AQA A-Level Biology - Enzymes

AQA A-Level Biology - Enzymes 1. Activation Energy - The minimum energy required for successful collisions to result in a reaction 2. Enzyme Function - Lowers the activation energy for a reaction to start, behaves as a catalyst 3. Enzyme Structure - Globular proteins that have a functional region known as an active site 4. Active Site - Functional region on an enzyme that is complimentary to substrates 5. Complimentary - Of a similar shape to one another 6. Induced Fit Model - 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 7. Lock and Key Theory - 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 8. Factors affecting Enzyme Action - temperature, pH, concentration of enzyme/substrate 9. How Temperature affects Enzyme Action - 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 10. How pH affects Enzyme Action - Further from optimum causes reversible denaturing but prevents formation of ES complexes. Closer to optimum increases the formation of ES complexes 11. How Concentration affects Enzyme Action - Low concentration has excess substrate molecules so enzymes work at an optimum. Medium concentration results in optimum working as all substrates occupy all active sites. High concentration has excess enzyme so not all enzymes work at an optimum.