AQA BIOLOGY A-LEVEL PAPER
1 Exam Questions and Answers
100% PASS
Describe the induced fit model and how an enzyme acts as a catalyst (3)—
ANSWER-1.) Enzyme-substrate complex forms
2.)active site changes shape so it is complememtary to substrate (and to
break bonds in the substrate)
3.)Reduces activation energy
Suggest and explain a procedure the scientist could have used to stop
enzyme activity (2)—ANSWER-1.) Boil(or add strong acid/alkali)
2.)Denatures the enzyme
3.) put in ice
4.)lower kinetic energy so no enzyme-substrate complexes form
5.)Add high concentration of inhibitor
6.)Enzyme-substrate complexes do not form
, Explain the change in ATP concentration with increasing inorganic
phosphate concentration (3)—ANSWER-1.)With increasing Pi concentrations
more enzyme-substrate complexes are formed
2.) At or above 40(mol dm-3) all active sites are occupied
OR at or above 40 (mmol dm-3) enzyme concentration is a limiting factor
Explain the advantage for larger animals of having specialised system that
facilitates oxygen uptake (2)—ANSWER-1.) Larger organisms have a smaller
surface area to volume ratio
2.) overcomes loony diffusion pathway
OR faster diffusion
Suggest how the environmental conditions have resulted in adaptations of
systems using model A rather than model B (b inside (human lungs) and a
outside(fish) (2) mark in pairs—ANSWER-1.) Water has a lower oxygen
partial pressure/concentration (than air)
2.) So system in outside gives large surface area (in contact with water)
OR system on outside reduces diffusion distance(between water and blood)
3.) water is denser than air
4.) So water supports the systems/gills
A student studied figure 3 and concluded that the fish gas exchange is more
efficient than the human gas exchange system (2)—ANSWER-1.)In fish blood
leaving (V) has a more oxygen than water leaving (E)
© 2026 Copyright. All Rights Reserved. This document is
protected by copyright law, Copyrighted By Katelyn Whitman
1 Exam Questions and Answers
100% PASS
Describe the induced fit model and how an enzyme acts as a catalyst (3)—
ANSWER-1.) Enzyme-substrate complex forms
2.)active site changes shape so it is complememtary to substrate (and to
break bonds in the substrate)
3.)Reduces activation energy
Suggest and explain a procedure the scientist could have used to stop
enzyme activity (2)—ANSWER-1.) Boil(or add strong acid/alkali)
2.)Denatures the enzyme
3.) put in ice
4.)lower kinetic energy so no enzyme-substrate complexes form
5.)Add high concentration of inhibitor
6.)Enzyme-substrate complexes do not form
, Explain the change in ATP concentration with increasing inorganic
phosphate concentration (3)—ANSWER-1.)With increasing Pi concentrations
more enzyme-substrate complexes are formed
2.) At or above 40(mol dm-3) all active sites are occupied
OR at or above 40 (mmol dm-3) enzyme concentration is a limiting factor
Explain the advantage for larger animals of having specialised system that
facilitates oxygen uptake (2)—ANSWER-1.) Larger organisms have a smaller
surface area to volume ratio
2.) overcomes loony diffusion pathway
OR faster diffusion
Suggest how the environmental conditions have resulted in adaptations of
systems using model A rather than model B (b inside (human lungs) and a
outside(fish) (2) mark in pairs—ANSWER-1.) Water has a lower oxygen
partial pressure/concentration (than air)
2.) So system in outside gives large surface area (in contact with water)
OR system on outside reduces diffusion distance(between water and blood)
3.) water is denser than air
4.) So water supports the systems/gills
A student studied figure 3 and concluded that the fish gas exchange is more
efficient than the human gas exchange system (2)—ANSWER-1.)In fish blood
leaving (V) has a more oxygen than water leaving (E)
© 2026 Copyright. All Rights Reserved. This document is
protected by copyright law, Copyrighted By Katelyn Whitman
