AQA A-LEVEL BIOLOGY - ENZYMES
REVISION PAPER 2023 WITH CORRECT
QUESTIONS AND ANSWERS
Activation Energy (Correct Answers) The minimum energy required for successful
collisions to result in a reaction
Enzyme Function (Correct Answers) Lowers the activation energy for a reaction to start,
behaves as a catalyst
Enzyme Structure (Correct Answers) Globular proteins that have a functional region
known as an active site
Active Site (Correct Answers) Functional region on an enzyme that is complimentary to
substrates
Complimentary (Correct Answers) Of a similar shape to one another
Induced Fit Model (Correct Answers) The way by which an enzyme alters the shape of
its active site to be exactly complimentary with a substrate to form an enzyme-substrate
complex
Lock and Key Theory (Correct Answers) Older theory suggesting that enzymes have a
fixed shape active site that is always complimentary to specific substrates, rather than
having an adjustable shaped active site
Factors affecting Enzyme Action (Correct Answers) temperature, pH, concentration of
enzyme/substrate
How Temperature affects Enzyme Action (Correct Answers) Low temperature has few
ES complexes. Medium temperature has an increase in ES complexes. Optimum
temperature has maximum rate of ES complex formation. Above optimum denatures the
enzyme which decreases ES complexes
How pH affects Enzyme Action (Correct Answers) Further from optimum causes
reversible denaturing but prevents formation of ES complexes. Closer to optimum
increases the formation of ES complexes
REVISION PAPER 2023 WITH CORRECT
QUESTIONS AND ANSWERS
Activation Energy (Correct Answers) The minimum energy required for successful
collisions to result in a reaction
Enzyme Function (Correct Answers) Lowers the activation energy for a reaction to start,
behaves as a catalyst
Enzyme Structure (Correct Answers) Globular proteins that have a functional region
known as an active site
Active Site (Correct Answers) Functional region on an enzyme that is complimentary to
substrates
Complimentary (Correct Answers) Of a similar shape to one another
Induced Fit Model (Correct Answers) The way by which an enzyme alters the shape of
its active site to be exactly complimentary with a substrate to form an enzyme-substrate
complex
Lock and Key Theory (Correct Answers) Older theory suggesting that enzymes have a
fixed shape active site that is always complimentary to specific substrates, rather than
having an adjustable shaped active site
Factors affecting Enzyme Action (Correct Answers) temperature, pH, concentration of
enzyme/substrate
How Temperature affects Enzyme Action (Correct Answers) Low temperature has few
ES complexes. Medium temperature has an increase in ES complexes. Optimum
temperature has maximum rate of ES complex formation. Above optimum denatures the
enzyme which decreases ES complexes
How pH affects Enzyme Action (Correct Answers) Further from optimum causes
reversible denaturing but prevents formation of ES complexes. Closer to optimum
increases the formation of ES complexes
