Enzyme Reaction
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Oxidation
is the __________.
a. loss
of proton
b. gain
of electron
c.
loss of electron
d. gain
of protons
Denaturation
of an enzyme refers to the __________.
a.
improper arrangement of the enzyme in a metabolic pathway
b.
loss of the enzymes proper shape
c.
formation of the enzymes proper shape
d.
formation of a new isozyme for that enzyme
An
exergonic reaction is one that __________.
a.
requires energy to proceed
b.
releases energy for work
c.
gives off much heat
d.
looses energy
If
the free energy change (ΔG) in a reaction is a negative value, it indicates
that the __________.
a.
reaction releases energy
b.
reaction absorbs energy
c.
reaction is in negative direction
d.
reaction is in positive direction
In
the reaction, C6H12O6+ 6O2 → 6CO2 + 6H2O + energy, which component is being
oxidized?
a.
C6H12O6
b. O2
c.
CO2
d. H2O
The
fact that β-oxidation of fatty acids, occurs in the mitochondria whereas fatty
acid synthesis occurs in the cytoplasmic matrix, is an example of regulation of
enzymatic activity by the __________ mechanism.
a.
compartmentation
b.
induction
c.
competitive inhibition
d.
repression
Reduction
is the __________.
a. loss
of proton
b.
gain of electron
c. loss
of electron
d. gain
of protons
If
the Keq for an enzymatic reaction is greater than 1, the reaction __________.
a. will
be endergonic
b. can
not occur without the input of energy
c. both
(a) and (b)
d.
none of these
The
ability of Vibrio fischeri to convert chemical energy directly into radiant
energy in bioluminescence is an example of __________ at work.
a.
Shelford's law of tolerance
b.
Leibig's law of the minimum
c.
the first law of thermodynamics
d. the
third law of thermodynamics
The
ability of a competitive inhibitor to bind to an active site in an
allosterically controlled enzyme is __________ than the ability of a
non-competitive inhibitor to bind to an active site in the same allosterically
controlled enzyme.
a.
greater
b.
lesser
c.
approximately equal
d. half
To
a living organism, which of the following has the greatest amount of available
energy per molecule?
a.
ATP
b. ADP
c.
AMP
d. H2O
Which
of the following is the best evidence for the lock and key theory of enzyme
action?
a.
Compounds similar in structure to the substrate inhibit enzyme activity
b.
Enzymes are found in living organisms and speed up certain reactions
c.
Enzymes speed up reactions by definite amounts
d.
Enzymes determine the direction of a reaction
The
ability of FADH to be oxidized is __________ than the ability of FAD to be
oxidized.
a.
greater
b.
lesser
c.
approximately equal
d. half
An
endergonic reaction is one that __________.
a.
requires energy in order to proceed
b.
releases energy for work
c.
gives off much heat
d.
looses energy
In
the reaction, C6H12O6 + 6O2 → 6CO2 + 6H2O + energy, which component is being
reduced?
a.
O2
b. CO2
c.
H2O
d.
Energy
The
affinity of an enzyme for its substrate, when the enzyme has a Km of 0.50 M
will be __________ than the affinity of an enzyme for its substrate when the
enzyme has a Km of 0.05 M.
a.
greater
b.
lesser
c.
approximately equal
d. half
Anthranilate
synthase, the first enzyme of tryptophan biosynthesis after the branch point
shows feedback inhibition and repression due to __________.
a.
L-tryptophan
b.
D-L-tryptophan hydantoin
c.
L-serine
d.
pyruvate
A
substrate binds to its enzyme at a location called the __________ site.
a.
coenzyme
b.
substrate
c.
active
d.
polypeptide
Hydrogen
and oxygen release enormous amounts of energy when they react. Yet, hydrogen
and oxygen can be mixed together in a balloon and nothing will happen. Why?
a.
Competitive inhibitors are blocking the reaction from occurring in the active
site
b.
There must be contaminating elements in the balloon that prohibit the reaction
from occurring
c. The
energy of activation to form the transition-state complex is too high to allow
the reaction to occur without assistance
d. all
of the above
Adenosine
triphosphate is a type of __________.
a.
fatty acid
b.
amino acid
c.
nucleotide
d.
steroid
An
enzyme that is always produced, regardless of the presence of substrates or the
end products, is called __________.
a. a
constitutive enzyme
b. an
isoenzyme
c. a
repressible enzyme
d. an
allosteric enzyme
About
7.3 kcal/mole are released when __________.
a.
glucose is converted to CO2 and H2O
b. NAD+
is reduced to NADH
c. ATP
hydrolysis is coupled to sucrose synthesis
d. the
terminal phosphate bond of ATP is broken by hydrolysis
The
ability of CTP to bind to aspartate carbamoyltransferase and shut down the
synthesis of more CTP is an example of __________.
a.
enzyme induction
b.
enzyme repression
c.
feedback inhibition of enzyme activity
d. none
of these