AQA A LEVEL BIOLOGY PAPER 2 LATEST 2025 WITH
QUESTIONS AND WELL DETAILED ANSWERS GRADED
A+|| LATEST UPDATE 2025/26
air spaces between them = rapid diffusion, long and narrow and are packed with
chloroplast the thin tissue of the leaf allows light to reach mesophyll -
CORRECTANSWER Name three advantages of mesophyll in the leaf
stroma in the fluid filled matrix -CORRECTANSWER where does the LIR occur?
100 stacked discs of thylakoids -CORRECTANSWER what is the grana?
chlorophyll absorbs light energy, excite electrons, move along carriers etc releasing
energy, used to join ADP and pi to form ATP, photolysis of water produces protons
electrons oxygen, NADP reduced by electrons -CORRECTANSWER describe the light
dependent reaction starting with Photolysis
electron is oxidised that reduces NADP, carries out series of redox reactions along the
electron transport chain that is then accepted by oxygen that is the terminal electron
receptor which oxidises NADPH back to NADP -CORRECTANSWER describe the
electron transport chain
contain both DNA and RNA so proteins can be manufactured quickly, thylakoid
membrane has a large SA for rapid DF and a network of proteins in the Grana to
,maximise the absorbance of light -CORRECTANSWER name three advantages of the
structure of a chloraplast
CO2 combines 5 carbon ribulose-bi-phosphate to make 6 carbon molecule that is then
catalysed by rubisco to create two 3 phosphate glycerate molecules that are then
reduced via NADP and energy from ATP from LDR to triose phosphate that will
eventually turn into glucose, NADP reformed and goes back to LDR -
CORRECTANSWER describe the process of the LIR
phosphorylated glucose is broken down in two 3 carbon molecules called pyruvate
(happens in the matrix mitochondria -CORRECTANSWER what is glycolysis and where
does it happen?
pyruvate is decarboxylated and dehydrogenated to acetate NAD is reduced -
CORRECTANSWER what happens in the link reaction after Glycolysis?
acetyl coenzyme A combines with oxaloacetate to form citrate which is decarboxylated
and dehydrogenated to form 5 carbon molecule which is then dehydrogenated and
decarboxylated to form 4 carbon ATP made by substrate-level phosphorylation and
FAD is reduced, oxalacetate is then regenerated to restart the cycle -
CORRECTANSWER what happens in the Krebs Cycle after the link reaction?
, H+ from oxidized reduced NAD and FAD, splits into p and e travels down electron
transport chain via oxidation-reduction reactions losing energy each carrier used pump
p from matrix into intermembrane space creating high concentration forming
electrochemical gradient move down into matrix by ATP synthase drives synthesis ATP
chemiosmosis, Matriz end transport chain p,e, and o combine form water. o final
electron acceptor. -CORRECTANSWER what is oxidative phosphorylation?
hydrolysed to glycerol that is phosphorylated into into triose phosphate that becomes
glucose and thus glycolysis can occur -CORRECTANSWER how does the respiration
of lipids occur?
where no oxygen is available to accept the H+ ion and so reduced NAD builds up and
cannot take anymore H+ from Glyolysis thus pyruvate is now reduced and produces
lactate and oxdidised NAD and produces ethanol in plants -CORRECTANSWER what
is anaerobic respiration?
the dry weight of the total mass of living material in a specific area at a given time -
CORRECTANSWER what is biomass?
gross primary production - respiratory losses = the chemical energy left -
CORRECTANSWER what is the calculation for net primary production? and what is it?
total chemical plant biomass -CORRECTANSWER what is gross primary production?
QUESTIONS AND WELL DETAILED ANSWERS GRADED
A+|| LATEST UPDATE 2025/26
air spaces between them = rapid diffusion, long and narrow and are packed with
chloroplast the thin tissue of the leaf allows light to reach mesophyll -
CORRECTANSWER Name three advantages of mesophyll in the leaf
stroma in the fluid filled matrix -CORRECTANSWER where does the LIR occur?
100 stacked discs of thylakoids -CORRECTANSWER what is the grana?
chlorophyll absorbs light energy, excite electrons, move along carriers etc releasing
energy, used to join ADP and pi to form ATP, photolysis of water produces protons
electrons oxygen, NADP reduced by electrons -CORRECTANSWER describe the light
dependent reaction starting with Photolysis
electron is oxidised that reduces NADP, carries out series of redox reactions along the
electron transport chain that is then accepted by oxygen that is the terminal electron
receptor which oxidises NADPH back to NADP -CORRECTANSWER describe the
electron transport chain
contain both DNA and RNA so proteins can be manufactured quickly, thylakoid
membrane has a large SA for rapid DF and a network of proteins in the Grana to
,maximise the absorbance of light -CORRECTANSWER name three advantages of the
structure of a chloraplast
CO2 combines 5 carbon ribulose-bi-phosphate to make 6 carbon molecule that is then
catalysed by rubisco to create two 3 phosphate glycerate molecules that are then
reduced via NADP and energy from ATP from LDR to triose phosphate that will
eventually turn into glucose, NADP reformed and goes back to LDR -
CORRECTANSWER describe the process of the LIR
phosphorylated glucose is broken down in two 3 carbon molecules called pyruvate
(happens in the matrix mitochondria -CORRECTANSWER what is glycolysis and where
does it happen?
pyruvate is decarboxylated and dehydrogenated to acetate NAD is reduced -
CORRECTANSWER what happens in the link reaction after Glycolysis?
acetyl coenzyme A combines with oxaloacetate to form citrate which is decarboxylated
and dehydrogenated to form 5 carbon molecule which is then dehydrogenated and
decarboxylated to form 4 carbon ATP made by substrate-level phosphorylation and
FAD is reduced, oxalacetate is then regenerated to restart the cycle -
CORRECTANSWER what happens in the Krebs Cycle after the link reaction?
, H+ from oxidized reduced NAD and FAD, splits into p and e travels down electron
transport chain via oxidation-reduction reactions losing energy each carrier used pump
p from matrix into intermembrane space creating high concentration forming
electrochemical gradient move down into matrix by ATP synthase drives synthesis ATP
chemiosmosis, Matriz end transport chain p,e, and o combine form water. o final
electron acceptor. -CORRECTANSWER what is oxidative phosphorylation?
hydrolysed to glycerol that is phosphorylated into into triose phosphate that becomes
glucose and thus glycolysis can occur -CORRECTANSWER how does the respiration
of lipids occur?
where no oxygen is available to accept the H+ ion and so reduced NAD builds up and
cannot take anymore H+ from Glyolysis thus pyruvate is now reduced and produces
lactate and oxdidised NAD and produces ethanol in plants -CORRECTANSWER what
is anaerobic respiration?
the dry weight of the total mass of living material in a specific area at a given time -
CORRECTANSWER what is biomass?
gross primary production - respiratory losses = the chemical energy left -
CORRECTANSWER what is the calculation for net primary production? and what is it?
total chemical plant biomass -CORRECTANSWER what is gross primary production?
