Explore how substrate binding reshapes both enzyme and substrate, aligning catalytic groups so the substrate moves towards the transition state in IB Biology HL C1.1.5.
Describe the lock and key model of enzyme activity and how the induced fit model extends it.
enzymes are (globular) proteins that are catalysts/lower activation energy of chemical reactions;
lock and key model:
explains specificity of enzyme-substrate;
the substrate (key) fits into/has complementary shape to the active site (lock) of the enzyme;
the active site can be changed by different chemicals/temperatures/pH so substrate cannot bind;
induced-fit model:
changes in the active site/conformational changes to allow substrate to bind;
the substrate induces the active site to change;
bonds weakened in the substrate (so easier to break);
explain reduction of activation energy/wider substrate specificity;
Award [3 max] if only one model addressed.