40. ______ When Enzyme B carries out its reaction with a substrate concentration of 5.0
mM, the reaction velocity gradually decreases 5 minutes after the reaction starts.
What could cause this change in reaction rate?
a) Enzyme B catalyzes an irreversible reaction.
b) Enzyme B becomes saturated with substrate.
c) Enzyme B is inhibited by its product.
d) Enzyme B is working at its V
max
value.
41. ______ Which will occur when Enzyme A and Enzyme B both carry out their reaction at
pH = 7.0?
a) Enzyme A will produce more glucose than Enzyme B when [S] = 5.0 mM.
b) Enzyme B will produce more glucose than Enzyme A when [S] = 5.0 mM.
c) V
o
for Enzyme A will double as [S] increases from 5.0 mM to 10.0 mM.
d) V
o
for Enzyme B will double as [S] increases from 5.0 mM to 10.0 mM.
42. ______ Which kinetic property will be shared by Enzyme A and Enzyme B?
a) Their K
M
values will decrease as the substrate concentration decreases.
b) Their V
max
values will increase as the substrate concentration increases.
c) Their K
M
values will depend upon the concentration of the enzymes.
d) Their V
max
values will depend upon the slowest step of their reaction
mechanisms.
43. ______ The substrate for Enzyme A is a sugar phosphate while the substrate for Enzyme B
is a sugar alcohol. Which amino acid is likely to be found in the active site of both
enzymes?
a) leucine
b) tryptophan
c) aspartate
d) glutamine
44. ______ Enzyme A is an allosteric enzyme inhibited by galactose while Enzyme B is a
covalently modified enzyme inhibited by phosphate. Which will occur during their
regulation?
a)
Enzyme B will become more inhibited as the concentration of phosphate
increases.
b)
Enzyme A will become more inhibited as the concentration of galactose
increases.
c)
Both enzymes will undergo an irreversible conformational change as their
regulating molecule binds.
d)
Both enzymes will bind their regulating molecule to a specific active site
on a catalytic subunit.
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