrogenase ; 4. {Ammonia / ammonium / amines / product of N-fixation} used to form amino acids ;

2 marks (c) 1. Reference to parasitism / Lives in {{small intestine / ileum / duodenum} of {host /

living organism / named e.g.}} ; 2. Host’s {enzymes digest proteins / proteases} (in food) ; 3. Amino acids absorbed through {body surface / eq} ;

2 marks

Total 6 marks


Page 31 6103/03 June 2006

Question 2 Maximum mark (a) (i) 1. Gases {dissolve / eq} ; 2. Ref. to water in {atmosphere/eq} ; 3. pH 5.5 or lower / more acidic / lower than normal / named acid} ;

2 marks (ii) 1. Readings allow C.E for 2 or more d.p. from graph: {6.7 ± 0.1} and {3.4 ± 0.1} ; 2. Suitable correct working e.g. (3.3 / 6.7) x 100 ; 3. Correct answer e.g. 49(.3) ; [penalise 2 or more d.p once but allow CE]

3 marks (iii) 1. Ref to {legislation/named example}; 2. Desulphurisation / removal of {sulphur / sulphur dioxide} ; 3. Increased {natural gas / biogas / low sulphur fuel} ; 4. CAT converters ; 5. Ref to {alternative energy source / renewable} ; 6. More use of {public transport/eq} ;

2 marks


Page 32 6103/03 June 2006

Question 2 continued Maximum mark (b) 1. {Both /eq} increase mortality ; 2. High aluminium mortality lower than low pH mortality / converse ; 3. Idea of low pH and high aluminium have greater effect than sum of the individual effects / eq ; 4. Manipulated data ;

3 marks (c) 1. {Fewer trout (larvae) survive / trout population falls / eq} ; 2. {Less food / fewer trout to eat / eq} for herons ; 3. Herons {die /move to another area} ; 4. Heron population falls/eq ; 5. Herons eat more {frogs / toads /eq} ; 6. Ref {bioaccumulation /eq} / toxicity of aluminium ;

4 marks

Total 14 marks


Page 33 6103/03 June 2006

Question 3 Maximum mark (a) Producer ; Primary consumer /herbivore ;

2 marks (b) (i) [Allow marking points if describe chondrus in B & C & Enteromorphia in B & C] Rock pool B had {40-45%} Chondrus and no Enteromorpha ; Rock pool C had {95-99%} Enteromorpha and no Chondrus ;

2 marks

(ii) 1. In Rock pool A, Enteromorpha remains {low / none little change} ; 2. But in Rock pool B it increases {after 4 months/ between 4 and 10 months} and then

levels off ; 3. In Rock pool C it falls {after / from} 2 months (through the rest of the period) ;

3 marks

(iii) In Rock pool A the periwinkles eat all of the Enteromorpha ; In Rock pool B the removal of the periwinkles has removed the grazing, so the

Enteromorpha can increase in cover / in Rock pool C the Enteromorpha has decreased because the periwinkles have been added to the rock pool ;

2 marks

(iv) (No Enteromorph) so periwinkles switch to eating Chondrus/ new consumer / ref to

specified environmental change ; 1 mark


Page 34 6103/03 June 2006

Question 3 continued Maximum mark (c) 1. Maximum number of algal species at periwinkle density of 150 periwinkles per m2 / Up to 150 periwinkles per m2 the number of algal species increases and above 150

periwinkles per m2 algal species decrease ; 2. Number of species increase because periwinkles are eating {particular species /

Enteromorpha} / periwinkle grazing stops faster growing algae out competing other species ;

3. Number of species decrease because {periwinkles eat all species / periwinkles eating

algae faster than they can grow/inedible ones survive / faster growing ones survive} ;

2 marks (d) (i) 1. (Raw) sewage ; 2. Fertiliser(s) ; 3. Detergents(s) ;

2 marks (ii) 1. (Excess nutrients) {stimulates / increases} {algae growth / eq} ; 2. Reference to eutrophication in correct context (as excess nutrients) ; 3. {Algae / plants} die ; 4. {Bacteria / decomposers} increase in number ; 5. {Bacteria / decomposers} use up oxygen / oxygen level falls / BOD increases ; 6. Death of {fish / other animals} /increase in {animals/named e.g.} that are adapted to

low oxygen conditions; 4 marks

Total 18 marks

Summer 2006 6104 Core Unit 4 Mark scheme

Page 35 6104 Core June 2006

Unit 4 Core (6104) Question 1 Maximum mark (a) Leaves / seeds/ roots/ stems/ petioles/ flowers/ fruits/ shoots/ coleoptiles / buds ;

1 mark (b) (in dark) slow conversion in darkness (PFR) to PR ; (Infar red light) fast conversion (PFR) to PR ;

2 marks (c) Exposure to {red light / 660 to 700nm / daylight / white light} ;

1 mark

Total 4 marks



Question 2 Maximum mark (a) (i) Type: Effector / motor / multipolar ; Role: {Transmit / eq} impulses to {effectors / muscles / glands / named eg.} ;

2 marks (ii) Arrow drawn points down from cell body to synaptic knob;

1 mark (b) Where: Grey matter ; Importance: {link/eq} with {sensory / relay} neurone / reference to summation ;

2 marks (c) 1. Gap in the myelin sheath /eq ; 2. Enables {depolarisation/action potential/eq} (of axon) ; 3. Causes impulse to jump from node to node / saltatory conduction ; 4. Speeds up (transmission of )impulse ;

3 marks

Total 8 marks



Question 3 Maximum mark (a) 1. Both rise in first half hour ; 2. {Greater/ faster} increase in diabetic men (in first half hour) / converse ; 3. (between 30 to 60 minutes) decreases in non-diabetic men and increases in

diabetic men ; 4. {After one hour/eq} the non-diabetic bgl is lower than the original and diabetic is

higher; 5. Manipulation of comparative figures to support any of above ;

3 marks (b) (i) Insulin causes fall in blood glucose levels ; Blood glucose does not decrease in diabetic men / decrease only seen in non-

diabetic men / allow converse; 2 marks

(ii) 1. Correct reference to effect on respiration ; 2. Osmotic effect of glucose / eq ; 3. Reference to oedema/dehydration of {cells / tissues} / eq ; 4. Reference to change in blood {pressure / pH} ; 5. Coma / death /fainting / nausea / kidney damage ;

2 marks (c) 1. Low level detected by pancreas / islets of Langerhans / α cells ; 2. Glucagon secreted / eq; 3. By α cells ; 4. {Glycogenolysis / gluconeogenesis / eq} stimulated ; 5. (Results in) the release of glucose {into blood / from liver} ;

3 marks

Total 10 marks



Question 4 Maximum mark Maximum 3 marks if no reference to “at these sites” (a) 1. electrons lose energy 2. H+ pumped into intermembrane space ; 3. H+ accumulate / reference to concentration gradient ; 4. Reference to {ATPase / H+ channel /stalked particle} (inner membrane) ;

5. H+ flow (through ATPase) back into matrix ; 6. {Phosphorylation of ADP / ADP + Pi } to ATP ;

4 marks (b) 1. 1 x reduced FAD and 1 x reduced NAD produced / eq ; 2. (1 x) reduced NAD gives 3 ATP molecules ; 3. (1 x) reduced FAD gives 2 ATP molecules ; 4. Because reduced FAD donates {H+ / electrons} after site 1 / eq ;

3 marks (c) Cytoplasm ; Matrix of mitochondria ; Matrix of mitochondria ;

3 marks

Total 10 marks



Question 5 Maximum mark Gross structure: 1. Reference to renal artery and renal vein ; 2. Reference to ureter qualified ; 3. Reference to outer cortex and inner medulla ;

4. Reference to pelvis as a cavity /eq ; Nephron structure: 5. Reference to nephron; 6. Consisting of Bowman’s capsule, proximal convoluted tubule, loop of Henle and

distal convoluted tubule in correct sequence; 7. Reference to glomerulus located inside Bowman’s capsule ; 8. Details of Bowman’s capsule e.g. basement membrane / podocytes ; 9. Reference to wide afferent and narrow efferent arterioles ; 10. Cells of PCT have {microvilli / brush borders / lots of mitochondria; 11. Details given for loop of Henle eg location, relative width of limbs ; 12. Reference to vasa recta ;

13. Details of collecting ducts eg connect to lots of nephrons, location ; [Allow marks from well-labelled diagram]

Total 8 marks

Summer 2006 6104/01 Unit 4 Option A Mark Scheme

Page 40 6104 Option A June 2006

Unit 4A (6104/01) Question 6 Maximum mark

Endotoxin Exotoxin

1. Released once {bacteria have died / cell wall damaged} Released from living bacteria ;

2. Delay between infection and {release / symptoms}

{Released soon after infection / symptoms appear quickly} ;

3. Part of the bacterial cell wall / lipoplysaccharide Protein / enzyme ;

4. Needed in high concentrations to have an effect Effective in very small concentrations ;

5. Example: salmonella / Gram negative only

Example: staphylococcus / Gram negative and positive;

3 marks

λ phage HIV

1. DNA RNA ;

2. No reverse transcriptase Reverse transcriptase ;

3. Complex Polyhedral / icosahedral ;

4. No {envelope / membrane} Enveloped / with membrane;

5. Tail pins/no GP proteins No tail pins / GP proteins;

3 marks

Total 6 marks



Question 7 Maximum mark (a) Fungus / Ascomycetes / Ascomycota/ mould ;

1 mark (b) (i) 1. All nutrients added at beginning of culture / none added during ; 2. Waste products not removed ; 3. Product harvested at end/ eq; 4. pH not adjusted ;

2 marks (ii) 1. (Penicillin is) a secondary metabolite ; 2. Produced {at end of growth phase / during stationary phase} ; 3. Microorganisms {stop growing / enter stationary phase} when {nutrients are depleted / waste products build up / pH falls / anaerobic} ;

2 marks (c) Culture fluid / fraction 2; Because penicillin is secreted /eq ;

2 marks

Total 7 marks



Question 8 Maximum mark (a) 12 x 106 (cells added in the 2 cm3) ; Total volume (22cm3) ; [CE] ÷ 22 = 5.45 x 105 (cells cm-3) ; [CE]

3 marks (b) (i) 1. Neither species of bacteria survive at pH 9 ; 2. The optimum pH for growth of E. coli is pH 8 and for pH 6 for L. bulgaricus ; 3. E. coli cannot survive/eq pH 4, 5(& 9), L. bulgaricus cannot survive 8 (& 9) ; 4. E. coli can survive pH 6 & but L. bulgaricus can survive pH4 ; 5. E. coli can grow at pH 7(& 8), L. bulgaricus can grow at pH 5;(6) & 7 ; 6. L. bulgaricus can tolerate a wider range of pH values than E. coli ; 7. E.coli {grows better/eq} in alkaline conditions but L Bulgaricus {grows better/eq}

in acidic conditions ; 3 marks

(ii) 1. pH affects enzyme (activity)/protein ; 2. They have different enzymes/proteins ;

3. Reference to L. bulgaricus {needing to tolerate {low pH / acidic conditions} / are acidophilic};

4. Because of lactic acid fermentation ;

5. Enzymes needed for {DNA replication / protein synthesis / cell wall synthesis} /

proteins needed for cell transport/eq;

3 marks

Total 9 marks



Question 9 Maximum mark (a) (i) Dilution plating / use of a counting chamber with an exclusions dye (e.g.

methylene blue); 1 mark

(ii) Mix bacteria / sterile technique/eq ;

1 mark (b) (i) 1. Lag phase shown ; 2. Exponential phase shown; 3. Line for exponential phase steeper than that given for glucose ;

3 marks (ii) 1. (Second lag phase / delay before new growth) due to {synthesis/secretion} of

{enzymes/sucrase} ; 2. Time taken to {break down/absorb}{sucrose/products}; 3. More growth due to addition of carbon source / eq ; 4. Growth rate is faster than for glucose because sucrose is a disaccharide / eq ; 5. (Stationary phase results) when sucrose all used up/eq ; 6. Reference to diauxic growth ;

3 marks

Total 8 marks

Summer 2006 6104/02 Unit 4 Option B Mark Scheme

Page 44 6104 Option B June 2006

Unit 4B (6104/02) Question 6 Maximum mark (a) Fungi / ascomycetes / ascomycota/ eq ;

1 mark (b) In {anaerobic respiration / fermentation} ; Ethanol is produced ; 2 marks

Respiration produces CO2 ; Causing dough to rise/eq ;

2 marks

Total 5 marks



Question 7 Maximum mark (a) 74 – 57 (= 17) ; (17) ÷ 74 ; x 100 = {22.97 / 23.0} (%) ;

3 marks (b) Scurvy / Anaemia ;

1 mark (c) 1. Storage {in modified atmosphere / with low oxygen} ; 2. {Packaging / qualified example} (to prevent bruising) ; 3. Coat with wax (to reduce respiration / oxygen entry) ; 4. Keep cool /eq ; 5. Keep out of light/eq ;

2 marks

Total 6 marks



Question 8 Maximum mark (a) {Incubate / eq} at 35 – 40 °C ; For stated time (10 min – 60 min) ;

2 marks (b) 1. Pasteurised sample has failed the test / Pasteurisation not effective ; 2. Indicates bacteria still {active / alive} ; 3. Idea that there are bacteria respiring ; 4. And this causes the colour change ; 5. Reference to redox reactions ;

3 marks (c) 1. No {lactase / β galactosidase} ; 2. Lactose not {digested / eq} ; 3. (Undigested) lactose fermented ; 4. by intestinal bacteria ; 5. Causing {diarrhoea / nausea / abdominal pain / colic / flatulence / eq} ; 6. Reference to osmotic effect of (undigested) lactose in gut ;

4 marks 7. Lactose-reduced milk contains glucose and galactose; 8. Which can be absorbed / whereas lactose cannot be absorbed ;

Total 9 marks



Question 9 Maximum mark (a) (i) Very overweight ; BMI 30 / or above ; Due to excessive {adipose tissue / fat} ;

2 marks (ii) {Relationship between / eq} (body) mass and height ; (A measure of) overweight / underweight ; [BMI = mass (kg) ÷ height (m)2 = 2 marks]

2 marks (b) (i) 1. Overweight increases in children ; 2. But in boys slightly more than in girls ; 3. Obesity increases in children ; 4. Particularly in boys ; 5. Any quantitative comparative figure ;

3 marks (ii) Eating more junk food / eq ; Increased advertising of junk food / eq ; Higher {fat / calorie / carbohydrate} intake ; {More sedentary life style / watching more TV / less exercise} eq ;

2 marks (c) Increased risk of {fractures / high blood pressure / diabetes / (coronary) heart

disease}/eq ; 1 mark

Total 10 marks

Summer 2006 6104/03 Unit 4 Option C Mark Scheme

Page 48 6104 Option C June 2006

Unit 4C (6104/03) Question 6 Maximum mark

Cardiac Striated

1. In heart Attached to {bones / skeleton} ;

2. Intercalated discs / gap junctions / sacromeres irregularly arranged

No intercalated discs / no gap junctions sacromeres regularly arranged ;

3. Branched Not branched ;

4. One nucleus per cell / individual cells Multinucleate / fibres /eq ;

5. Myogenic / involuntary / eq Neurogenic / voluntary/eq ;

6. Does not fatigue /eq Does fatigue /eq ;

3 marks

Myoglobin Haemoglobin

1. Muscle Red blood cells/eq ;

2. Stores oxygen {Transports/eq} oxygen ;

3. Higher affinity / eq Lower affinity / eq ;

4. One sub-unit/eq Four sub-units/eq ;

5. One {oxygen molecule/ haem} Four {oxygen molecules/haem groups} ;

6. Cannot {carry /eq} CO2 Can {carry/eq} CO2 ;

3 marks

Total 6 marks



Question 7 Maximum mark (a) (i) B ;

1 mark (ii) Mitosis ;

1 mark (iii) (Plasma cells) {secrete / produce} antibodies ; (Memory cells) respond to a second {exposure/eq} (to the same antigen) /faster

response to infection / eq ; 2 marks

(b) 1. Receptors on cell surface bind to {antigen / cell / opsin/ particle / named

example} ; 2. Cells engulf {pathogen / eq} / pseudopodia extend around the {pathogen / eq} /

reference to endocytosis ; 3. {Phagosome / (phagocytic) vesicle} is formed (inside the cell) ; 4. Lysosomes fuse with vesicle membrane /eq ; 5. {Secrete/ release} (hydrolytic) enzymes into vesicle ; 6. {Pathogen / antigen} is {digested / destroyed} ;

3 marks

Total 7 marks



Question 8 Maximum mark

(a) (i) 1. (oxygen uptake) increases up to 60dm3 min -1 and then levels off; 2. linear relationship up to 30 dm3 min-1 /fastest up to {20/30} dm3 min-1 ; 3. 30 – 60 dm3 min-1 the increase is less ; 4. credit manipulation of figures ;

3 marks

(ii) 2.5 – 0.40 / 2.10 ; ÷ 0.40 ; x 100 = 525(%) ; answer : 525 %

3 marks (b) 1. Increased numbers of capillaries {around alveoli / in lungs} / increased cardia

muscle /increase stroke volume ; 2. Greater blood flow through the lungs ; 3. Increased numbers of red blood cells ; 4. Increased haemoglobin ; 5. Steeper diffusion gradient / eq ;

3 marks

Total 9 marks



Question 9 Maximum mark (a) 1. Both increase up to the age of 30 and then decrease ; 2. After 30 years of age decrease variable for women but linear decrease in men ; 3. Fastest decrease is between the ages 45 and 55 years for women ; 4. Credit use of comparative figures ;

3 marks (b) (i) Osteoporosis ;

1 mark (ii) 1. Mean bone density is lower in women ; 2. Bone density decreases below {fracture level / (4 a. u.)} ; 3. Faster decline in bone density / lose calcium faster ; 4. Reference to {menopause / less oestrogen} ;

3 marks (iii) Increased {calcium intake / weight bearing exercise} / HRT / regular exercise

when younger/ glucosamine / chondrotinsulphate / bisphosphonates;

1 mark

Total 8 marks


Page 52 6105 June 2006

Unit 5B (6105/01) Question 1 Maximum marks

Plantae / Plants;

Prokaryota / Monera / bacteria ;

Fungi / Fungus ; [ref to moulds = 0]

Animalia / animals ; [ref. to mammals = 0]

Total 4 marks


Page 53 6105 June 2006

Question 2 Maximum marks (a) (gene) {length / eq} of DNA that codes for {polypeptide / protein /eq};

(allele) form of gene /eq ;

2 marks

(b) (i) dominant ;

if recessive not possible to produce child D or G, (as all offspring in second generation

would have to be Dd)/eq explantion ;

2 marks

(b)(ii) B - Dd F - dd J - Dd

[ 2 correct = 1, 3 correct = 2 ]

2 marks

Must use D and d (allow CE for other letters used in (b)(ii))

(b)(iii) 50% / 1 in 2 / 0.5 / ½ ;

(parental genotypes) dd x Dd ;

Clearly indicated gametes ;

offspring genotypes /(at least Dd and dd) ;

3 marks

(c) 1. mutation ;

2. occurs during meiosis /suitable cause of mutation /ref to non-disjunction;

3. causes faulty {protein /polypeptide/eq} to be produced /might not be produced ;

4. recessive/ both parents could be carriers /eq;

5. offspring inherit recessive(allele) from both parents ;

2 marks

Total 11 marks


Page 54 6105 June 2006

Question 3 Maximum marks a) ref. to shape described gives {increased/eq} / surface area ;

1 mark

b) 1. active {uptake / transport} ;

2. {up / against / eq} {concentration gradient / eq} ; 3. {energy /ATP} used ; 4. idea of selective uptake ; 5. by cell membrane ; 6. ref. to ion pumps / carrier protein / channel protein ; 7. ref. to diffusion /facilitated diffusion ;

4 marks

c) reduced NADP / eq +

+ ATP ;

1 mark

d) 1. suitable plant material ; [e.g. maize seedling, duckweed] ;

2. ref. to {culture solution / Sach’s solution} with phosphate missing and ref. to

complete / control with all minerals ; 3. control of specified variable / eq; 4. description of suitable apparatus set up / simple diagram ; 5. left to grow for appropriate time/eq ;

6. ref. to how measured result assessed ;

3 marks

Total 9 marks


Page 55 6105 June 2006

Question 4 Maximum marks

a) 1. addition of phosphate to ADP / eq ;

2. idea of {redox / oxidation} reactions ; 2 marks

b) 1. ref. to phospholipids in membranes ; 2. ROS react with fatty acids in phospholipids ; 3. {damage / disrupt /eq} membrane of {mitochondria / cristae} ; 4. {etc / H+ pumps /stalked particles} {in /across} inner membrane (of mitochondria; 5. {etc / H+} not possible in damaged membrane / eq ;

3 marks

c) 1. {deletion / substitution / addition} of {a / single} {nucleotide/ base}

in a DNA;

2. (triplet) codes for different amino acid / ref to frame shift ; 3. sequence of amino acids (in enzyme) altered ; 4. {shape / tertiary structure} of {enzyme / superoxide dismutase / active

site} altered ; 5. {substrate / superoxide} {no longer fits / unable to bind with} {enzyme /

superoxide dismutase / active site} / ref. enzyme-substrate complex cannot form ;

6. (therefore) superoxide {not removed / eq};

4 marks

Total 9 marks


Page 56 6105 June 2006

Question 5 Maximum marks (a) 1. {long / pointed} canines for {stabbing prey / holding prey / eq} ;

2. {premolars / molars/ carnassials} have {sharp edges / eq} for {shearing/eq} ;

3. incisors for nibbling meat off bones ; 2 marks

(b)(i) 1. correct comparison of rodents in the diet ;

2. correct comparison of {small pets / human food /berries} in the diet ;

3. general comparison of the diet [Note: not essential to use figures, but if used must be correct]

2 marks

(b)(ii) diet would provide more energy ;

need to eat a smaller quantity of food ; less time spend {hunting /eq} ;

2 marks

(c)(i) 1. more territories in a given area ; 2. greater carrying capacity ; 3. Population would be greater/population density greater ;

2 marks

(c)(ii) any ONE from the following list: disease, predation, climate / weather, water supply, stress, availability of dens / shelter, pest control, road kill ;

1 mark


Page 57 6105 June 2006

Question 5 continued Maximum marks

(d) 1. Interruption of gene flow between rural and urban foxes / rural and urban populations become separated /no breeding between rural and urban foxes ;

2. by a barrier / behavioral differences ; 3. different environmental conditions either side of barrier ; 4. different selection pressures / different alleles selected for ; 5. formation of two different gene pools ; 6. difference in physical characteristics / dentition ; 7. correct ref to {allopatry /sympatry}

4 marks

Total 13 marks


Page 58 6105 June 2006

Question 6 Maximum marks a) 1. {malathion/inhibitor} similar shape to {substrate /acetylcholine} ;

2. blocks active site;

3. prevents {entry I eq} of {acetylcholine / substrate};

2 marks

b) 1. acetylcholine allows impulse to pass across gap/eq;

2. acetylcholine binds to receptor on post synaptic membrane ;

3. (causes) depolarisation/ action potential ;

4. malathion {inhibits I prevents action of} acetylcholinesterase;

5. (therefore) acetylcholine not {hydrolysed I broken down} ;

6. (results in) idea of {further I continued I over} stimulation of post-synaptic

membrane /{more I too many} impulses transmitted;

7. idea of over-stimulation of {muscles I glands I eq} / idea of loss of coordination;

5 marks


Page 59 6105 June 2006

Question 6 continued Maximum marks

c) 1. (chemicals) {rapid I quicker result} / easier to apply;

2. idea of storage only temporary I cannot establish long-term balance of organisms

used in biological methods;

3. difficult to remove control organisms from fruit etc;

4. ref. to reliability /kills all the insects ; 2 marks

d) 1. (biodegrade organophosphates are not being used) so percentages fall ;

2. (non-biodegradable) {do not break down I persist / accumulate in

environment};

3. (therefore) remain on {fruit I vegetables I grains};

4. so other {detectable/non biodegradable} residues/eq will increase;

3 marks

Total 12 marks


Page 60 6105 June 2006

Question 7 Maximum marks (a) {chemical energy / carbohydrates stored} / {energy fixed/ eq} ;

in {producers / green plants/ by {photosynthesis / autotrophic nutrition} ;

2 marks

(b)(i) 180 - 145 = 35;

(5 / 35) x 100 or other intermediate stage ;

= 14.3 (%) ;

3 marks

(b)(ii) 1. {decompose / breakdown / rot /eq} {dead bodies / remains/eq} ;

2. using external digestion ;

3. to release {nutrients / nitrates / eq} / recycling of nutrients ;

2 marks

(b)(iii) 1. temperature lower ;

2. lower enzyme activity ;

3. shorter growing season / less sunlight / less suitable wavelength of light ;

4. less photosynthesis ;

5. less water ;

2 marks

(c) 1. replanting after harvesting trees ;

2. selective felling of timber trees, leaving rest of forest intact ;

3. {pollarding/ coppicing} / harvesting/eq on rotation ;

4. (coppicing)trees cut at ground level and allowed to regrow /(pollarding)

cut leaving short trunk idea and regrow;

5. for 4 -25 years and then harvested ;

6. plant fast growing species of trees ;

3 marks

Total 12 marks


Page 61 6115 June 2006

Unit 5H (6115/01) Question 1 Maximum marks Apes humans / hominoids ;

New world monkeys /eq ;

Lemurs /lemuroidae /prosimians ;

Old world monkeys/eq ;

Total 4 marks


Page 62 6115 June 2006

Question 2* Maximum marks * common with 6105 (d) (gene) {length / eq} of DNA that codes for {polypeptide / protein /eq};

(allele) form of gene /eq ;

2 marks (e) (i) dominant ;

if recessive not possible to produce child D or G, (as all offspring in second generation

would have to be Dd) /equivalent explantion;

2 marks

(b)(ii) B - Dd F - dd J - Dd

[ 2 correct = 1, 3 correct = 2 ]

2 marks

Must use D and d (allow CE for other letters used in (b)(ii))

(b)(iii) 50% / 1 in 2 / 0.5 / ½ ;

(parental genotypes) dd x Dd ;

Clearly indicated gametes ;

offspring genotypes /(at least Dd and dd) ;

3 marks (f) 1. mutation ;

2. occurs during meiosis /suitable cause of mutation /ref. to non-disjunction ;

3. causes faulty {protein /polypeptide/eq} to be produced /might not be produced;

4. recessive/ both parents could be carriers /eq;

5. offspring inherit recessive(allele) from both parents ;

2 marks

Total 11 marks


Page 63 6115 June 2006

Question 3 Maximum marks a) sagittal {crest / ridge} /eq ;

1 mark b) 1. {shape/angle} of {hip joint /pelvis};

2. structure of foot / e.g. arching , lack of opposable toe ; 3. fossil footprints ; 4. {s-shaped/eq} spine ; 5. position of spine in relation to skull ;

2 marks

c) 1. ref. to ice age ;

2. less rainfall ;

3. reduction of forest areas ; 4. increase in {grasslands / savannah} ; 5. (hominid) could walk upright ; 6. (therefore) able to survive on grasslands / less dependent on forests ;

3 marks d) 1. ref. to PCR to increase / amplify sample ;

2. ref. to {temperature increase/heat} to break H-bonds ; 3. strands separate ; 4. ref. to cooling {anneals / joins / eq} two strands from different

samples; 5. temperature increased ; 6. higher temperature needed to separate strands, closer the relationship / eq ;

4 marks

Total 10 marks


Page 64 6115 June 2006

Question 4* Maximum marks * common with 6105

b) 1. addition of phosphate to ADP / eq ;

2. idea of {redox / oxidation} reactions ; 2 marks

b) 1. ref. to phospholipids in membranes ; 2. ROS react with fatty acids in phospholipids ; 3. {damage / disrupt /eq} membrane of {mitochondria / cristae} ; 4. {etc / H+ pumps /stalked particles} {in /across} inner membrane (of mitochondria; 5. {etc / H+} not possible in damaged membrane / eq ;

3 marks

d) 1. {deletion / substitution / addition} of {a / single} {nucleotide/ base}

in a DNA;

2. (triplet) codes for different amino acid / ref to frame shift ; 3. sequence of amino acids (in enzyme) altered ; 6. {shape / tertiary structure} of {enzyme / superoxide dismutase / active

site} altered ; 7. {substrate / superoxide} {no longer fits / unable to bind with} {enzyme /

superoxide dismutase / active site} / ref. enzyme-substrate complex cannot form ;

6. (therefore) superoxide {not removed / eq};

4 marks

Total 9 marks


Page 65 6115 June 2006

Question 5 Maximum marks (a) 1. {long / pointed} canines for {stabbing prey / holding prey / eq} ;

2. {premolars / molars/ carnassials} have {sharp edges / eq} for {shearing/eq} ;

3. incisors for nibbling meat off bones ; 2 marks

(b)(i) 1. correct comparison of rodents in the diet ;

2. correct comparison of {small pets / human food /berries} in the diet ;

3. general comparison of the diet [Note: not essential to use figures, but if used must be correct]

2 marks

(b)(ii) diet would provide more energy ;

need to eat a smaller quantity of food ; less time spend {hunting /eq} ;

2 marks

(c) 1. Interruption of gene flow between rural and urban foxes / rural and urban populations become separated /no breeding between rural and urban foxes ;

2. by a barrier / behavioral differences ; 3. different environmental conditions either side of barrier ; 4. different selection pressures / different alleles selected for ; 5. formation of two different gene pools ; 6. difference in physical characteristics / dentition ; 7. correct ref to {allopatry /sympatry}

4 marks


Page 66 6115 June 2006

Question 5 continued Maximum marks (d) 1. docile / easy to handle /non-aggressive /eq;

2. easy to feed / care for ; 3. herding (in grazing animals);

4. loyalty / desire to live close to humans (dogs) ;

2 marks

Total 12 marks


Page 67 6115 June 2006

Question 6* Maximum marks * common with 6105 a) 1. {malathion/inhibitor} similar shape to {substrate /acetylcholine} ;

2. blocks active site;

3. prevents {entry I eq} of {acetylcholine / substrate};

2 marks

b) 1. acetylcholine allows impulse to pass across gap/eq;

2. acetylcholine binds to receptor on post synaptic membrane ;

3. (causes) depolarisation/ action potential ;

4. malathion {inhibits I prevents action of} acetylcholinesterase;

5. (therefore) acetylcholine not {hydrolysed I broken down} ;

6. (results in) idea of {further I continued I over} stimulation of post-synaptic

membrane /{more I too many} impulses transmitted;

7. idea of over-stimulation of {muscles I glands I eq} / idea of loss of coordination;

5 marks


Page 68 6115 June 2006

Question 6* continued Maximum marks * common with 6105

c) 1. (chemicals) {rapid I quicker result} / easier to apply;

2. idea of storage only temporary I cannot establish long-term balance of organisms

used in biological methods;

3. difficult to remove control organisms from fruit etc;

4. ref. to reliability /kills all the insects ; 2 marks

d) 1. (biodegrade organophosphates are not being used) so percentages fall ;

2. (non-biodegradable) {do not break down I persist / accumulate in

environment};

3. (therefore) remain on {fruit I vegetables I grains};

4. so other {detectable/non biodegradable} residues/eq will increase;

3 marks

Total 12 marks


Page 69 6115 June 2006

Question 7* Maximum marks * common with 6105 (b) {chemical energy / carbohydrates stored} / {energy fixed/ eq} ;

in {producers / green plants/ by {photosynthesis / autotrophic nutrition} ;

2 marks

(b)(i) 180 - 145 = 35;

(5 / 35) x 100 or other intermediate stage ;

= 14.3 (%) ;

3 marks

(b)(ii) 1. {decompose / breakdown / rot /eq} {dead bodies / remains/eq} ;

2. using external digestion ;

3. to release {nutrients / nitrates / eq} / recycling of nutrients ;

2 marks

(b)(iii) 1. temperature lower ;

2. lower enzyme activity ;

3. shorter growing season / less sunlight / less suitable wavelength of light ;

4. less photosynthesis ;

5. less water ;

2 marks (c) 1. replanting after harvesting trees ;

2. selective felling of timber trees, leaving rest of forest intact ;

3. {pollarding/ coppicing} / harvesting/eq on rotation ;

4. (coppicing)trees cut at ground level and allowed to regrow /(pollarding)

cut leaving short trunk idea and regrow;

5. for 4 -25 years and then harvested ;

6. plant fast growing species of trees ;

3 marks

Total 12 marks


Page 70 6106 W2 June 2006

Unit 6 W2 (6106/02) Question 1 Maximum mark (a)

Systolic pressure kPa Numbers of 20 year olds Numbers of 50 year olds 13–13.9 1 0 14–14.9 3 0 15–15.9 6 1 16–16.9 6 4 17–17.9 3 6 18–18.9 1 7 19–19.9 0 2

OR

Systolic pressure kPa Numbers of 20 year olds Numbers of 50 year olds 13–14.9 4 0 15–16.9 12 5 17–18.9 4 13 19–19.9 0 2

Tally chart with suitable size classes (minimum 3) ; Table of values with correct headings and units ; Correct totals for each group ;

3 marks (b) A Axes correct orientation and scale with units and labels; F Contiguous histogram with key; P All points plotted correctly;

3 marks (c) Calculated value (18.1) is greater that critical value at 5% level (2.02) ; (Therefore) there is a significant difference between the (means of) blood

pressure of each age group ; 2 marks


Page 71 6106 W2 June 2006

Question 1 continued Maximum mark (d) Variability comments: Simple comment on range of data / 13.9 – 18.2 kPa for 20 year olds / 15.9 – 19.2

kPa for 50 year olds / eq ; Reference to overlap of values in both groups ; Reference to natural variability in living organisms / statistics test shows very low

probability (well below 5%) that these differences could occur by chance ; Reliability comments: Results appear to be reliable for human testing / within limitations of sample size

/ eq ; 3 marks

Total 11 marks


Page 72 6106 W2 June 2006

Question 2 Maximum mark (a) 1. Stated size of area studied/ stated size of quadrat ; 2. Use of random numbers to select sites OR study of minimum of 20 hoverflies ; 3. Reference to time of study e.g. {time of day, time of year, season} ; 4. Two environmental conditions {considered / recorded} e.g. {temperature /

sunlight / wind speed} ; 5. Ref to control of flower colour ; 6. Use of key to identify {flowers / hoverflies / pollen grains} OR pollen grains from

flowers and use for reference ; 7. Visiting defined, e.g. hoverfly wings not beating ; 8. Record number of hoverflies visiting species in {fixed area / stated quadrat size}

{at fixed intervals / stated times} OR record number of visits of one hoverfly to each species in stated time ;

9. Method of capture of hoverflies – pooter/ (sweep) net ; 10. Method of obtaining gut contents e.g. collect faecal pellets ; 11. (Dissolve each) faecal pellet in {stain / water / alcohol} on a microscope slide /

haemocytometer slide; 12. Count pollen grains using microscope on {high power objective lens / x 400

magnification} ; 13. Return hoverflies to environment / care of plants in wild;

10 marks Style Account is concise and well organised, there is good use of technical vocabulary

and almost no spelling errors 2 marks

There is some lack of organisation, limited vocabulary and a number of spelling

errors 1 mark

The account lacks organisation, there is little or no technical vocabulary and many

spelling errors 0 marks


Page 73 6106 W2 June 2006

Question 2 continued Maximum mark (b) Table of raw data matched to method, with accurately labelled rows and columns

(with units) ; Suitable graphical format matched to suggested results table ; Reference to calculation of means OR graph comparative ; Stated null hypothesis (accept from plan) ;

4 marks (c) Limitations: Hoverflies may only visit one type of flower ; Reference to {too few / too many} hoverflies ; Difficult to track fast moving hoverflies / difficult to {record / identify} activity of

many individuals at same time / hoverflies may not stay in the area investigated ; Hoverflies collected by {sweep net / pooter} not same as those observed / ref to

delay between eating and droppings ;

Sub max 3 Further work: Investigate- Feeding in different species of hover flies ; Feeding at (different ages / different time of year) ; Feeding in different sexes ; Effect of hoverflies on {seed / fruit} production ; Feeding in laboratory trials (using laboratory pupated insects) ;

Sub max 3

5 marks

Total 21 marks

Summer 2006 6106/03 Unit 6 Synoptic Mark Scheme

Page 74 6106/03 June 2006

Unit 6 Synoptic (6106/03) Question 1 Maximum mark (a) 1. Combines reversibly/eq ; 2. Has a {high affinity/eq} for oxygen at high {partial pressure of oxygen / eq} ; 3. {Low affinity for /eq} oxygen at low {partial pressures of oxygen / eq} ; 4. {Able to transport / combine with} carbon dioxide /eq ; 5. Each haemoglobin molecule can carry {four molecules / eight atoms of oxygen} ; 6. Bohr effect explained /eq ;

2 marks (b) (i) Fetal haemoglobin: 1.44 /1.45 /1. 46 AND Maternal haemoglobin: 1.94 / 1.95 /1.96 ;

1 mark (ii) 1. Reference to higher affinity for oxygen (than maternal haemoglobin)/converse; 2. At given partial pressure of oxygen ;

3. Oxygen transferred from maternal {haemoglobin/blood/eq} (to fetal haemoglobin) ;

4. In placenta ;

3 marks (c) Gametes shown clearly ; Correct genotypes of offspring ; Probability {0.5 / ½ / 50% / 1 in 2} ;

3 marks

Total 9 marks


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Question 2 Maximum mark (a) 1. An organism which contains {a new gene / new DNA/recombinant DNA} ; 2. Transferred from another species ; 3. (DNA altered) by {gene technology / genetic engineering} ;

2 marks (b) 1. They {eat/reduce numbers of/eq} {insect / pests / named example} ; 2. Which {eat/eq} the (crop) plants / eq ; 3. Reference to biological control ; 4. Act as pollinators / eq ;

2 marks


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Question 2 continued Maximum mark (c) 1. (Herbivores) provide {food / energy source} for {carnivores / secondary consumers

/ higher trophic levels/eq} ; 2. Limit growth of {producers / other herbivores /predators/ eq} ; 3. (Decomposers) break down organic remains / eq ; 4. Reference to {recycling / release of} {nutrients / named example} ;

3 marks (d) (i) 1. Use a quadrat ; 2. Suitable stated size of quadrat (e.g. 0.5 m2) ; 3. Reference to random sampling ; 4. Count number of weeds in quadrat ; 5. Replication ; 6. Density = numbers per (unit) area / explanation of how density calculated ;

4 marks (ii) (GM) maize ; Weeds/surface invertebrates increase/ eq ;

2 marks (e) {Resistance to herbicide in other plants / eq} / {Adverse effect on food chains / eq} ;

1 mark

Total 14 marks


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ESSAY MARK SCHEME Outline Scheme for Marking Essay Questions 3, 4B and 5H

Total maximum mark available: 15 11 available for Scientific content 2 available for Balance 2 available for Coherence Scientific content (S)

Scientific content (S) Description

11 (good)

The essay demonstrates a sound understanding of the topic, contains a significant amount of material relevant to two (or more) Units (including A2 units) of the specification, and includes suitable examples where appropriate. The candidate has clearly and coherently linked together information from different parts of the specification.

9 (above

average)

An above average essay, with accurate content. The essay includes a good balance of material from two (or more) Units (including the A2 units), and examples where appropriate. There may be some minor factual errors.

7 (average)

The essay includes relevant information from two (or more) Units (including A2 units), and the candidate links together some facts and principles. Some examples are included. There may be some minor factual errors.

5 (below

average)

The essay includes some generally factually accurate and relevant material, and there is some attempt to link material from more than one Unit. However, the discussion lacks details, particularly of A2 Units.

3 (poor)

There are some correct facts, but the essay lacks depth and accuracy. Little or no relevant information from A2 Units is included.

1 (poor)

There are very few correct facts. The essay is generally superficial and inaccurate.

0 (poor) No correct, or relevant, information included.

Note: If a scientific content mark of 0, 1, or 3 is awarded, it is very unlikely that a balance

mark of more than 1 is appropriate. S = 11 marks


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Balance (B) 2 Most of the main topic areas outlined are covered

Some discussion of each of the areas chosen, illustrated with suitable examples where appropriate Material included is all relevant to the topic and the candidate has linked information from more than one area of the specification. Few, if any, errors

1 Some of the main topic areas outlined are covered. Some discussion of each of the areas chosen. Some irrelevant material included. There are some examples which link together different areas of the specification. Some errors

0 Very limited account, possibly only one aspect chosen

Material mostly irrelevant No examples of the candidate linking information from different topics Large number of errors

B = 2 marks Coherence (C) 2 Material logically presented, with little or no repetition

Essay has coherence, ideas are developed well; continuous prose used throughout Essay has an introduction and a conclusion, summing up the main points Technical terms have been used correctly Spelling, punctuation and grammar are sound

1 Material is presented in an orderly way and some ideas developed

Continuous prose used throughout The introduction and conclusion may be present, but brief Technical terms are used and generally in the correct context Spelling, punctuation and grammar are generally sound

0 Essay style not used Material in note form or numbered points Very poor standard of spelling, punctuation and grammar

C = 2 marks


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Question 3 Maximum mark Introduction could include outline structure and properties of the cell surface membrane – Specific membrane transport process to include: Diffusion – Facilitated diffusion – Osmosis – [Unit 1] Active transport – Endocytosis – Exocytosis – Illustrated with reference to specific examples such as: Diffusion and gas exchange - [Unit 2 & Unit 5B] Absorption of monosaccharides - [Unit 2] Reabsorption of solutes and water in the nephron - [Unit 4] Movement of ions and release of transmitter substances - [Unit 4]

Scientific content 11 marks Balance 2 marks

Coherence 2 marks

Total 15 marks


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Question 4B Maximum mark Introduction could include reference to the need for the detection of external stimuli – Detection of light by the mammalian eye – Structure of the retina – Rods and cones – [Unit 4] Retinal pigments – Rhodopsin and monochromatic light – Cones and colour perception – Phytochrome and flowering plants – PR and PFR in relation to photoperiod – [Unit 5B] Detection of light direction and auxin –


Coherence 2 marks

Total 15 marks


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Question 5H Maximum mark Introduction could include reference to the structures and functions of the male and

female reproductive systems – Gamete formation involves meiosis – Oogenesis – [Unit 2H] Spermatogenesis – Transfer of male gametes leading to fertilisation – Amniocentesis described as removal of amniotic fluid – Culture of fetal cells – Preparation of karyotype – [Unit 5H] Interpretation of karyotype – e.g. reference to Down’s syndrome – Possible courses of action – Social, ethical and legal implications –


Coherence 2 marks

Total 15 marks

Further copies of this publication are available from Edexcel Publications, Adamsway, Mansfield, Notts, NG18 4LN Telephone 01623 467467 Fax 01623 450481 Order Code UA 017732 Summer 2006 For more information on Edexcel qualifications please visit www.edexcel.org.uk/qualifications Alternatively, you can contact Customer Services at www.edexcel.org.uk/ask or on 0870 240 9800. Edexcel Limited. Registered in England and Wales no.4496750 Registered Office: One90 High Holborn, London, WC1V 7BH

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