28 Questions
What is the main way enzymes reduce the activation energy?
By stabilising the transition state
Which model states that the enzyme's active site is exactly the correct shape for the substrate to bind to?
Lock and key model
What is the point of highest energy on the progress of a reaction curve called?
Transition state
Which type of reaction do most enzymes catalyze?
One type of reaction
What does the induced fit model propose?
Substrate induces a change in confirmation
What ratio is used to obtain rate enhancement?
Kcat/Kun
What occurs at the point of highest energy on the progress of a reaction curve?
Bond breakage and formation
What do enzymes primarily catalyse?
Reactions with high activation energy
What does substrate specificity refer to?
An enzyme's ability to bind only one optical isomer
What type of model suggests that small molecules with a similar shape to part of the substrate cannot bind?
Lock and key model
Which type of inhibitor forms covalent interactions with the enzyme and does not come off once it binds?
Irreversible inhibitor
In which process does a molecule become irreversibly bound and inactivate the enzyme?
Suicide inhibition
What is the measure of affinity between enzyme and inhibitor in competitive inhibition?
Ki
Which type of inhibitor binds at the same site as the substrate and blocks access for the substrate?
Competitive inhibitor
Which type of inhibitor induces a conformational change in the enzyme and prevents catalysis?
Non-competitive inhibitor
Which plot can be used to distinguish between competitive and non-competitive inhibitors?
Lineweaver-Burk plot
Which molecule is an example of a suicide inhibitor?
5-fluorouracil
Which enzyme is methotrexate a competitive inhibitor for?
Dihydrofolate reductase
Enzymes are generally smaller than their substrates.
False
The lock and key model suggests that small molecules with a similar shape to part of the substrate cannot bind.
True
Enzymes can catalyze multiple types of reactions.
True
The induced fit model proposes that the substrate induces a change in confirmation so it can fit into the active site of the enzyme.
True
The main way enzymes reduce the activation energy is by increasing the energy of the transition state.
False
Non-competitive inhibitors do not affect the Vmax of an enzyme
False
Sarin is an example of a reversible inhibitor of acetylcholinesterase
False
Reversible inhibitors can be removed from the enzyme by dialysis due to covalent interactions
False
Methotrexate is a non-competitive inhibitor for the enzyme dihydrofolate reductase
False
The Lineweaver-Burk plot can be used to distinguish between competitive and non-competitive inhibitors
True
Test your knowledge of enzyme-substrate complexes and enzyme models with this quiz. Learn about the lock and key model, active sites, and the specificity of enzyme catalysis.
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