AQA A-level Biology Paper 2 June 2025 | 7402/2 Mark Scheme

Please write clearly in block capitals. N N




Centre number Candidate number


Surname

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I declare this is my own work.
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A-level
BIOLOGY
Paper 2 v




Friday 13 June 2025
N v v Morning Time allowed: 2 hours
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Materials ForNExaminer’sNUse
For thisvpapervyouvmust have:
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Question Mark
 avrulervwithvmillimetrevmeasurements
 avscientific calculator. N
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2
Instructions 3
 Usevblack inkvor blackvball-point pen.
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 Fillvinvthevboxesvatvthevtopvofvthisvpage.
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 Answervallvquestions. 5
 Youvmust answer thevquestionsvinvthevspacesvprovided.v Dovnot writev
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outsidevthevboxvaroundveachvpagevorvonvblankvpages. 7
 If youvneedvextravspacevforvyourvanswer(s),vusevthevlinedvpagesvat thevendvofvt
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hisvbook.v Writevthevquestionvnumbervagainst your answer(s). N N
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 Showvall yourvworking.
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 Dovall roughvwork invthisvbook.v Crossvthroughvany work you dovnot want v
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tovbevmarked.
TOTAL
Information
 Thevmarksvfor thevquestionsvarevshownvinvbrackets.
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 Thevmaximumvmarkvforvthisvpapervisv91.




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Answer allvquestionsvinvthevspacesvprovided.
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0 1 .v 1 Invthevfollowingvpassage,vthevnumberedvspacesvcanvbevfilledvwithvbiological terms.
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Glycolysisvisvthevfirst stagevofvrespiration.v It occursvinvthev
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ofvcellsvandvisvanvanaerobicvproc

ess.v Glycolysisvinvolvesvthev (2) v ofvglucosevtovglucose

phosphate,vusingvATP.v Thevoxidationvofvtriosevphosphatevtov (3) v resultsvin

thevnet gainvofvATPvandvreducedv
N (4) v .

Writevthevcorrect biological termvbesideveachvnumbervbelowvthat matchesvthevspacevinvthvev
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passage.
[2vmarks]

1 N




2

3

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0 1 .v 2 Thevequationvforvthevaerobic respirationvofvglucosevis:
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C6H12O6v v +v 6vO2 6vCO2v v +v 6vH2O

Six carbonvdioxidevmoleculesvarevproducedvfromveachvglucosevmolecule.vUse
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vyourvknowledgevofvthevlink reactionvandvKrebsvcyclevtovexplainvwhy.
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[2vmarks]




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0 1 . 3
Anvinhibitorvofvthevelectronvtransfervchainvwasvaddedvtovaerobically respiringvy
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east v cells.
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Asvaerobicvrespirationvwasvinhibited,vthevfollowingvchangesvoccurred:

 oxygenvuptakevdecreased
 ATPvproductionvdecreased
 ethanol wasv produced.
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Explainvthevchangesvinvthevyeast cellsvfollowingvthevadditionvofvthevinhibitor.
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[3vmarks]

Oxygenvuptakevdecreasedv




ATPvproductionvdecreasedv




Ethanol wasvproducedv
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Turnvovervforvthevnextvquestion




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IB/M/Jun25/7402/2