Term
If we liken chemical equilibrium to the bottom of an energy hill, then an ________ reaction is an uphill run.
a.
endergonic
b.
exergonic
c.
ATP-assisted
d.
both a and c |
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Definition
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Term
Which statement is not correct? A metabolic pathway ________.
a.
has an orderly sequence of reaction steps
b.
is mediated by one enzyme, which initiates the reactions
c.
may be biosynthetic or degradative, overall
d.
all of the above |
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Definition
| is mediated by one enzyme, which initiates the reactions |
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Term
According to the first law of thermodynamics,
a.
although energy in the universe is constant, energy in an earthly system may increase.
b.
the amount of energy in the universe is constant.
c.
chemical reactions do not create or destroy energy.
d.
energy can change from one form to another.
e.
all of these |
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Definition
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Term
The second law of thermodynamics holds that
a.
matter can be neither created nor destroyed.
b.
energy can be neither created nor destroyed.
c.
energy of one form is converted to a less concentrated form whenever energy is transformed or transferred.
d.
entropy decreases with time.
e.
none of these |
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Definition
c.
energy of one form is converted to a less concentrated form whenever energy is transformed or transferred. |
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Term
Endergonic reactions
a.
have more energy in the reactants than in the products.
b.
have more energy in the products than in the reactants.
c.
are illustrated by the breakdown of glucose.
d.
are the mechanisms used by animals to provide energy for biological reactions.
e.
have more energy in the products than in the reactants and are illustrated by the breakdown of glucose. |
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Definition
| have more energy in the products than in the reactants. |
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Term
A "high-energy bond"
a.
absorbs a large amount of free energy when the phosphate group is attached during hydrolysis.
b.
is formed when ATP is hydrolyzed to ADP and one phosphate group.
c.
is usually found in each glucose molecule; that is why glucose is chosen as the starting point for glycolysis.
d.
releases a large amount of usable energy when the phosphate group is split off during hydrolysis.
e.
none of these |
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Definition
d.
releases a large amount of usable energy when the phosphate group is split off during hydrolysis. |
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Term
The removal of electrons from a compound is known as
a.
dehydration.
b.
oxidation.
c.
reduction.
d.
phosphorylation.
e.
a nonreversible chemical reaction. |
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Definition
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Term
When NAD+ combines with hydrogen, the NAD+ is
a.
reduced.
b.
oxidized.
c.
phosphorylated.
d.
denatured. |
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Definition
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Term
Which of the following statements is NOT true?
a.
At an equilibrium there are equal numbers of molecules on each side of a reaction.
b.
Chemical equilibrium is controlled solely by the amount of the reactants available.
c.
A chemical equilibrium is reached when the forward and reverse reactions occur at the same rate.
d.
At an equilibrium there are equal numbers of molecules on each side of a reaction; and Chemical equilibrium is controlled solely by the amount of the reactants available.
e.
At an equilibrium there are equal numbers of molecules on each side of a reaction; and Chemical equilibrium is controlled solely by the amount of the reactants available; and A chemical equilibrium is reached when the forward and reverse reactions occur at the same rate. |
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Definition
d.
At an equilibrium there are equal numbers of molecules on each side of a reaction; and Chemical equilibrium is controlled solely by the amount of the reactants available. |
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Term
A biosynthetic pathway can be characterized as
a.
endergonic.
b.
exergonic.
c.
degradative.
d.
releasing energy.
e.
producing ATP. |
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Definition
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Term
NAD+ and FAD are
a.
coenzymes.
b.
electron acceptors.
c.
reduced forms.
d.
coenzymes and electron acceptors.
e.
coenzymes, electron acceptors, and reduced forms. |
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Definition
| coenzymes and electron acceptors. |
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Term
Activation energy
a.
is less when enzymes are present.
b.
allows greater interaction of substrate with the active site.
c.
is needed to begin a reaction.
d.
is less when enzymes are present and is needed to begin a reaction.
e.
is less when enzymes are present, allows greater interaction of substrate with the active site, and is needed to begin a reaction. |
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Definition
| is less when enzymes are present, allows greater interaction of substrate with the active site, and is needed to begin a reaction. |
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Term
Which of the following is NOT a true statement?
a.
When an enzyme and a substrate fit together, they are in the "transition state."
b.
Most enzymes and substrates are exact fits, like a lock and key.
c.
Activation energy must be supplied before the "transition state" is reached.
d.
The idea for the lock-and-key theory was first proposed over 100 years ago.
e.
Enzymes have an active site where the substrate fits. |
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Definition
| Most enzymes and substrates are exact fits, like a lock and key. |
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Term
Inhibitors of enzyme-catalyzed reactions act by
a.
forming clusters of reactants that are unable to break free.
b.
tying up ATP supplies.
c.
binding to the enzyme's active site.
d.
tying up ATP supplies, and binding to the enzyme's active site.
e.
forming clusters of reactants that are unable to break free, tying up ATP supplies, and binding to the enzyme's active site. |
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Definition
| binding to the enzyme's active site. |
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Term
Allosteric inhibition is generally a result of
a.
excess substrates.
b.
binding of regulatory molecules at another site.
c.
a change in the temperature of the system.
d.
a lack of coenzymes.
e.
pH inhibition. |
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Definition
| binding of regulatory molecules at another site. |
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Term
An allosteric enzyme
a.
has an active site where substrate molecules bind and another site that binds with intermediate or end-product molecules.
b.
is an important energy-carrying nucleotide.
c.
carries out either oxidation reactions or reduction reactions but not both.
d.
raises the activation energy of the chemical reaction it catalyzes.
e.
all of these |
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Definition
| has an active site where substrate molecules bind and another site that binds with intermediate or end-product molecules. |
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Term
Which of the following is not a mechanism by which the binding energy can speed up a reaction?
a.
Helping substrates get together
b.
Inducing a change in the enzyme shape to prevent the binding of the substrate
c.
Orienting subtrates into positions favorable for a reaction.
d.
Shutting out water.
e.
Inducing a change in the enzyme shape to be complementary to the substrate. |
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Definition
| Inducing a change in the enzyme shape to prevent the binding of the substrate |
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