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CAMPBELL
BIOLOGY
TENTH
EDITION
Reece • Urry • Cain • Wasserman • Minorsky • Jackson
8
An Introduction to
Metabolism
Clicker Questions by
Scott Meissner
© 2014 Pearson Education, Inc.
How do living organisms create macromolecules,
organelles, cells, tissues, and complex higher-order
structures?
a) The laws of thermodynamics do not apply to
living organisms.
b) Living organisms create order by recycling and
reusing energy from the sun.
c) Living organisms create order locally, but the
energy transformations generate waste heat
that increases the entropy of the universe.
© 2014 Pearson Education, Inc.
How do living organisms create macromolecules,
organelles, cells, tissues, and complex higher-order
structures?
a) The laws of thermodynamics do not apply to
living organisms.
b) Living organisms create order by recycling and
reusing energy from the sun.
c) Living organisms create order locally, but the
energy transformations generate waste heat
that increases the entropy of the universe.
© 2014 Pearson Education, Inc.
Entropy can drive a chemical reaction; for example,
a) A  B  C
b) B  C  A  D
c) A  B  C  D
d) A  B  C  D  E  F
e) A  B
© 2014 Pearson Education, Inc.
Entropy can drive a chemical reaction; for example,
a) A  B  C
b) B  C  A  D
c) A  B  C  D
d) A  B  C  D  E  F
e) A  B
© 2014 Pearson Education, Inc.
Are most chemical reactions at equilibrium in living
cells?
a) yes
b) no
c) only the exergonic reactions
d) all reactions except those powered by ATP
hydrolysis
© 2014 Pearson Education, Inc.
Are most chemical reactions at equilibrium in living
cells?
a) yes
b) no
c) only the exergonic reactions
d) all reactions except those powered by ATP
hydrolysis
© 2014 Pearson Education, Inc.
A reaction has a G of 5.6 kcal/mol. Which of the
following would most likely be true?
a) The reaction could be coupled to power an
endergonic reaction with a G of 8.8 kcal/mol.
b) The reaction is nonspontaneous.
c) To take place, the reaction would need to couple
to ATP hydrolysis.
d) The reaction would result in products with a greater
free-energy content than in the initial reactants.
e) The reaction would proceed by itself but might
be very slow.
© 2014 Pearson Education, Inc.
A reaction has a G of 5.6 kcal/mol. Which of the
following would most likely be true?
a) The reaction could be coupled to power an
endergonic reaction with a G of 8.8 kcal/mol.
b) The reaction is nonspontaneous.
c) To take place, the reaction would need to couple
to ATP hydrolysis.
d) The reaction would result in products with a greater
free-energy content than in the initial reactants.
e) The reaction would proceed by itself but might
be very slow.
© 2014 Pearson Education, Inc.
True or false: The breakdown of food molecules in the
gut does not require coupling of ATP hydrolysis, but
enzymes are required to speed up these spontaneous
reactions.
a) true
b) false, because enzymes change the G to a
negative value
c) false, because enzymes are not required, as
breakdown is spontaneous and spontaneous
reactions always occur very rapidly
© 2014 Pearson Education, Inc.
True or false: The breakdown of food molecules in the
gut does not require coupling of ATP hydrolysis, but
enzymes are required to speed up these spontaneous
reactions.
a) true
b) false, because enzymes change the G to a
negative value
c) false, because enzymes are not required, as
breakdown is spontaneous and spontaneous
reactions always occur very rapidly
© 2014 Pearson Education, Inc.
The oxidation of glucose to CO2 and H2O is highly
exergonic: G  636 kcal/mole. This is spontaneous,
but why is it very slow?
a) Few glucose and oxygen molecules have the
activation energy at room temperature.
b) There is too much CO2 in the air.
c) CO2 has higher energy than glucose.
d) The formation of six CO2 molecules from one
glucose molecule decreases entropy.
e) The water molecules quench the reaction.
© 2014 Pearson Education, Inc.
The oxidation of glucose to CO2 and H2O is highly
exergonic: G  636 kcal/mole. This is spontaneous,
but why is it very slow?
a) Few glucose and oxygen molecules have the
activation energy at room temperature.
b) There is too much CO2 in the air.
c) CO2 has higher energy than glucose.
d) The formation of six CO2 molecules from one
glucose molecule decreases entropy.
e) The water molecules quench the reaction.
© 2014 Pearson Education, Inc.
Firefly luciferase catalyzes the following reaction:
luciferin  ATP  adenyl-luciferin  pyrophosphate
Then the next reaction occurs spontaneously:
adenyl-luciferin  O2  oxyluciferin  H2O  CO2  AMP  light
What is the role of luciferase?
a) Luciferase makes the G of the reaction more negative.
b) Luciferase lowers the energy of the transition state
of the reaction.
c) Luciferase alters the equilibrium point of the reaction.
d) Luciferase makes the reaction irreversible.
e) Luciferase creates a phosphorylated intermediate.
© 2014 Pearson Education, Inc.
Firefly luciferase catalyzes the following reaction:
luciferin  ATP  adenyl-luciferin  pyrophosphate
Then the next reaction occurs spontaneously:
adenyl-luciferin  O2  oxyluciferin  H2O  CO2  AMP  light
What is the role of luciferase?
a) Luciferase makes the G of the reaction more negative.
b) Luciferase lowers the energy of the transition state
of the reaction.
c) Luciferase alters the equilibrium point of the reaction.
d) Luciferase makes the reaction irreversible.
e) Luciferase creates a phosphorylated intermediate.
© 2014 Pearson Education, Inc.
In the energy diagram below, which of the energy
changes would be the same in both the enzymecatalyzed and uncatalyzed reactions?
a) a
b) b
c) c
d) d
e) e
© 2014 Pearson Education, Inc.
In the energy diagram below, which of the energy
changes would be the same in both the enzymecatalyzed and uncatalyzed reactions?
a) a
b) b
c) c
d) d
e) e
© 2014 Pearson Education, Inc.
If this is an enzyme-catalyzed reaction, how can the
rate of this reaction be increased beyond the maximum
velocity in this figure?
a) Increase the substrate
concentration.
b) Increase the amount
of enzyme.
c) Raise the temperature
to be more optimal.
d) B is the best choice, but
A and C are also possible.
e) There is no way to increase the rate
of the reaction any further.
© 2014 Pearson Education, Inc.
If this is an enzyme-catalyzed reaction, how can the
rate of this reaction be increased beyond the maximum
velocity in this figure?
a) Increase the substrate
concentration.
b) Increase the amount
of enzyme.
c) Raise the temperature
to be more optimal.
d) B is the best choice, but
A and C are also possible.
e) There is no way to increase the rate
of the reaction any further.
© 2014 Pearson Education, Inc.
Vioxx and other prescription nonsteroidal antiinflammatory drugs (NSAIDs) are potent inhibitors of
the cyclooxygenase-2 (COX-2) enzyme. High substrate
concentrations reduce the efficacy of inhibition by these
drugs. These drugs are
a) competitive inhibitors.
b) noncompetitive inhibitors.
c) allosteric regulators.
d) prosthetic groups.
e) feedback inhibitors.
© 2014 Pearson Education, Inc.
Vioxx and other prescription nonsteroidal antiinflammatory drugs (NSAIDs) are potent inhibitors of
the cyclooxygenase-2 (COX-2) enzyme. High substrate
concentrations reduce the efficacy of inhibition by these
drugs. These drugs are
a) competitive inhibitors.
b) noncompetitive inhibitors.
c) allosteric regulators.
d) prosthetic groups.
e) feedback inhibitors.
© 2014 Pearson Education, Inc.
How does the flow of energy through life differ from the
flow of matter through life?
a) Matter can be recycled, while some energy is
always converted to unusable forms like heat.
b) Matter is brought into life from outside, while
energy is generated from within life.
c) Life is able to convert energy into matter,
through photosynthesis.
d) Matter is conserved, while life causes energy
to be lost over time.
e) Life uses the flow of matter to keep its energy
state unbalanced.
© 2014 Pearson Education, Inc.
How does the flow of energy through life differ from the
flow of matter through life?
a) Matter can be recycled, while some energy is
always converted to unusable forms like heat.
b) Matter is brought into life from outside, while
energy is generated from within life.
c) Life is able to convert energy into matter,
through photosynthesis.
d) Matter is conserved, while life causes energy
to be lost over time.
e) Life uses the flow of matter to keep its energy
state unbalanced.
© 2014 Pearson Education, Inc.
The form of energy that is typically LEAST useful to life
is energy in
a) concentration gradients.
b) electrical gradients.
c) differences between distinct forms of molecules.
d) the form of heat.
e) electromagnetic radiation.
© 2014 Pearson Education, Inc.
The form of energy that is typically LEAST useful to life
is energy in
a) concentration gradients.
b) electrical gradients.
c) differences between distinct forms of molecules.
d) the form of heat.
e) electromagnetic radiation.
© 2014 Pearson Education, Inc.
Which choice best describes what the H ATPase
(see figure on next slide) does in terms of flow of
energy in many cells?
a) It converts light energy into energy in a
concentration gradient.
b) It converts matter into energy in the form of an
electrochemical gradient.
c) It pumps protons up their pressure gradient.
d) It converts chemical energy to energy in an
electrochemical gradient and heat.
e) It converts energy in a concentration gradient
to energy in an electrical gradient.
© 2014 Pearson Education, Inc.
© 2014 Pearson Education, Inc.
Which choice best describes what the H ATPase
(see figure on next slide) does in terms of flow of
energy in many cells?
a) It converts light energy into energy in a
concentration gradient.
b) It converts matter into energy in the form of an
electrochemical gradient.
c) It pumps protons up their pressure gradient.
d) It converts chemical energy to energy in an
electrochemical gradient and heat.
e) It converts energy in a concentration gradient
to energy in an electrical gradient.
© 2014 Pearson Education, Inc.
In the reaction shown on the next slide, which of the
following statements is true?
a) The greater the activation energy barrier, the slower
the reaction rate.
b) The less energy released when products form, the
slower the reaction rate.
c) The more types of reactants involved in the reaction,
the faster the reaction.
d) The higher the net G of the reaction, the faster the
reaction rate.
e) The more bonds altered by the reaction, the faster
the reaction rate.
© 2014 Pearson Education, Inc.
The reactants AB and CD must absorb
enough energy from the surroundings
to reach the unstable transition state,
where bonds can break.
© 2014 Pearson Education, Inc.
After bonds have broken,
new bonds form, releasing
energy to the surroundings.
In the reaction shown on the next slide, which of the
following is true?
a) The greater the activation energy barrier, the
slower the reaction rate.
b) The less energy released when products form, the
slower the reaction rate.
c) The more types of reactants involved in the reaction,
the faster the reaction.
d) The higher the net G of the reaction, the faster the
reaction rate.
e) The more bonds altered by the reaction, the faster
the reaction rate.
© 2014 Pearson Education, Inc.
Some enzymes can couple the hydrolysis of ATP to ion
transport by having
a) energy from ATP hydrolysis alter the free energy
changes of another reaction.
b) cofactors that act to transfer energy and matter from one
reaction to another.
c) phosphate groups from the ATP temporarily donated to
the ions.
d) the coupled processes both
be exergonic.
e) changes during ATP hydrolysis
alter the enzyme’s shape, forcing
ionic transport to occur.
© 2014 Pearson Education, Inc.
Some enzymes can couple the hydrolysis of ATP to ion
transport by having
a) energy from ATP hydrolysis alter the free energy
changes of another reaction.
b) cofactors that act to transfer energy and matter from one
reaction to another.
c) phosphate groups from the ATP temporarily donated to
the ions.
d) the coupled processes both
be exergonic.
e) changes during ATP hydrolysis
alter the enzyme’s shape, forcing
ionic transport to occur.
© 2014 Pearson Education, Inc.
The combination of ATP with water, leading to the formation
of ADP and free inorganic phosphate ion,
a) has a very large G compared to other reactions
occurring in life.
b) is an exergonic reaction due to the energy stored in the
bonds of the water molecule.
c) has neither the smallest nor the largest G seen in
reactions in life.
d) will occur rapidly even in the
absence of a specific enzyme.
e) has a very small G
compared to other reactions
occurring in life.
© 2014 Pearson Education, Inc.
The combination of ATP with water, leading to the formation
of ADP and free inorganic phosphate ion,
a) has a very large G compared to other reactions
occurring in life.
b) is an exergonic reaction due to the energy stored in the
bonds of the water molecule.
c) has neither the smallest nor the largest G seen in
reactions in life.
d) will occur rapidly even in the
absence of a specific enzyme.
e) has a very small G
compared to other reactions
occurring in life.
© 2014 Pearson Education, Inc.
In their work, Commerford et al. (2002) isolated the
glucose-6-phosphatase enzyme from rat liver tissue.
Enzyme reaction rates were assayed twice at various
concentrations of the substrate (see figure on next slide).
Which choice is LEAST likely to account for the differences
between these two sets of data?
a) The lower data set was done using a suboptimal pH
for this enzyme.
b) The upper data set was taken nearer to this
enzyme’s temperature optimum.
c) The upper curve’s assay was done using a higher
enzyme concentration.
d) The lower data set was taken while a competitive
inhibitor was present.
© 2014 Pearson Education, Inc.
© 2014 Pearson Education, Inc.
In their work, Commerford et al. (2002) isolated the
glucose-6-phosphatase enzyme from rat liver tissue.
Enzyme reaction rates were assayed twice at various
concentrations of the substrate. Which choice is LEAST
likely to account for the differences between these two sets
of data?
a) The lower data set was done using a suboptimal pH
for this enzyme.
b) The upper data set was taken nearer to this
enzyme’s temperature optimum.
c) The upper curve’s assay was done using a higher
enzyme concentration.
d) The lower data set was taken while a competitive
inhibitor was present.
© 2014 Pearson Education, Inc.
The relative free energies for progress through the reaction A +
B ÷ C + D under standard conditions (1 M concentrations and
standard temperature and pressure) are shown on the next
slide.
Changes in the conditions resulted in the altered plots shown
below. Which choice matches the proper plot in the correct
order for the reaction run with?
1) An enzyme being present.
2) At a higher temperature.
3) With lower concentrations of A + B.
4) At a colder temperature.
a) 1 A, 2 D, 3 B, 4 C
d) 1 B, 2 A, 3 D, 4 C
b) 1 B, 2 C, 3 D, 4 A
e) 1 D, 2 B, 3 C, 4 D
c)
1 C, 2 D, 3 A, 4 B
© 2014 Pearson Education, Inc.
© 2014 Pearson Education, Inc.
The relative free energies for progress through the reaction A +
B ÷ C + D under standard conditions (1 M concentrations and
standard temperature and pressure) are shown on the next
slide.
Changes in the conditions resulted in the altered plots shown
below. Which choice matches the proper plot in the correct
order for the reaction run with?
1) An enzyme being present.
2) At a higher temperature.
3) With lower concentrations of A + B.
4) At a colder temperature.
a) 1 A, 2 D, 3 B, 4 C
d) 1 B, 2 A, 3 D, 4 C
b) 1 B, 2 C, 3 D, 4 A
e) 1 D, 2 B, 3 C, 4 D
c)
1 C, 2 D, 3 A, 4 B
© 2014 Pearson Education, Inc.
How are the effects of negative feedback and allosteric
factors similar to how enzymes often couple reactions?
a) All can drive an endergonic reaction forward by
their exergonic energy changes.
b) These all often involve inducing structural
changes in the enzyme, influencing its activities.
c) Permanent changes are made to the item(s)
bound by the enzyme in each case.
d) Each leads to the formation of new covalent
bonds in the enzyme.
e) All three can lower the activation energy barrier
and speed the rate of a reaction.
© 2014 Pearson Education, Inc.
How are the effects of negative feedback and allosteric
factors similar to how enzymes often couple reactions?
a) All can drive an endergonic reaction forward by
their exergonic energy changes.
b) These all often involve inducing structural
changes in the enzyme, influencing its activities.
c) Permanent changes are made to the item(s)
bound by the enzyme in each case.
d) Each leads to the formation of new covalent
bonds in the enzyme.
e) All three can lower the activation energy barrier
and speed the rate of a reaction.
© 2014 Pearson Education, Inc.
A change in the coding region of a gene can lead to a
new allele for that gene. Which property of the protein,
coded for by this new allele, could be changed as a
result?
a) its affinity for its substrate
b) the amino acid sequence in it
c) its ability to be affected by allosteric factors
d) the pH that is optimal for its activity
e) All of the above could be altered by mutations.
© 2014 Pearson Education, Inc.
A change in the coding region of a gene can lead to a
new allele for that gene. Which property of the protein,
coded for by this new allele, could be changed as a
result?
a) its affinity for its substrate
b) the amino acid sequence in it
c) its ability to be affected by allosteric factors
d) the pH that is optimal for its activity
e) All of the above could be altered by mutations.
© 2014 Pearson Education, Inc.