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Example Question #42 : Enzymes
Which is NOT true of the lock and key model of enzyme substrate bonding?
There is a transition state during which the shape of the active site changes to better fit the substrate
The active site fits perfectly with the substrate
The enzyme does not have a separate catalytic group
The active site is static
There is a transition state during which the shape of the active site changes to better fit the substrate
The lock and key model states that the active site of an enzyme precisely fits a specific substrate. The induced fit model states that the active site of an enzyme will undergo a conformational change when binding a substrate, to improve the fit. The induced fit model does not account for a transition state during which the shape of the active site changes to better fit the substrate.
Example Question #43 : Enzymes
How do enzymes speed up a reaction?
Increase enthalpy of reaction
Stabilization of transition state, increasing activation energy
Decrease yield of reaction
Stabilization of transition state, lowering activation energy
Stabilization of transition state, lowering activation energy
Enzymes speed up reactions through lowering the activation energy, of the energy needed to break bonds of reactants. The activation energy is lowered through stabilizing the transition state; the active site of the enzyme better fits the substrate, allowing bonds to more readily be broken, requiring less energy.
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