AP Biology : Understand different models of enzyme function

Study concepts, example questions & explanations for AP Biology

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Example Questions

Example Question #1 : Understand Different Models Of Enzyme Function

The induced fit model better explains enzyme substrate binding than does the lock and key model. The induced fit model explains which of the following, that is not explained by the lock and key model

Possible Answers:

Rigid structure of enzymes

Rigid structure of substrate

Narrow specificity of enzymes

Broad specificity of enzymes

Correct answer:

Broad specificity of enzymes

Explanation:

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 accounts for the broad specificity of enzymes as the active site is not rigid, but can undergo a conformational change to better fit the substrate binding.

Example Question #2 : Understand Different Models Of Enzyme Function

This model of enzyme and substrate interaction posits that the active site of the enzyme undergoes conformational change when the correct substrate binds

Possible Answers:

Lock and key model

Enzyme substrate model

Conformation model

Induced fit

Correct answer:

Induced fit

Explanation:

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.

Example Question #3 : Understand Different Models Of Enzyme Function

The lock and key model of enzyme substrate binding posits that

Possible Answers:

The active site of the enzyme undergoes conformational change when the substrate binds

There is broad specificity of enzymes

Enzymes cannot be reused

The enzyme and substrate have complementary geometric shapes and are specific to one another

Correct answer:

The enzyme and substrate have complementary geometric shapes and are specific to one another

Explanation:

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.

Example Question #4 : Understand Different Models Of Enzyme Function

Which model of enzyme substrate binding posits that there is a transition state that develops before the reactants undergo change

Possible Answers:

Induced fit

Catalysis

Conformational change

Lock and key

Correct answer:

Induced fit

Explanation:

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.

Example Question #5 : Understand Different Models Of Enzyme Function

Which is NOT true of the lock and key model of enzyme substrate bonding?

Possible Answers:

The active site fits perfectly with the substrate

 

The active site is static

The enzyme does not have a separate catalytic group

There is a transition state during which the shape of the active site changes to better fit the substrate

Correct answer:

There is a transition state during which the shape of the active site changes to better fit the substrate

Explanation:

 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 #6 : Understand Different Models Of Enzyme Function

How do enzymes speed up a reaction?

Possible Answers:

Decrease yield of reaction

Stabilization of transition state, lowering activation energy

Increase enthalpy of reaction

Stabilization of transition state, increasing activation energy

Correct answer:

Stabilization of transition state, lowering activation energy

Explanation:

 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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