WorksheetsKMJ SB025 RBC TOPIC 4 : BIOCATALYSIS
Total questions: 15
Worksheet time: 15mins
Enzymes
Bind their substrates at active sites
Can bind to cofactors such as metal ions that participate in enzyme reactions
Are composed primarily of polypeptides, which are polymers of amino acids
All statements are true
Enzymes function as catalysts because they
Increase the free energy of a chemical reaction
Lower the activation energy of a chemical reaction
Decrease the enthalpy of a chemical reaction
Supply the energy to start a chemical reaction
In the lock and key hypothesis, the lock is
The enzyme
The substrate
The enzyme-substrate complex
The enzyme-product complex
Cofactors for enzyme are
The protein substance
The inorganic substance
The protein and non-protein substances
The non-protein substance
Which is true of non-competitive inhibition?
It is irreversible
The inhibitor binds only to the active site of enzyme
The inhibitor binds to enzyme to lower activation energy
It can be reduced by increasing the concentration of the substrate
Which of the following is/are irreversible?
Competitive inhibition
Non competitive inhibition
Allosteric inhibition
None of these
An enzyme increases the rate of reaction by
Shifting the position of equilibrium of the reaction
Increasing the rate of random collisions of molecules
Lowering the energy of activation
Supplying the energy required to start the reaction
How does an enzyme increase the rate of reaction?
By shifting the equilibrium point of reaction
By supplying the energy required to start the reaction
By increasing the rate of random collision of molecules
By bringing the reactant molecules to the correct orientation
What happens to an enzyme when it is denatured?
The activation energy is doubled
The activation energy is lowered
The optimal temperature for enzyme action is doubled
The shape of the enzyme molecule is change
Which type of reversible enzyme inhibitor binds to both the free enzyme and the enzyme-substrate complex?
Non-competitive inhibitor
Competitive inhibitor
End product inhibitor
None of the above
In non-competitive inhibitor, the allosteric inhibitor
Binds to the active site, preventing the substrate from binding to the enzyme
Binds to the substrate, preventing it from binding to the active site
Binds to the enzyme at a site away from the active site, altering the shape of the enzyme
Changes the pH of the environment that the enzyme acts in
Which class of enzyme catalyses the formation of bonds between two molecules using energy derived from the hydrolysis of ATP?
Oxidoreductases
Hydrolases
Ligases
Transferases
Transferases are enzymes that
Split chemical bonds by hydrolysis
Catalyse the transfer of an atom or group of atoms from one substrate to another
Rearrange atoms in a substrate
Form bonds with cleavage of ATP
Increasing the substrate concentration in an enzymatic reaction could overcome which of the following?
Allosteric inhibition
Insufficient cofactors
Competitive inhibition
Denaturation of the enzyme
Malonic acid could inhibit the action of succinic dehydrogenase on succinic acid because
Malonic acid could react with succinic acid
Malonic acid could bind at the active site of succinic dehydrogenase
Succinic acid could bind at the active site of succinic dehydrogenase
Succinic acid could not bind at the active site of succinic dehydrogenase
