GCSE MARKING SCHEME - Prestatyn High School

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GCSE MARKING SCHEMESUMMER 2019GCSE (NEW)BIOLOGY - UNIT 23400U20-1 AND 3400UB0-1 WJEC CBAC Ltd.

INTRODUCTIONThis marking scheme was used by WJEC for the 2019 examination. It was finalised afterdetailed discussion at examiners' conferences by all the examiners involved in theassessment. The conference was held shortly after the paper was taken so that referencecould be made to the full range of candidates' responses, with photocopied scripts formingthe basis of discussion. The aim of the conference was to ensure that the marking schemewas interpreted and applied in the same way by all examiners.It is hoped that this information will be of assistance to centres but it is recognised at thesame time that, without the benefit of participation in the examiners' conference, teachersmay have different views on certain matters of detail or interpretation.WJEC regrets that it cannot enter into any discussion or correspondence about this markingscheme. WJEC CBAC Ltd.

WJEC GCSE BIOLOGY - UNIT 2SUMMER 2019 MARK SCHEMEGENERAL INSTRUCTIONSRecording of marksExaminers must mark in red ink.One tick must equate to one mark (apart from the questions where a level of response mark scheme is applied). Question totals should bewritten in the box at the end of the question.Question totals should be entered onto the grid on the front cover and these should be added to give the script total for each candidate.Marking rulesAll work should be seen to have been marked.Marking schemes will indicate when explicit working is deemed to be a necessary part of a correct answer. Crossed out responses not replacedshould be marked.Credit will be given for correct and relevant alternative responses which are not recorded in the mark scheme.Extended response questionA level of response mark scheme is used. Before applying the mark scheme please read through the whole answer from start to finish. Firstly,decide which level descriptor matches best with the candidate’s response: remember that you should be considering the overall quality of theresponse. Then decide which mark to award within the level. Award the higher mark in the level if there is a good match with both the contentstatements and the communication statements.Marking abbreviationsThe following may be used in marking schemes or in the marking of scripts to indicate reasons for the marks awarded.caoecfbod correct answer only error carried forward benefit of doubt WJEC CBAC Ltd.1

FOUNDATION TIERQuestion1(a)(b)(i)Marks availableMarking detailsFalse/ F/ True/ T/ True/ T/ (ii)True/ T/ 4 correct 3 marks 3 correct 2 marksblood(i)Any two ( 1) from(Researchers/ they)Large(r) number of people/ they used600 people (1)for a long(er) (time)/ over two years(1)used placebo / used two groups intest / did not know whether had drugor not (1)AO1AO212AO3TotalMathsPrac32 correct 1 mark1122HospitalSmall(er) number of people/hospital used (only) 10people (1)Short(er) time/ (only) 1month (1)Did not use placebo/ onlyone group/ all knew theyhad the drug (1)If use hospital must be clear(ii)(tablet that) does not contain any of the drug11(iii)As a control /comparison/ To ensure that the effects seen arecaused by the drug / to see if there is a difference between theplacebo and the drug11(iv)C11(c) Fewer ethical problems /(Computer programs/ tissue culture/ they) will give moresimilar results to the human body/ Animals (are differentspecies and may) give different results (from humans)/Computer programmes generate large quantities of datamore rapidlyTotal for question 1 WJEC CBAC Ltd.52411110101

Question2(a)(b)Marks availableMarking detailsAO1(i)Fair testing / or description of/ different volumes of milk {willhave different numbers of bacteria/ give different number ofcolonies}Accept reverse answer(i)Flame loop/ use Bunsen burner/ make it red hot (1){kill/ destroy} bacteria/ reference to aseptic (1)(iii)Cover with lid {secure with tape / sealed}(i)212212IIAll correct plots 2 marks4 correct plots 1 markAccurate line label - 35 C (1)2211I6 2 marks Accept any answer 5 - 79.5-3.5 1 markII502242211 (Storage temperature was) too high, allows bacterial growth(1) {no/ open lid} allows {bacteria/microorganisms} to enter (1) (Bacterial growth in) yogurt could cause infection / foodpoisoning/ cause {gut/ stomach/ intestinal} infection (1) Do notcredit illness/ sick113133Prac11(At all three temperatures) bacteria increase over time (1)Higher temperature gives increase in bacteria (1)Maths11Total for question 2 WJEC CBAC Ltd.1TotalScale correct with label -Time (of storage) hours (1)(ii)(c)AO3IIII(iii)AO2851645

Question3(a)(i)(ii)(b)Marks availableMarking detailsAO1Forms a barrier (against microorganisms)/ stops bacteria/owtteReject diseaseA erector muscle (1)B sweat gland (1)Indicative content: Reduces heat loss/ retains heat Erector muscles contract, Hairs become erect, Traps layer of air/ insulates/ restrict air movement onsurface, Sweating reduced / no sweat{Decreased/ no} evaporation (from skin surface) Blood vessels constrict, become narrower/ vasoconstrictionLess blood near skin surfaceShivering – releases heat (energy)5-6 markThree elements,7-9 indicative points;There is a sustained line of reasoning which is coherent,relevant, substantiated and logically structured. The candidateuses appropriate scientific terminology and accurate spelling,punctuation and grammar. WJEC CBAC Ltd.4AO2AO3Total1122MathsPrac

QuestionMarks availableMarking details3-4 marks4-6 points of indicative contentThere is a line of reasoning which is partially coherent, largelyrelevant, supported by some evidence and with some structure.The candidate uses mainly appropriate scientific terminologyand some accurate spelling, punctuation and grammar.AO1AO23363AO3TotalMathsPrac0061-2 marks1-3 points of indicative contentThere is a basic line of reasoning which is not coherent,largely irrelevant, supported by limited evidence and withvery little structure. The candidate uses limited scientificterminology and inaccuracies in spelling, punctuation andgrammar.0 marks: No attempt made or no response worthy of credit.Total marks for question 3 WJEC CBAC Ltd.509

Question4(a)AO2AO3TotalBordetella pertussis11(ii)Antigens ,LymphocytesAntibodiesAll 3 correct 2 marks2 correct 1 markB22(i)(ii)(d)AO1(i)(b)(c)Marks availableMarking details1286.5/ 287(%) 2 marks7 730 - 2 000 / 2 000 100If incorrect award 1 mark for eitherMethod correct with incorrect answer286When vaccination rate {high/at target /95%} the number ofcases was low. (1)When vaccination rate was {low/ decreased} number of cases{was high/ increased} (1)22(i)(Whooping cough is) {serious /fatal/ can kill} (1)Vaccination rates are below {target percentage/ 95%} (1)22(ii)Parental freedom of {choice /responsibility} /against religious beliefs/(Worries) about side effects/ causes {harm/ allergies}Accept reference to concerns about autism e.g. they think itcauses autism11(5) 1 (6) 2 (4) 3All correct 2 marks2 correct 1 mark22(e)Total marks for question 4 WJEC CBAC Ltd.3655Prac122Maths13220

Question5(c)(e)AO2AO3TotalMathsPrac11(i)Prevention of bias111(ii)Any three ( 1) from Place tapes/ mark grid (1) Roll dice/ random number generator (1) To determine coordinates/ owtte (1) Count plants in quadrat (1) Repeat technique in both areas (1)333(i)311I16 8 1281111II128 3 384 ecf (i) (ii)I1111(ii)(d)AO1Biological control / biocontrol.(a)(b)Marks availableMarking details(i)The fungus has reduced the number of plants/ no fungus moreplants(ii)Other (scientists) repeat the investigation/ check someoneelse’s results(i)To check if the fungus {does not/ does} {affect/ kill/ harm}{non-target/ other} {species/ organisms/ plants}(ii)(Biodiversity) would be reduced / it would be less1Total marks for question 57 WJEC CBAC Ltd.711111111411237

Question6/1(a)(b)Marks availableMarking detailsAO1AO2AO3Total(i)2311(ii)Male XYFemale XX11(iii)XYXXXXYXXXXYCorrect gametes X and Y symbols onlyCorrect mechanicsAllow ecf from (ii) and from gametes to offspring1121.76 (to two dp) 2 marks 22(i)(ii)(c)IFemale mean 12.35 /7 1.7642 1 markMales are taller than females1Investigation shows female average height is greater thanmales so hypothesis is not supported. Accept figuresIIIIncrease sample size/Should all be over 25 / all reached full height11Requesting information for heights (rather than measuringheights)Ignore references to conversion of units11410 WJEC CBAC Ltd.284Prac21IITotal marks for Question 6/11Maths121124

Question7/2(i)(ii)(c)AO1A form of a gene (1)Characteristic only shows {when no dominant allele present/when homozygous/ when two recessive alleles are present} /hidden if a dominant allele is present/ not seen in heterozygouscondition (1)Causes a change in {DNA /gene/ genetic code/ triplet code/order of bases}(a)(b)Marks availableMarking detailsAO3Total2211I1 and 211IINo child will have CF. (1)6 does not have the recessive CF allele and 5 gives only oneallele to offspring (or other wording) (1)22(i)Using an inhaler/ breathed in/ inhaled/ nebuliser(ii)The {DNA/genes} must enter the lung cells (1)The gene must function in the {cells/body}/ gene must enter{DNA/ nucleus} (1)Not a cure as lung cells with the new {gene/DNA} die /replaced by cells {without the {gene/ allele} with the CFmutation / recessive allele} (1)1Total for question 7/2 WJEC CBAC Ltd.AO29MathsPrac00121643010

Question3(a)(i)AO1AO2AO3Total(organ which) {responds to/ detects} {stimuli/ named stimulus}/(an organ that) contains receptor cells (1)Brain and spinal cord (1) Reject spine/ backbone1111(iii){Fast/ rapid/ instantaneous/ immediate} {automatic/ without thought/ involuntary} {Protective/ prevent injury} (1)11(i)receptor correctly labelled at end of dendrites (1) Accept (i) aslabel11(ii)motor neurone correctly labelled (1) Accept (ii) as label11(ii)(b)Marks availableMarking details(c)Any one ( 1) from reflex actions {are slowed down / don't happen}/ {no/ slower} response/ {no/ slower} muscle contraction/ effector {does not workproperly/ not stimulated}/ Electrical impulses {do not travel/ travel slower} alongmotor neurone (1)Total for Question 3 WJEC CBAC Ltd.31021116MathsPrac00

Question4(a)AO1AO2AO3Total(i)Chlamydia trachomatis/ Chlamydia trachmatis (1)11(ii)bacteria (1)11use of condoms / celibacy (1) NOT protection unqualified11(b)(c)Marks availableMarking details(i)(ii)(d)3 876 2 marksAward 1 mark for5 452 0.7113 876.3723 877/ 3 875Prac227/ 7.407/ 7.4/ 7.41 2 marksAward 1 mark for5 452 - 5 076 376(376 5 076) 100222Any two ( 1) from:Has been an increase in number of young people withchlamydia (1)Can lead to infertility (if not treated)/ causes conjunctivitis inbabies (1)To try and reduce the number of cases of chlamydia (1){Share information/ education} on {prevention methods/ safesex} (1)Total for Question 4 WJEC CBAC Ltd.Maths31142222940

Question5(a)(b)Marks availableMarking detailsAO1AO2AO3Total(i)Does not have a {vertebral column/ backbone} (1)11(ii) Avoids confusion {in different parts of the world / languages/countries} Avoid duplication caused by common names}/ Name is universal/ recognised in all countries (1)11(i)3762 2 marksIf incorrect award 1 mark for(198 152) 830 096 8(ii)4 / 4.2 / 4.18 2 marksIf incorrect award 1 mark forcalculation of area 30 30 900 / 900 m2calculation of density 3762/900ECF from (i)Any two ( 1) from no death no immigration/emigration/ owtte marking technique does not affect chances of survival no births/ reproduction/ owtteAny one ( 1) from survey more than one area of the parkland / increase area sampled/ repeat at different times of year/ idea of reproducibility(c)(d) WJEC CBAC Ltd.21222MathsPrac2222222111

Question(e)Marks availableMarking detailsAO1Any two for 1 mark from: do not litter avoid trampling replace snails in the area from which they were collected minimise disturbance to other flora and fauna/ owtte use non-toxic paint/ non-permanent paint/ use less obviousmarkingTotal for Question 5 WJEC CBAC Ltd.AO2TotalMathsPrac1413AO341121047

Question6(a)(b)Marks availableMarking detailsAO1correct labelling of aorta /i) (1)correct labelling of medulla/ (ii) (1)Indicative content Brain {monitors/ controls} water levels Water levels in blood low / blood is concentrated (more) ADH released into the blood Correct ref to negative feedback/ osmoregulation (More ADH ) more reabsorption (by kidney) back into blood Volume of urine is less / less urine Concentrated urine5-6 marks7-9 indicative pointsThere is a sustained line of reasoning which is coherent, relevant,substantiated and logically structured. The candidate usesappropriate scientific terminology and accurate spelling, punctuationand grammar.3-4 marks4-6 indicative pointsThere is a line of reasoning which is partially coherent, largelyrelevant, supported by some evidence and with some structure. Thecandidate uses mainly appropriate scientific terminology and someaccurate spelling, punctuation and grammar. WJEC CBAC Ltd.143AO2AO3TotalMathsPrac2020030600

QuestionMarks availableMarking detailsAO1AO2AO3TotalMathsPrac3508001-2 marks1-3 indicative pointsThere is a basic line of reasoning which is not coherent, largelyirrelevant, supported by limited evidence and with very littlestructure. The candidate uses limited scientific terminology andinaccuracies in spelling, punctuation and grammar.0 marks: No attempt made or no response worthy of credit.Total for Question 6 WJEC CBAC Ltd.15

Question7(a)(b)(c) WJEC CBAC Ltd.Marks availableMarking detailsAO1Cutting DNA (into short pieces) (1)which are then separated into bands (1){Some/half} of the lambs {bands/DNA} comes from the ram and{some/half} comes from the sheep (1)showing that the lamb is related to both the ram and the sheep(1)2Health benefit {identifying/ predicting} {disease/ health issues}/early diagnosis leads to early treatment (1)Ethical concern ownership issues / privacy / insuranceproblems/ embryonic screening leading to {designer babies/abortion} (1)1Total for Question 7316AO2AO3TotalMathsPrac00211121226

Question8(a)(b)(i)(ii)(c)(d)Marks availableMarking detailsAO1One bacterium will give rise to one colony/ 22 colonies on agarso 22 bacteria in original sample (1)36.5- 37.5 C (1)human pathogen grows better at body temperature (1)1Any two ( 1) from: Sterilisation of {dishes/agar} / use of {autoclave/ pressurecooker} for agar (1) Glass spreader sterilised/ flamed (1) Petri dish lid not raised too high (1) Lids secured with tape (1) Flame mouth of test tube (1) Working close to bunsen burner (1)7.3 104 3 marks (use of standard form)If incorrect award 2 marks forNumber of colonies/cm3 22 0.0003 73 333.33 3 10-4 cm373.3 1037.3 10x7.6 104 (used 23 colonies instead of 22)If incorrect award 1 mark0.3 1 000 0.0003 1 markNumber of colonies/cm3 23 0.0003 76 666.66 (used 23colonies instead of 22)2(i)Any value within range 3% 4%(ii)Use (a range of) concentrations between 3 % and 4 % (1)(e) WJEC CBAC Ltd.AO223Total for Question 86MathsPrac1223Test on cells/ tissues (1)Test on (named) animals (1)Test on healthy {volunteers/ people} (1)Total1(1)17AO332331111113341338

Question9Marks availableMarking detailsAO1AO2AO3Total(a)Allows light in (to the eye) / {refracts/ bends} light (1)11(b){Undifferentiated/ unspecialised} cell can {develop/ change/specialise/ differentiate} into other cells (1)11(c)Mitosis (1) correct spelling onlyProduces {large/increased} number of cells (1)that are {genetically identical/clones} (1)(d)No stem cells available (from the eye) (1)(e)Any two ( 1) from: Do not have to use stem cells from embryos/ stem celldonor is not required No rejection issues No ethical issues Less invasiveAccept reverse argument for example 23 WJEC CBAC Ltd.22185Prac0031Total for Question 9Maths1218

FOUNDATION TIERSUMMARY OF MARKS ALLOCATED TO ASSESSMENT OBJECTIVESQuestionAO1AO2AO3TOTAL 376244102476401000TOTAL323216801117 WJEC CBAC Ltd.19

HIGHER TIERSUMMARY OF MARKS ALLOCATED TO ASSESSMENT OBJECTIVESQuestionAO1AO2AO3TOTAL 0U20-1 3400UB0-1 WJEC GCSE Biology - Unit 2 MS S19/DM WJEC CBAC Ltd.20

A level of response mark scheme is used. Before applying the mark scheme please read through the whole answer from start to finish. Firstly, decide which level descriptor matches best with the candidate’s response: remember that you should be considering the overall quality of the response. Then deci

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