A-level Biology Mark Scheme Paper 3 June 2017
marksphysicshelpA-LEVELBIOLOGY7402/3Mark scheme7402June 2017Version: 1.0 FinalMPH
MPHMark schemes are prepared by the Lead Assessment Writer and considered, together with therelevant questions, by a panel of subject teachers. This mark scheme includes any amendmentsmade at the standardisation events which all associates participate in and is the scheme which wasused by them in this examination. The standardisation process ensures that the mark scheme coversthe students’ responses to questions and that every associate understands and applies it in the samecorrect way. As preparation for standardisation each associate analyses a number of students’scripts. Alternative answers not already covered by the mark scheme are discussed and legislatedfor. If, after the standardisation process, associates encounter unusual answers which have not beenraised they are required to refer these to the Lead Assessment Writer.It must be stressed that a mark scheme is a working document, in many cases further developed andexpanded on the basis of students’ reactions to a particular paper. Assumptions about future markschemes on the basis of one year’s document should be avoided; whilst the guiding principles ofassessment remain constant, details will change, depending on the content of a particularexamination paper.Further copies of this mark scheme are available from aqa.org.ukCopyright 2017 AQA and its licensors. All rights reserved.AQA retains the copyright on all its publications. However, registered schools/colleges for AQA are permitted to copy material from thisbooklet for their own internal use, with the following important exception: AQA cannot give permission to schools/colleges to photocopy anymaterial that is acknowledged to a third party even for internal use within the centre.
MPHMARK SCHEME – A-LEVEL BIOLOGY – 7402/3 – JUNE 2017Mark scheme instructions to examiners1. GeneralThe mark scheme for each question shows: the marks available for each part of the question the total marks available for the question the typical answer or answers which are expected extra information to help the examiner make his or her judgement and help to delineatewhat is acceptable or not worthy of credit or, in discursive answers, to give an overview ofthe area in which a mark or marks may be awarded.The extra information in the ‘Comments’ column is aligned to the appropriate answer in theleft-hand part of the mark scheme and should only be applied to that item in the markscheme.At the beginning of a part of a question a reminder may be given, for example: whereconsequential marking needs to be considered in a calculation; or the answer may be onthe diagram or at a different place on the script.In general the right-hand side of the mark scheme is there to provide those extra detailswhich confuse the main part of the mark scheme yet may be helpful in ensuring thatmarking is straightforward and consistent.2. Emboldening2.1In a list of acceptable answers where more than one mark is available ‘any twofrom’ is used, with the number of marks emboldened. Each of the following bulletpoints is a potential mark.2.2A bold and is used to indicate that both parts of the answer are required to awardthe mark.2.3Alternative answers acceptable for the same mark are indicated by the use of OR.Different terms in the mark scheme are shown by a / ; eg allow smooth / freemovement.3. Marking points3.1Marking of listsThis applies to questions requiring a set number of responses, but for whichstudents have provided extra responses. The general principle to be followed insuch a situation is that ‘right wrong wrong’.Each error / contradiction negates each correct response. So, if the number oferrors / contradictions equals or exceeds the number of marks available for thequestion, no marks can be awarded.However, responses considered to be neutral (often prefaced by ‘Ignore’ in the‘Comments’ column of the mark scheme) are not penalised.3 of 16
MPHMARK SCHEME – A-LEVEL BIOLOGY – 7402/3 – JUNE 20173.2Marking procedure for calculationsFull marks can be given for a correct numerical answer, without any working shown.However, if the answer is incorrect, mark(s) can usually be gained by correctsubstitution / working and this is shown in the ‘Comments’ column or by each stageof a longer calculation.3.3Interpretation of ‘it’Answers using the word ‘it’ should be given credit only if it is clear that the ‘it’ refersto the correct subject.3.4Errors carried forward, consequential marking and arithmetic errorsAllowances for errors carried forward are most likely to be restricted to calculationquestions and should be shown by the abbreviation ECF or consequential in themark scheme.An arithmetic error should be penalised for one mark only unless otherwiseamplified in the mark scheme. Arithmetic errors may arise from a slip in acalculation or from an incorrect transfer of a numerical value from data given in aquestion.3.5Phonetic spellingThe phonetic spelling of correct scientific terminology should be credited unlessthere is a possible confusion with another technical term.3.6Brackets( .) are used to indicate information which is not essential for the mark to beawarded but is included to help the examiner identify the sense of the answerrequired.3.7Ignore / Insufficient / Do not allowIgnore or insufficient is used when the information given is irrelevant to the questionor not enough to gain the marking point. Any further correct amplification could gainthe marking point.Do not allow means that this is a wrong answer which, even if the correct answer isgiven, will still mean that the mark is not awarded.4 of 16
MPHMARK SCHEME – A-LEVEL BIOLOGY – 7402/3 – JUNE 2017Question Marking Guidance01.11. (Nerve impulse/depolarisation of membrane)causes Ca2 channel (proteins) to open;Mark32. Ca2 enter by (facilitated) diffusion;CommentsAccept singlereference to ions tocover 1 and 2Penalise once for noreference to ions3. Causes (synaptic) vesicles to fuse with(presynaptic) membrane;1. Reject carrierproteins3. Reject ref torelease of vesicles3. Ignore vesicles bindto membrane (butaccept merge with)01.21. Myosin head attaches to actin andbends/performs powerstroke;2 max2. (This) pulls mitochondria past/along the actin;1. Accept changeshape/change angle2. Ignore pulls actinalong3. Other/next myosin head attaches to actin (andbends/performs powerstroke);2. Ignore refs tocytoskeleonAccept plural orsingular statements01.31. (Mitochondria) supply (additional) ATP/energy;2. To move vesicles/for active transport of ions/formyosin to move past actinORRe-synthesis/reabsorption ofneurotransmitter/named neurotransmitter;21. Reject producesenergy2. Ignore ref. to ATPfor opening calciumion channels/makingvesicles fuse withmembrane5 of 16
MPHMARK SCHEME – A-LEVEL BIOLOGY – 7402/3 – JUNE 2017Question02.1Marking GuidanceThe bacteriophage has a capsidMark1and the bacterium has a cell-surfacemembrane;Correct number of times between213.0/12.96 and 13.9/13.92 scores 2 marks;;150.7nm to 154.4nm/ 0.151µm to 0.154µmand 1953.5nm to 2097.6nm/ 1.954µm to 2.098µm;The bacteriophage makes no difference to thenumber of (living) bacteria/there will be nodifference in the number of (live) bacteria in treatedand untreated mice/ there will be no difference inthe number of (live) bacteria in A and B;Both lengths requiredfor 1 mark creditAccept refsto150/0.15 and2000/2One mark if correct sizes in ranges of02.3Reject if more thanone box with tick.Ignore crossed-outticksAccept tick to right orleft of correct boxThird box down02.2CommentsIgnore number of sigfig1Ignore no differencebetween mice6 of 16
MPHMARK SCHEME – A-LEVEL BIOLOGY – 7402/3 – JUNE 201702.41. Log scale (on graph) shows big range innumber of bacteria2ORUse of suitable data from log scale to give therange in number of bacteria;1 and 2 Do notaccept simplestatements of log10values from graphLook for answers instandard form2. Some samples too many to count (so dilute) butsome countable (so don’t dilute)Group AMean between 79million and 100 millionORUse of figures from graph relating to ease (orotherwise) of countingRange 4 million to 631millionExample. 631 000 000 bacteria would be too bigto count (without serial dilution), 100 000bacteria is small enough to count;Group BMean between 100thousand and 126thousandRange 3.98/4 up to251 thousand02.51. (Bacteriophage) reduces number of bacteria;2. (In all cases/mice because) ranges don’toverlap;3. But big range of effect/some mice a bigreduction/a few mice with big falls in numberORDoesn’t bring bacteria down to 0 in any/worksfor some (mice) but not for all;3Do not accept justquotes of log10figures direct fromgraphIgnore refs tosignificance2. Reject ref to SD /SE7 of 16
MPHMARK SCHEME – A-LEVEL BIOLOGY – 7402/3 – JUNE 2017Question03.103.2Marking GuidanceMarkTwo suitable examples;;Examples1. amino acid/protein/polypeptide/peptide;2. nucleicacid/nucleotide/base;3. DNA;4. RNA;5. ATP/ADP;6. NAD/NADP (reduced ornot);7. Cyclic AMP/cAMP;8. Chlorophyll;2 max List rule appliesCorrect answer in the range 90 to133.2 scores 2 marks;;CommentsReject for either pointnitrates/nitrites/ammonia/ammonium/urea4. Accept pre-mRNA/mRNA/rRNA/tRNA2Accept positive or negative values1 mark for answers where yieldcalculated correctly for 1970 OR2005;(1970 in range) 170.8 to 176.4OR(2005 in range) 266.4 to 304.0;03.31. Using more but getting lessresponse over time;2. The graph shows correlationbut doesn’t prove changes inyield due to fertiliser/but therecould be other factors;2 maxIdea of over time is important1. accept fertiliser becomes less effectiveover time1. Accept use of figures from graph1. Accept the idea of less grain/crop overtime2.Ignore whether correlation is positive ornegative3. Becomes less cost effectivewith time;8 of 16
MPHMARK SCHEME – A-LEVEL BIOLOGY – 7402/3 – JUNE 2017Question04.1Marking GuidanceCorrect answer of 4.92, 2 marks;;Mark2Accept4.916/4.917/4.931. Eg grid withcoordinates selectedusing random numbertableIf N(N-1) 3540, OR n(n-1) 720, then award 1mark04.21. A method of selecting sampling sites atrandom;2. Use of quadrat;3. Identify (plant) species (at site/in each quadrat)2. Frame or pointOR3. Reject refs to %cover, or countingindividualsCount number of (different plant) species (atsite/in each quadrat);04.31. Significant increase in species richness on Islayand Colonsay and (significant) fall on Harris;2. Change in diversity on Islay not significant;3. Greater than 0.05/5% probability of getting thischange/difference by chance (on Islay)Comments32. Accept converseabout significance ofdifferences in othercasesOR(For other differences) less than 0.001/0.1%probability of getting this change/difference bychance (for species richness on Colonsay, Harris,Islay)OR3. Reject results aredue/not due to chance3. Ignore refs to PunqualifiedLess than 0.01/1% probability of getting thischange/difference by chance (for diversity index onColonsay, Harris);9 of 16
MPHMARK SCHEME – A-LEVEL BIOLOGY – 7402/3 – JUNE 2017Question05.1Marking GuidanceMark1. (DNA) helicase;22. (DNA) polymerase;CommentsList Rule AppliesAccept (DNA) eject RNAAccept phoneticspellings05.21. Changes tertiary structure of the enzyme;22. (Enzyme) active site formed/able to beformed/active site becomes complementary;1. Accept tertiarysymbol 3o1. Ignore 3D2. Reject refs toinhibition/inhibitors2. Ignore refs to E-Scomplexes form2. Ignore refs /phosphate) makes substratesmore reactive/raises their energy level(s)/lowersactivation energy for the reaction;1. ATM will not bind to (broken) DNA;1Ignore providesenergy unqualifiedIgnore refs to kineticenergy unqualified3 max2. DNA not repaired/ cell still has broken DNA;3. Cell division continues/tumour forms;4. Tumour suppressor (gene) not effective/ notactivated;5. May have no effect in diploid/heterozygous(organism);6. (Which) still has a functional ATM/ATM gene;10 of 16
MPHMARK SCHEME – A-LEVEL BIOLOGY – 7402/3 – JUNE 2017Question06.1Marking GuidanceCorrect answer 23.55 – 24 two marks;;MarkComments2For one mark5.9OR94.2;06.21. Method for measuring area;3eg draw round (each) leaf on graph paper andcount squares;2. Of both sides of (each) leaf;3. Divide rate (of water loss/uptake frompotometer) by (total) surface area (of leaves);06.3Plant has roots1ORxylem cells very narrow;06.41. Both small/similar size (so fit channel);Ignore references toair bubbles/massflow/photosynthesisAccept xylemdamaged when cut22. Have a similar shape (so bind to/fit channel);1. Accept same heightand widthIgnore refs topolar/non-polar2.Accept Aquaporincomplementary tooxygen(s)06.51. Single-stranded RNA (has base sequence)complementary to PIP1 mRNA;2. Binds to mRNA (of PIP1)/leads to destructionof mRNA;3. Prevents/reduces translation (of PIP1);3 max3. Less made isinsufficient4. Reduces photosynthesis/named process thatuses water;11 of 16
MPHMARK SCHEME – A-LEVEL BIOLOGY – 7402/3 – JUNE 201706.6Not all of mRNA bound to single-strandedRNA/there is more mRNA than interfering RNA1ORAccept not all cellswith transgenesNot all mRNA destroyed/disabled;06.71. Loss of PIP reduces water and carbon dioxidemovement;2. Differences significant because SDs don’toverlapORNeed stats test to see whether significantdifferences (or not);Accept mutations intransgene,3 max1. Accept converse forwild type2. Reject referencesto results significant ornot significant2. Accept error barsfor SDs3. Greater (proportional) effect on carbon dioxidetransport;4. Not all movement through PIP;12 of 16
MPHMARK SCHEME – A-LEVEL BIOLOGY – 7402/3 – JUNE 2017Question 7 Level of response marking guidanceLevel of response marking instructionsLevel of response mark schemes are broken down into five levels, each of which has a descriptor.The descriptor for the level shows the average performance for the level. There are five marks ineach level. Thus the descriptor for the level represents the mid mark in that level.Before you apply the mark scheme to a student’s answer, read through the answer and annotate it(as instructed) to show the qualities that are being looked for. You can then apply the markscheme.Step 1 Determine a levelStart at the lowest level of the mark scheme and use it as a ladder to see whether the answermeets the descriptor for that level. The descriptor for the level indicates the different qualities thatmight be seen in the student’s answer for that level. If it meets the lowest level then go to the nextone and decide if it meets this level, and so on, until you have a match between the level descriptorand the answer. With practice and familiarity you will find that for better answers you will be able toquickly skip through the lower levels of the mark scheme.When assigning a level you should look at the overall quality of the answer and not look to pickholes in small and specific parts of the answer where the student has not performed quite as wellas the rest. If the answer covers different aspects of different levels of the mark scheme you shoulduse a best fit approach for defining the level and then use the variability of the response to helpdecide the mark within the level. i.e. if the response is predominantly level 3 with a small amount oflevel 4 material it would be placed in level 3 but be awarded a mark near the top of the levelbecause of the level 4 content.Step 2 Determine a markOnce you have assigned a level you need to decide on the mark. The descriptors on how toallocate marks can help with this. The exemplar materials used during standardisation will help.There will be an answer in the standardising materials which will correspond with each level of themark scheme. This answer will have been awarded a mark by the Lead Examiner. You cancompare the student’s answer with the example to determine if it is the same standard, better orworse than the example. You can then use this to allocate a mark for the answer based on theLead Examiner’s mark on the example.You may well need to read back through the answer as you apply the mark scheme to clarifypoints and assure yourself that the level and the mark are appropriate.Indicative content in the mark scheme is provided as a guide for examiners. It is not intended to beexhaustive and you must credit other valid points. Students do not have to cover all of the pointsmentioned in the indicative content to reach the highest level of the mark scheme.An answer which contains nothing of relevance to the question must be awarded no marks.13 of 16
MPHMARK SCHEME – A-LEVEL BIOLOGY – 7402/3 – JUNE 201721–Extended25AbstractGeneralisedbeyond specificcontext16–Relational20Integrated into awholeResponse shows holistic approach to the question with a fullyintegrated answer which makes clear links between severaldifferent topics and the theme of the question.Biology is detailed and comprehensive A-level content, usesappropriate terminology, and is very well written and alwaysclearly explained.No significant errors or irrelevant material.For top marks in the band, the answer shows evidence ofreading beyond specification requirements.Response links several topics to the main theme of thequestion, to form a series of interrelated points which are clearlyexplained.Biology is fundamentally correct A-level content and containssome points which are detailed, though there may be somewhich are less well developed, with appropriate use ofterminology.Perhaps one significant error and, or, one irrelevant topic whichdetracts from the overall quality of the answer.11–Multistructural15covered but theyBiology is usually correct A-level content, though it lacks detail.It is usually clearly explained and generally uses appropriateterminology.are unrelatedSome significant errors and, or, more than one irrelevant topic.UnistructuralResponse predominantly deals with only one or two topics thatrelate to the question.Several aspects6–Response mostly deals with suitable topics but they are notinterrelated and links are not made to the theme of the question.10Only one or fewaspects coveredBiology presented shows some superficial A-level content thatmay be poorly explained, lacking in detail, or show limited use ofappropriate terminology.May contain a number of significant errors and, or, irrelevanttopics.1–5UnfocusedResponse only indirectly addresses the theme of the questionand merely presents a series of biological facts which areusually descriptive in nature or poorly explained and at timesmay be factually incorrect.Content and terminology is generally below A-level.May contain a large number of errors and, or, irrelevant topics.0Nothing of relevance or no response.14 of 16
MPHMARK SCHEME – A-LEVEL BIOLOGY – 7402/3 – JUNE 2017Question Marking Guidance07.1The importance of nitrogen-containing substances inbiological systemsMarkComments253.1.4 and 3.1.4.2 proteins and enzymes3.1.5nucleic acids3.1.5.2DNA replication3.1.6ATP3.2.1.1ribosomes3.2.2cell division3.2.3transport across membranes3.2.4immune response3.3.3digestion and absorption3.3.4.1haemoglobin3.4.1genes and chromosomes3.4.2protein synthesis3.4.3mutation3.4.7investigating itrogen cycle3.6.2nervous coordination3.6.3muscles3.6.4.2control of blood glucose (andpeptide/protein hormones)3.7.1inheritance3.8.1alteration of DNA sequences3.8.2.2regulation of transcription andtranslationIn order to fully address the question and reach the highest mark bands students must alsoinclude at least four topics in their answer, to demonstrate a synoptic approach to the essay.Students may be able to show the relevance of other topics from the specification.Note, other topics from beyond the specification can be used, providing they relate to the title andcontain factually correct material of at least an A-level standard. Credit should not be given fortopics beyond the specification which are below A-level standard.15 of 16
MPHMARK SCHEME – A-LEVEL BIOLOGY – 7402/3 – JUNE 201707.2The importance of diffusion in organisms3.1.7 and .5.43.6.1.13.6.1.23.6.2.13.6.2.23.6.33.6.4.1 and 4.2concentration3.6.4.325water and inorganic ionstransport across membranesgas exchangedigestion and absorptionmass transport in animalsmass transport in plantsDNA and protein synthesisphotosynthesisrespirationnutrient cyclesplant responses to stimulireceptorsnerve impulsessynaptic transmissionmuscle contractioncontrol of blood glucosecontrol of blood water potentialIn order to fully address the question and reach the highest mark bands students must alsoinclude at least four topics in their answer, to demonstrate a synoptic approach to the essay.Students may be able to show the relevance of other topics from the specification.Note, other topics from beyond the specification can be used, providing they relate to the title andcontain factually correct material of at least an A-level standard. Credit should not be given fortopics beyond the specification which are below A-level standard.16 of 16
Jun 03, 2017 · MARK SCHEME – A-LEVEL BIOLOGY – 7402/3 – JUNE 2017. 3 of 16 . Mark scheme instructions to examiners . 1. General . The mark scheme for each question shows: the marks available for each part of the question the total marks available for the qu
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CSEC English A Specimen Papers and Mark Schemes: Paper 01 92 Mark Scheme 107 Paper 02 108 Mark Scheme 131 Paper 032 146 Mark Scheme 154 CSEC English B Specimen Papers and Mark Schemes: Paper 01 159 Mark Scheme 178 Paper 02 180 Mark Scheme 197 Paper 032 232 Mark Scheme 240 CSEC English A Subject Reports: January 2004 June 2004
Matthew 27 Matthew 28 Mark 1 Mark 2 Mark 3 Mark 4 Mark 5 Mark 6 Mark 7 Mark 8 Mark 9 Mark 10 Mark 11 Mark 12 Mark 13 Mark 14 Mark 15 Mark 16 Catch-up Day CORAMDEOBIBLE.CHURCH/TOGETHER PAGE 1 OF 1 MAY 16 . Proverbs 2—3 Psalms 13—15 Psalms 16—17 Psalm 18 Psalms 19—21 Psalms
H567/03 Mark Scheme June 2018 6 USING THE MARK SCHEME Please study this Mark Scheme carefully. The Mark Scheme is an integral part of the process that begins with the setting of the question paper and ends with the awarding of grades. Question papers and Mark Schemes are d
Examiners should mark according to the mark scheme not according to their perception of where the grade boundaries may lie. All marks on the mark scheme should be used appropriately. All marks on the mark scheme are designed to be awarded. Examiners should always award full marks if deserved, i.e. if the answer matches the mark scheme.
MARK SCHEME for the November 2003 question papers 0610 BIOLOGY 0610/01 Paper 1 (Multiple Choice), maximum mark 40 0610/02 Paper 2 (Core), maximum mark 70 0610/03 Paper 3 (Extended), maximum mark 70 0610/05 Paper 5 (Practical), maximum mark 40 0610/06 Paper 6 (Alternative to Practical), maximum mark 40
the mark scheme should be used appropriately. All the marks on the mark scheme are designed to be awarded. Examiners should always award full marks if deserved, i.e. if the answer matches the mark scheme. Examiners should also be prepared to award zero marks if the candidate’s response is not worthy of credit according to the mark scheme.
this and other articles in this Volume. The dis-cussion in this article is limited to the relation-ship between these factors and the induction coil design. Current Flow in the Part Eddy currents are the primary source of power dissipation in most induction heat treat-ing applications. Eddy currents, just like all
