2023 AQA A-level BIOLOGY 7402/1 Paper 1 With Mark
Scheme(Merged) Latest Exam
Describezthezrolezofzazribosomezinzthezproductionzofzazpolypeptide.z/3z-zCORRECTzANSWER-
1.zmRNAzbindsztozribosome;
2.zIdeazofzTWOzcodons/bindingzsites;
3.ztRNAzwithzANTICODONSzbinds;
4.z(Catalyses)zformationzofzPEPTIDEzbondzbetweenzAMINOzACIDSz(heldzbyztRNAzmolecules);
5.zMoveszalongz(mRNAztoztheznext
codon);
Describezthezstructurezofzglycogen.z/2z-zCORRECTzANSWER-1.zPolysaccharidezofzα-glucose;
OR
polymerzofzα-glucose;
2.z(Joinedzby)zglycosidiczbonds
z OR
Branchedzstructure;
NHE3zactivelyztransportszonezsodiumzionzintozthezcellzinzexchangezforzonezproton
(hydrogenzion)zoutzofzthezcell.
UsezyourzknowledgezofztransportzacrosszcellzmembranesztozsuggestzhowzNHE3
doeszthis.z/3z-zCORRECTzANSWER-1.zCo-transport;
2.zUsesz(hydrolysiszof)zATP;
3.zSodiumzionzandzprotonzbindztozthezprotein;
4.zProteinzchangeszshapez(tozmovezsodiumzion
and/orzprotonzacrosszthezmembrane);
Explainzthezcurveszforzmaxzproteasezactivityzoverztimezatz50Czandz60C.z/4z-zCORRECTzANSWER-
1.zBothzdenaturedz(byzhighztemperature);
2.zDenaturationzfasterzatz60z°Czdueztozmorez(kinetic)zenergy;
, 3.zBreakszhydrogen/ioniczbondsz(betweenzaminozacids/Rzgroups);
4.zChangezinzshapezofzthezactivezsite/activezsiteznozlongerzcomplementaryzsozfewerzenzyme-
substratezcomplexeszformed;
Describezthezactionzofzthesezmembrane-boundzdipeptidaseszandzexplainztheir
importance.z/2z-zCORRECTzANSWER-1.zHydrolysez(peptidezbonds)ztozreleasezaminozacids;
2.zAminozacidszcanzcrossz(cell)zmembrane;
OR
Dipeptideszcannotzcrossz(cell)zmembrane;
OR
Maintainzconcentrationzgradientzofzaminozacidszforzabsorption;
Explainzwhyzthezscientistszsuggestedzthatzpatientszshouldzbeztreatedzwithzbothzthezcurrentzantibioticzandz
theznewzone.
UsezinformationzfromzFigurez2z(oldzantibioticzdecreasesznumberzofzbacteria,znewzonezdecreaseszitzmore)z
andzyourzknowledgezofzevolutionzofzantibioticzresistancezinzbacteriazinzyourzanswer.z/3z-
zCORRECTzANSWER-1.z(FromzFigz2)zNew/oldzantibioticzdoesznotzkillzallzbacteria;
OR
(FromzFigz2)zSomezbacteriazarezresistantztoztheznew/oldzantibiotic;
2.zResistantzbacteriazwillzreproduceztozproducez(more)zresistantzbacteria;
3.z(Usezofzboth)zonezantibioticzwillzkillzbacteriazresistantztozthezotherzantibiotic;
OR
Unlikelyzthatzbacteriazarezresistantztozbothztheznewzandzthezoldzantibiotic;
OR
Usezofzbothzantibioticsz(likelyzto)zkillzall/mostzbacteria;
Whenzmeasuringzthezleakinesszofzherbicide-
treatedzcellzmembranesztozions,zwhyzdidzthezscientistszgentlyzshakezthezflaskszcontainingzthezleafzdiscs?z/1
z-zCORRECTzANSWER-(Shaking)zSozallzsurfaceszofzthezleafzdiscszarezexposedz(tozwater)/sozallzsubmerged;
OR
Scheme(Merged) Latest Exam
Describezthezrolezofzazribosomezinzthezproductionzofzazpolypeptide.z/3z-zCORRECTzANSWER-
1.zmRNAzbindsztozribosome;
2.zIdeazofzTWOzcodons/bindingzsites;
3.ztRNAzwithzANTICODONSzbinds;
4.z(Catalyses)zformationzofzPEPTIDEzbondzbetweenzAMINOzACIDSz(heldzbyztRNAzmolecules);
5.zMoveszalongz(mRNAztoztheznext
codon);
Describezthezstructurezofzglycogen.z/2z-zCORRECTzANSWER-1.zPolysaccharidezofzα-glucose;
OR
polymerzofzα-glucose;
2.z(Joinedzby)zglycosidiczbonds
z OR
Branchedzstructure;
NHE3zactivelyztransportszonezsodiumzionzintozthezcellzinzexchangezforzonezproton
(hydrogenzion)zoutzofzthezcell.
UsezyourzknowledgezofztransportzacrosszcellzmembranesztozsuggestzhowzNHE3
doeszthis.z/3z-zCORRECTzANSWER-1.zCo-transport;
2.zUsesz(hydrolysiszof)zATP;
3.zSodiumzionzandzprotonzbindztozthezprotein;
4.zProteinzchangeszshapez(tozmovezsodiumzion
and/orzprotonzacrosszthezmembrane);
Explainzthezcurveszforzmaxzproteasezactivityzoverztimezatz50Czandz60C.z/4z-zCORRECTzANSWER-
1.zBothzdenaturedz(byzhighztemperature);
2.zDenaturationzfasterzatz60z°Czdueztozmorez(kinetic)zenergy;
, 3.zBreakszhydrogen/ioniczbondsz(betweenzaminozacids/Rzgroups);
4.zChangezinzshapezofzthezactivezsite/activezsiteznozlongerzcomplementaryzsozfewerzenzyme-
substratezcomplexeszformed;
Describezthezactionzofzthesezmembrane-boundzdipeptidaseszandzexplainztheir
importance.z/2z-zCORRECTzANSWER-1.zHydrolysez(peptidezbonds)ztozreleasezaminozacids;
2.zAminozacidszcanzcrossz(cell)zmembrane;
OR
Dipeptideszcannotzcrossz(cell)zmembrane;
OR
Maintainzconcentrationzgradientzofzaminozacidszforzabsorption;
Explainzwhyzthezscientistszsuggestedzthatzpatientszshouldzbeztreatedzwithzbothzthezcurrentzantibioticzandz
theznewzone.
UsezinformationzfromzFigurez2z(oldzantibioticzdecreasesznumberzofzbacteria,znewzonezdecreaseszitzmore)z
andzyourzknowledgezofzevolutionzofzantibioticzresistancezinzbacteriazinzyourzanswer.z/3z-
zCORRECTzANSWER-1.z(FromzFigz2)zNew/oldzantibioticzdoesznotzkillzallzbacteria;
OR
(FromzFigz2)zSomezbacteriazarezresistantztoztheznew/oldzantibiotic;
2.zResistantzbacteriazwillzreproduceztozproducez(more)zresistantzbacteria;
3.z(Usezofzboth)zonezantibioticzwillzkillzbacteriazresistantztozthezotherzantibiotic;
OR
Unlikelyzthatzbacteriazarezresistantztozbothztheznewzandzthezoldzantibiotic;
OR
Usezofzbothzantibioticsz(likelyzto)zkillzall/mostzbacteria;
Whenzmeasuringzthezleakinesszofzherbicide-
treatedzcellzmembranesztozions,zwhyzdidzthezscientistszgentlyzshakezthezflaskszcontainingzthezleafzdiscs?z/1
z-zCORRECTzANSWER-(Shaking)zSozallzsurfaceszofzthezleafzdiscszarezexposedz(tozwater)/sozallzsubmerged;
OR
