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AP Bio Ch. 8 Study Guide Test Your Knowledge

Multiple Choice
Identify the choice that best completes the statement or answers the question.
 

 1. 
Catabolic and anabolic pathways are often coupled in a cell because
a.
the intermediates of a catabolic pathway are used in the anabolic pathway
b.
both pathways use the same enzyme
c.
the free energy released by one pathway is used to drive the other pathway
d.
the activation of the the catabolic pathway can be used in the anabolic pathway
e.
their enzymes are controlled by the same activators and inhibitors
 

 2. 
According to the first law of thermodynamics,
a.
for every action there is an equal and opposite reaction
b.
every energy transfer results in an increase in disorder or entropy
c.
the total amount of energy in the universe is conserved or constant
d.
energy can be transferred or transformed, but disorder always increases
e.
potential energy is converted to kinetic energy, and kinetic energy is converted to heat
 

 3. 
When a cell breaks down glucose, only about 34% of the energy is captured in ATP molecules. The remaining 66% of the energy is
a.
used to increase the order necessary for life to exist
b.
lost as heat, in accordance with the second law of thermodynamics
c.
used to increase the entropy of the system by converting kinetic energy to into potential energy
d.
stored in starch or glycogen for later use by the cell
e.
released when the the ATP molecules are hydrolyzed
 

 4. 
When glucose and O2 are converted to CO2 and H2O, changes in total energy, entropy, and free energy are correctly represented as
a.
- delta H, - delta S, - delta G
b.
- delta H, + delta S, - delta G
c.
- delta H, + delta S, + delta G
d.
+ delta H, + delta S, + delta G
e.
+ delta H, - delta S, + delta G
 

 5. 
When amino acids join to form a protein, which of the following energy and entropy changes apply?
a.
- delta H, + delta S, + delta G
b.
- delta H, - delta S, + delta G
c.
+ delta H. + delta S, + delta G
d.
+ delta H, - delta S, + delta G
e.
+ delta H. + delta S, - delta G
 

 6. 
A negative delta G means that
a.
the quantity G of energy is available to do work
b.
the reaction is spontaneous
c.
the reactants have more free energy than the products
d.
the reaction is exergonic
e.
all of the above are true
 

 7. 
One way in which a cell maintains metabolic disequalibrium is to
a.
siphon products of a reaction off to the next step in a metabolic pathway
b.
provide a constant supply of enzymes for critical reactions
c.
use feedback inhibition to turn off pathways
d.
use allosteric enzymes that can bind to activators or inhibitors
e.
use the energy from the anabolic pathways to drive catabolic pathways
 

 8. 
At equalibrium,
a.
no enzymes are functioning
b.
free energy is decreasing
c.
the forward and backwards reactions have stopped
d.
the products and reactants have equal values of H
e.
delta G is 0
 

 9. 
An endergonic reaction could be described as one that
a.
proceeds spontaneously with the addition of activation energy
b.
produces products with more free energy than the reactants
c.
is not able to be catalyzed by enzymes
d.
releases energy
e.
produces ATP for energy coupling
 

 10. 
The formation of ATP from ADP and inorganic phosphate
a.
is an exergonic process
b.
transfers the phosphate to an intermediate that becomes more reactive
c.
produces an unstable energy compound that can drive cellular work
d.
has a delta G of -7.3 kcal / mol under standard conditions
e.
involves the hydrolysis of a phosphate bond
 

 11. 
What is meant by an induced fit?
a.
The binding of the substrate as an energy-requiring process.
b.
A competitive inhibitor can outcompete the substrate for the active site.
c.
The binding of the substrate changes the shape of the active site, which can stress or bend substrate bonds.
d.
The active site creates a microenvironment ideal for the reaction.
e.
The binding of an activator to an allosteric site induces a more active form of the subunits of an enzyme.
 

 12. 
In an experiment, changing the the pH from 7 to 6 resulted in an increase in product formation. From this we could conclude that
a.
the enzyme became saturated at pH 6
b.
the enzyme’s optimal pH is 6
c.
this enzyme works best at a neutral pH
d.
the temperature must have increased when the pH was changed to 6
e.
the enzyme was was in a more active shape at pH 6
 

 13. 
When substance A was added to an enzyme reaction, product formation decreased. The addition of more substrate did not increase product formation. From this we can conclude that substance A could be
a.
product molecules
b.
a cofactor
c.
an allosteric enzyme
d.
a competitive inhibitor
e.
a noncompetitive inhibitor
 

 14. 
Which of the following characteristics is most directly responsible for the specificity of a protein enzyme?
a.
its primary structure
b.
its secondary and tertiary structures
c.
the shape and characteristics of its allosteric site
d.
its cofactors
e.
the R groups of the amino acids in its active site
 

 15. 
An enzyme raises which of the following parameters?
a.
delta G
b.
delta H
c.
the free energy of activation
d.
the speed of a reaction
e.
the equalibrium of a reaction
 

 16. 
Zinc, an essential trace element, may be found bound to the active site of some enzymes. Such zinc ions most likely function as
a.
a coenzyme derived from a vitamin
b.
a cofactor necessary for catalysis
c.
a substrate of the enzyme
d.
a competitive inhibitor of the enzyme
e.
an allosteric activator of the enzyme
 

 17. 
Which line in the diagram indicates the delta G of the enzyme-catalyzed reaction L --> M + N?
a.
a
b.
b
c.
c
d.
d
e.
e
 

 18. 
Which line in the diagram indicates the activation energy of the noncatalyzed reaction?
a.
a
b.
b
c.
c
d.
d
e.
e
 

 19. 
Which of the following terms best describes this reaction?
a.
nonspontaneous
b.
- delta G
c.
endergonic
d.
coupled reaction
e.
anabolic reaction
 

 20. 
In cooperativity,
a.
a cellular organelle contains all the enzymes needed for a metabolic pathway
b.
a product of a pathway serves as a competitive inhibitor of an enzyme early in the pathway
c.
a molecule bound to the active site of one subunit of an enzyme affects the active site of other subunits
d.
the allosteric site is filled with an activator molecule
e.
the product of one reaction serves as the substrate for the next reaction in intricately ordered metabolic pathways
 

 21. 
In the metabolic pathway A --> B --> C --> D --> E, what effect would molecule E likely have on the enzyme that catalyzes A --> B?
a.
allosteric inhibitor
b.
allosteric activator
c.
competitive inhibitor
d.
feedback activator
e.
coenzyme
 

Matching
 
 
Fill in the Blanks
a.
competitive inhibitors
f.
feedback inhibition
b.
heat
g.
metabolism
c.
phosphorylated intermediate
h.
entropy
d.
anabolic
i.
activation energy
e.
coenzymes
j.
potential
 

 22. 

 the totality of an organism’s chemical processes
 

 23. 

 pathways that use energy to synthesize complex molecules
 

 24. 

 the energy resulting from location or structure
 

 25. 

 the most random form of energy
 

 26. 

 term for the measure of disorder or randomness
 

 27. 

 the energy that must be absorbed by molecules to reach the transition state
 

 28. 

 inhibitors that decrease an enzyme’s activity by binding to the active site
 

 29. 

 organic molecules that bind to enzymes and are necessary for their functioning
 

 30. 

 regulatory device in which the product of a pathway binds to an enzyme early in the pathway
 

 31. 

 more reactive molecules created by the transfer of a phosphate group from ATP
 



 
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