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AQA biology a-level paper 2 questions and
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answers latest top score.
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describe xand xexplain xthe xsteps xin xthe xlight xdependent xreaction xof xphotosynthesis x- x
xcorrect xanswer. x x x1. xphotoionisation: xlight xreaches xchlorophyll xin xPSII, xwhich xis
xabsorbed xby xan xelectron, xwhich xbecomes xexcited xand xmoves xto xa xhigher xenergy
xlevel. x
2. the xelectron xpasses xto xa xcarrier xprotein xin xthe xthylakoid xmembrane, xand xis
xpassed xdown xa xseries xof xcarrier xmolecules xcalled xan xelectron xtransfer xchain. x
3. as xthe xelectron xmoves xdown, xenergy xis xlost xfrom xthe xelectron xand xis xreleased
xas xATP. x4. xthe xloss xof xelectron xfrom xPSII xis x'refilled' xby xan xelectron xproduced xby
xphotolysis, xwhich xalso xproduces xhydrogen xand xoxygen. x
5. the xlost xelectron xreaches xPSI, xwhich xabsorbs xlight xenergy xand xboosts xanother
xelectron xto xa xhigher xenergy xlevel x(excitation). x
6. this xelectron xalso xgoes xdown xan xelectron xtransport xchain. x
7. this xreaches xthe xfinal xelectron xacceptor xwhich xis xa xproton. xthey xcombine xto xform
xH xand xreduce xNADP xto xNADPH. x
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describe xand xexplain xthe xsteps xin xthe xlight xindependent xreaction xpf xphotosynthesis. x-
x xcorrect xanswer. x x x1. xCO2 xdiffuses xinto xstroma xand xcombines xwith xribulose
xbisphosphate x(RuBP) xusing xthe xenzyme xrubisco. x
2. this xforms xan xunstable x6 xcarbon xmolecule, xwhich xsplits xinto x2 x3 xcarbon
xmolecules, xglyercate-3-phosphate x(G3P) x. x
3. G3P xis xreduced xby xNADPH xto xtriose-phosphate x(TP), xwhich xis xaided xby xATP xfor
xenergy. x x
4. TP xcan xbe xconverted xinto xuseful xorganic xsubstances. x
5. TP xcan xalso xbe xreformed xinto xRuBP xusing xATP. x
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describe xglycolysis xin xrespiration. xgive xnet xformation. x- x xcorrect xanswer. x x x1. xglucose
xis xconverted xinto xphosphorylated xglucose xby x2ATP. xthis xmakes xit xvery xreactive, xso xit
xsplits xinto x2 xtriose xphosphate x(TP). x x
2. 2TP xis xthen xoxidised xby x2NAD xand x4 xATP xis xformed xto xform xpyruvate. x
, 3. NET: x2ATP, x2Pyruvate, x2NADH, x2H+ x
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describe xlinks xreaction xin xrespiration. xgive xnet xformation. x- x xcorrect xanswer. x x x1.
xpyruvate xdiffuses xinto xthe xmatrix xof xmitochondria. x x
2. pyruvate xis xoxidised xby xNAD. xCO2 xis xlost. xthis xforms xacetate. x x
3. acetate xand xco-enzyme xA xcombine xto xform xacetyl xco-enzyme xA. x
4. NET: xCO2, xreduced xNAD, xacetyl xco-enzyme xA x
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describe xkrebs xcycle xin xrespiration. xgive xnet xformation. x- x xcorrect xanswer. x x x1. xacetyl
xcoenzyme xA xcombines xwith x4 xcarbon xmolecule x(oxaloacetate) xto xform x6 xcarbon
xcitric xacid. x2. xCO2 xis xlost x(decarboxylation), xmolecule xis xoxidised xby xNAD xand xATP
xis xproduce. xthis xforms x5 xcarbon xcompound. x
3. it xis xoxidised xby x2NADH xand xFAD, xand xis xdecarboxylated. x
4. this xforms x4 xcarbon xmolecule xagain. x
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describe xoxidative xphosphorylation xin xrespiration. x- x xcorrect xanswer. x x x1. xreduced
xcoenzyme xpasses xits xH xto xa xcarrier xprotein xin xthe xETC. xthis xsplits xinto xa xproton xand
xelectron. x
2. the xprotons xpass xthrough xthe xspace xbetween xinner xand xouter xmitochondrial
xmembrane. x
3. electrons xpass xthrough xproteins xon xETC. x
4. protons xreturn xback xvia xATP xsynthase xin xthe xmembrane, xproducing xATP. x
5. the xprotons xand xelectrons xrecombine xto xform xH, xwhich xcombines xwith xO xto xform
xwater. x
6. oxygen xis xthe xlast xelectron xacceptor xin xthe xETC. x
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define xbiomass x- x xcorrect xanswer. x x xthe xtotal xmass xof xorganisms xin xa xgiven xarea x
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what xis xthe x'gross xprimary xproduction' x- x xcorrect xanswer. x x xthe xchemical xenergy
xstored xin xa xplants xbiomass x
x
what xis xthe x'net xprimary xproduction' x- x xcorrect xanswer. x x xthe xchemical xenergy xstores
xin xa xplants xbiomass xafter xrespiratory xlosses xhave xbeen xconsidered. xthis xenergy xis
xavailable xto xconsumers. x
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how xcan xyou xcalculate xthe xnet xprimary xproduction? x- x xcorrect xanswer. x x xNPP x= xGPP
x- xR xwhy xis xconverting xsunlight xenergy xinto xbiomass xin xproducers xinefficient? x- x
xcorrect xanswer. x x xsome xlight xisn't xthe xcorrect xwavelength xto xbe xabsorbed xsome xlight
xdoesnt xhit xchloroplast xsome xlight xis xconverted xinto xheat xenergy xsome xlight xenergy xis
xreflected x
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describe xthe xnitrogen xcycle. x- x xcorrect xanswer. x x xfixation: xatmospheric
xnitrogen xcan xbe xfixed xby xrhizbium xbacteria. xif xstruck xby xlightning, xit xbecomes
xreactive xand xcombines xwith xoxygen xto xform xNO. x
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ammonification: x
saprobionts xfeed xon xorganic xmatter xand xrelease xammonia, xwhich xthen xforms
xammonium xions xin xthe xsoil. x x
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AQA biology a-level paper 2 questions and
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answers latest top score.
x x x x x
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x
x
x
describe xand xexplain xthe xsteps xin xthe xlight xdependent xreaction xof xphotosynthesis x- x
xcorrect xanswer. x x x1. xphotoionisation: xlight xreaches xchlorophyll xin xPSII, xwhich xis
xabsorbed xby xan xelectron, xwhich xbecomes xexcited xand xmoves xto xa xhigher xenergy
xlevel. x
2. the xelectron xpasses xto xa xcarrier xprotein xin xthe xthylakoid xmembrane, xand xis
xpassed xdown xa xseries xof xcarrier xmolecules xcalled xan xelectron xtransfer xchain. x
3. as xthe xelectron xmoves xdown, xenergy xis xlost xfrom xthe xelectron xand xis xreleased
xas xATP. x4. xthe xloss xof xelectron xfrom xPSII xis x'refilled' xby xan xelectron xproduced xby
xphotolysis, xwhich xalso xproduces xhydrogen xand xoxygen. x
5. the xlost xelectron xreaches xPSI, xwhich xabsorbs xlight xenergy xand xboosts xanother
xelectron xto xa xhigher xenergy xlevel x(excitation). x
6. this xelectron xalso xgoes xdown xan xelectron xtransport xchain. x
7. this xreaches xthe xfinal xelectron xacceptor xwhich xis xa xproton. xthey xcombine xto xform
xH xand xreduce xNADP xto xNADPH. x
x
describe xand xexplain xthe xsteps xin xthe xlight xindependent xreaction xpf xphotosynthesis. x-
x xcorrect xanswer. x x x1. xCO2 xdiffuses xinto xstroma xand xcombines xwith xribulose
xbisphosphate x(RuBP) xusing xthe xenzyme xrubisco. x
2. this xforms xan xunstable x6 xcarbon xmolecule, xwhich xsplits xinto x2 x3 xcarbon
xmolecules, xglyercate-3-phosphate x(G3P) x. x
3. G3P xis xreduced xby xNADPH xto xtriose-phosphate x(TP), xwhich xis xaided xby xATP xfor
xenergy. x x
4. TP xcan xbe xconverted xinto xuseful xorganic xsubstances. x
5. TP xcan xalso xbe xreformed xinto xRuBP xusing xATP. x
x
describe xglycolysis xin xrespiration. xgive xnet xformation. x- x xcorrect xanswer. x x x1. xglucose
xis xconverted xinto xphosphorylated xglucose xby x2ATP. xthis xmakes xit xvery xreactive, xso xit
xsplits xinto x2 xtriose xphosphate x(TP). x x
2. 2TP xis xthen xoxidised xby x2NAD xand x4 xATP xis xformed xto xform xpyruvate. x
, 3. NET: x2ATP, x2Pyruvate, x2NADH, x2H+ x
x
describe xlinks xreaction xin xrespiration. xgive xnet xformation. x- x xcorrect xanswer. x x x1.
xpyruvate xdiffuses xinto xthe xmatrix xof xmitochondria. x x
2. pyruvate xis xoxidised xby xNAD. xCO2 xis xlost. xthis xforms xacetate. x x
3. acetate xand xco-enzyme xA xcombine xto xform xacetyl xco-enzyme xA. x
4. NET: xCO2, xreduced xNAD, xacetyl xco-enzyme xA x
x
describe xkrebs xcycle xin xrespiration. xgive xnet xformation. x- x xcorrect xanswer. x x x1. xacetyl
xcoenzyme xA xcombines xwith x4 xcarbon xmolecule x(oxaloacetate) xto xform x6 xcarbon
xcitric xacid. x2. xCO2 xis xlost x(decarboxylation), xmolecule xis xoxidised xby xNAD xand xATP
xis xproduce. xthis xforms x5 xcarbon xcompound. x
3. it xis xoxidised xby x2NADH xand xFAD, xand xis xdecarboxylated. x
4. this xforms x4 xcarbon xmolecule xagain. x
x
describe xoxidative xphosphorylation xin xrespiration. x- x xcorrect xanswer. x x x1. xreduced
xcoenzyme xpasses xits xH xto xa xcarrier xprotein xin xthe xETC. xthis xsplits xinto xa xproton xand
xelectron. x
2. the xprotons xpass xthrough xthe xspace xbetween xinner xand xouter xmitochondrial
xmembrane. x
3. electrons xpass xthrough xproteins xon xETC. x
4. protons xreturn xback xvia xATP xsynthase xin xthe xmembrane, xproducing xATP. x
5. the xprotons xand xelectrons xrecombine xto xform xH, xwhich xcombines xwith xO xto xform
xwater. x
6. oxygen xis xthe xlast xelectron xacceptor xin xthe xETC. x
x
define xbiomass x- x xcorrect xanswer. x x xthe xtotal xmass xof xorganisms xin xa xgiven xarea x
x
what xis xthe x'gross xprimary xproduction' x- x xcorrect xanswer. x x xthe xchemical xenergy
xstored xin xa xplants xbiomass x
x
what xis xthe x'net xprimary xproduction' x- x xcorrect xanswer. x x xthe xchemical xenergy xstores
xin xa xplants xbiomass xafter xrespiratory xlosses xhave xbeen xconsidered. xthis xenergy xis
xavailable xto xconsumers. x
x
how xcan xyou xcalculate xthe xnet xprimary xproduction? x- x xcorrect xanswer. x x xNPP x= xGPP
x- xR xwhy xis xconverting xsunlight xenergy xinto xbiomass xin xproducers xinefficient? x- x
xcorrect xanswer. x x xsome xlight xisn't xthe xcorrect xwavelength xto xbe xabsorbed xsome xlight
xdoesnt xhit xchloroplast xsome xlight xis xconverted xinto xheat xenergy xsome xlight xenergy xis
xreflected x
x
describe xthe xnitrogen xcycle. x- x xcorrect xanswer. x x xfixation: xatmospheric
xnitrogen xcan xbe xfixed xby xrhizbium xbacteria. xif xstruck xby xlightning, xit xbecomes
xreactive xand xcombines xwith xoxygen xto xform xNO. x
x
ammonification: x
saprobionts xfeed xon xorganic xmatter xand xrelease xammonia, xwhich xthen xforms
xammonium xions xin xthe xsoil. x x
x
