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WorksheetsEnzymes
Total questions: 12
Worksheet time: 6mins
Which of the following is TRUE regarding cofactors?
Coenzymes are often separate from the enzyme and do not need recharged.
Metal ions must be covalently attached to function as a cofactor.
Cofactor is a broad term used for all enzyme "helpers".
Prosthetic groups can dissociate readily and be regenerated for use in another enzyme.
An apoenzyme implies that a cofactor is present.
Proton transfer from an acid, lowering the free energy of a reaction’s transition state, is characteristic of
electrostatic catalysis.
nucleophilic catalysis.
general base catalysis.
general acid catalysis.
concerted acid-base catalysis.
Which of the following processes would yield and increase in rate?
the proximity of the reacting groups
the rotational motions of the substrates and catalytic groups
the orientations of the substrates and catalytic groups
all of the above
none of the above
Enzyme X catalyzes the addition of a hydroxyl group to substrate Y. In the process a metal cofactor is reduced and then reoxidized. What class of enzyme is X?
oxidoreductase
ligase
hydrolase
isomerase
lyase
The transition state of an enzyme and substrate reaction
must always bind the enzyme active site with lower energy than the products.
is stabilized by enhancing the reverse reaction of E + S→ES.
is composed of true covalent bonds which decrease its energy.
is stabilized due to the specificity of the active site for the substrate.
is stabilized by decreasing the effective concentration.
Research scientists are trying to clone a gene. In order to accomplish this task they join two pieces of DNA. Which class of the enzymes below might accomplish this task?
oxidoredutase
ligase
hydrolase
isomerase
lyase
The enzyme pictured above is shown in two configurations, A (open) and B (closed). Upon binding substrate in the active site, the enzyme converts the structure shown in B. Which of the following is true based on the given information?
The enzyme requires a high concentration of substrate to function.
This example exemplifies the “lock-and-key” model.
This enzyme must require ATP.
This example exemplifies the of “induced fit” model.
None of these are true.
The ability for an enzyme to change its shape upon substrate binding represents the concept of
lock and key.
induced fit.
proximity and orientation effects.
covalent catalysis.
none of the above
The highest point in a reaction coordinate diagram represents
an intermediate of the reaction pathway.
the reactants in an exergonic reaction.
the products in an endergonic reaction.
the transition state.
the overall delta G for the reaction.
How does a catalyst increase the rate of a reaction?
It makes the reaction more exergonic.
It increases the temperature of the reaction.
It allows reacting molecules to more easily form the transition state.
It causes a localized increase in the concentration of the reactants.
none of the above
When a substrate and enzyme interact, the first chemical species formed is the
enzyme-substrate complex.
enzyme-transition state complex.
enzyme-product complex.
enzyme plus product.
none of the above.
If you add enzymes to a solution containing only the product(s) of a reaction, would you expect any substrate to form?
It depends on the time interval and temperature of reaction.
It depends on the concentration of products added.
It depends on the energy difference between E + P and the transition state.
All of the above may determine if product forms.
None of the above determines if product forms.
