Deck 3: Energy and Enzymes

Question 1

Which of the following occurs when there are more reactants than products for a reaction?

A) The reaction is pushed toward the reactants by the low concentration of products.
B) The reaction is pulled toward generating more reactants.
C) The greater concentration of reactants pushes the reaction forward, toward generating more products.
D) The reaction is pulled in the forward direction by the high concentration of products.

Answer 1

C

Question 2

Which of the following occurs when a reaction reaches equilibrium?

A) The rates of the forward and reverse reactions are equal.
B) The chemical reactions cease.
C) Entropy is no longer in the system.
D) The concentration of reactants equals the concentration of products.

Answer 2

A

Question 3

Which of the following best describes why thinking of entropy as disorder is problematic?

A) This idea can be applied scientifically in a precise way, and entropy is not governed by order.
B) This idea can be applied scientifically in a precise way, and entropy is governed by order.
C) This idea cannot be applied scientifically in a precise way, and entropy is governed by order.
D) This idea cannot be applied scientifically in a precise way, and entropy is not governed by order.

Answer 3

D

Question 4

Which statement best describes the first law of thermodynamics?

A) Matter can be created and destroyed.
B) Matter only changes forms.
C) Energy only changes forms.
D) Energy can be created and destroyed.

Question 5

Which of the following is a closed system?

A) a single-celled organism
B) a human
C) a gas-powered automobile
D) Earth

Question 6

Which of the following is NOT a form of energy?

A) heat
B) work
C) light
D) sound

Question 7

Suppose that an earthquake hits. Which of the following would be most likely to characterize your books being scattered on the floor all over your room?

A) The books now have less entropy.
B) The books now have more entropy.
C) The books have the same entropy.
D) The books have no entropy.

Question 8

Which of the following is Earth an example of?

A) a system that exchanges matter or energy with its surroundings
B) a system that does not exchange matter or energy with its surroundings
C) a system that exchanges only matter with its surroundings
D) a system that exchanges only energy with its surroundings

Question 9

When ATP is split into ADP and P_i, what happens to the energy that gets released?

A) The energy is transferred to the target molecule via the transfer of P_i.
B) The energy is directly transferred to the target molecule by an unknown mechanism.
C) The two remaining phosphates acquire the energy that was present in the linkage of three phosphates.
D) The energy dissipates in the form of heat.

Question 10

Which of the following best describes a dead cell as a system?

A) It is a closed system that exchanges energy with its surroundings.
B) It is an open system that exchanges energy with its surroundings.
C) It is an isolated system that does not exchange energy or matter with its surroundings.
D) It is a closed system that does not exchange energy or matter with its surroundings.

Question 11

Which of the following is a correct pair based on their shared characteristics?

A) Earth and a closed system
B) the universe and an open system
C) an ocean and a closed system
D) an ocean and an isolated system

Question 12

Which type of metabolic pathway involves building biomass?

A) catabolic
B) parabolic
C) irreversible
D) anabolic

Question 13

What does it mean that cells are open systems?

A) They take out energy and matter and maintain an ordered state.
B) They bring in energy and matter and maintain a disordered state.
C) They take out energy and matter and maintain an ordered state.
D) They bring in energy and matter and maintain an ordered state.

Question 14

Which of the following best explains why machines can never be 100% efficient?

A) the tendency of energy not to spread out
B) the tendency of energy to spread out
C) the tendency of energy to be kept
D) the tendency of energy to be lost

Question 15

Which of the following can be said to occur during every energy transformation?

A) A change occurs in the free energy of the universe.
B) The entropy of the universe increases.
C) A change occurs in the total energy of the universe.
D) The entropy of the universe decreases.

Question 16

Which of the following is a correct pair based on their shared characteristics?

A) the universe and a closed system
B) the universe and an open system
C) an ocean and an open system
D) an ocean and a closed system

Question 17

Which of the following best describes why bricks from a truck fall all over during a traffic accident?

A) The bricks have reached an equilibrium state.
B) The bricks have reached a minimum entropy state.
C) The bricks have reached a maximum free energy state.
D) The bricks have reached a minimum free energy state.

Question 18

Which of the following best illustrates the first law of thermodynamics by Niagara Falls?

A) Water at the top of the falls has high kinetic energy; as the water moves over the waterfall, its kinetic energy is converted into potential energy; when the water reaches the bottom of the waterfall, its potential energy is transformed into other types of energy: heat, sound, and mechanical energy.
B) Water at the top of the falls has high potential energy; as the water moves over the waterfall, its potential energy is converted into kinetic energy; when the water reaches the bottom of the waterfall, its kinetic energy is transformed into other types of energy: heat, sound, and mechanical energy.
C) Water at the top of the falls has high potential energy; as the water moves over the waterfall, its potential energy is converted into kinetic energy; when the water reaches the bottom of the waterfall, its kinetic energy is transformed into potential energy again.
D) Water at the top of the falls has high potential energy; as the water moves over the waterfall, its potential energy is converted into kinetic energy; when the water reaches the bottom of the waterfall, its kinetic energy is lost.

Question 19

Which of the following is an exergonic reaction?

A) folding laundry
B) synthesizing a protein
C) burning wood for a campfire
D) building a tower out of blocks

Question 20

Which of the following best describes an ocean as an open system?

A) It does not exchange matter with its surroundings.
B) It absorbs but not releases energy.
C) It absorbs and releases energy.
D) It exchanges energy but not matter with its surroundings.

Question 21

Figure 3-5
Refer to the graph in Figure 3-5. Which phrase best describes what the graph represents?

A) enzyme activity as a function of pH in a fairly neutral environment
B) enzyme activity as a function of pH in a strongly acidic environment
C) enzyme activity as a function of temperature
D) enzyme activity as a function of pH in a strongly basic environment

Question 22

Figure 3-5
According to the graph in Figure 3-5, what is the optimal pH for enzyme 1?

A) 2
B) 3
C) 4
D) 5

Question 23

Figure 3-1
What does it mean when an enzyme is saturated?

A) It means the enzymes need more reactants.
B) It means the enzymes have sufficient reactants available for optimal activity.
C) It means the enzymes cannot continue to catalyze the reaction.
D) It means the reaction is at equilibrium.

Question 24

All enzymes are proteins.

Question 25

Reactions that reach an equilibrium point are reversible.

Question 26

Figure 3-5
Suppose all three enzymes represented in Figure 3-5 catalyze the same reaction, but conditions require you to use a pH of 7. Which is the best enzyme to use?

A) enzyme 3
B) enzyme 2
C) either enzyme 1 or 2
D) enzyme 1

Question 27

Enzymes alter the equilibrium point of a reaction.

Question 28

Figure 3-3
Refer to Figure 3-3. What does it mean when an enzyme has an allosteric activator?

A) The product of the enzyme, or another downstream product, will bind to the enzyme at a site other than the active site and inhibit enzyme activity.
B) The product of the enzyme, or another downstream product, will bind to the enzyme at the active site and stimulate enzyme activity.
C) The product of the enzyme, or another downstream product, will bind to the enzyme at a site other than the active site and stimulate enzyme activity.
D) The product of the enzyme, or another downstream product, will bind to the enzyme at the active site and inhibit enzyme activity.

Question 29

Figure 3-1
Refer to Figure 3-1. Suppose you conduct an experiment in the laboratory in which you add increasing amounts of substrate to a solution containing an enzyme and a pH buffer. You incubate the container at the optimal temperature for the enzyme. Each time you add more substrate, you measure the rate of the reaction. Also suppose that you graph the results such that the x-axis shows the substrate concentration and the y-axis shows the resulting reaction rate. What will you find over time?

A) The rate of the reaction will increase rapidly, taper off, and plateau.
B) The resulting graph will be a perfect bell curve.
C) The rate of the reaction will increase slowly, plateau, and then drop sharply back to zero.
D) The rate of the reaction will proceed with a slope of 1 and continue in a linear fashion indefinitely or until you run out of reactants.

Question 30

At equilibrium, the concentration of the reactants equals the concentration of the products.

Question 31

AMP is the primary energy and phosphate source in coupled reactions.

Question 32

Which sentence best describes the situation that occurs when an enzyme and its substrate interact?

A) Just after substrate binding, the enzyme changes its shape (conformation) so that the active site becomes even more precise in its ability to bind the substrate.
B) Just before substrate binding, the substrate changes its shape (conformation) so that the active site becomes even more precise in its ability to bind the enzyme.
C) Just before substrate binding, the enzyme changes its shape (conformation) so that the active site becomes even more precise in its ability to bind the substrate.
D) Just after substrate binding, the substrate changes its shape (conformation) so that the active site becomes even more precise in its ability to bind the enzyme.

Question 33

Figure 3-3
Refer to Figure 3-3. Which sentence best describes the process of noncompetitive feedback inhibition?

A) The inhibitor binds to the active site and directly blocks the active site of the enzyme.
B) The products of the reaction at the end of the pathway bind to a site other than the active site of an enzyme at or near the beginning of the pathway, and block enzyme activity indirectly.
C) The products of the reaction at the end of the pathway block the active site of the enzyme, inhibiting it directly.
D) The substrate and cofactors compete for the active site of an enzyme and block enzyme activity directly.

Question 34

Activation energy is not required for nonspontaneous reactions.

Question 35

What is the difference between cofactors and coenzymes?

A) Cofactors tend to be complex molecules, but coenzymes are generally ions.
B) Cofactors are not necessary, but coenzymes are necessary.
C) Cofactors can be inorganic or organic, but coenzymes are always inorganic.
D) Cofactors can be inorganic or organic, but coenzymes are just another name for organic cofactors.

Question 36

Figure 3-2
Which sentence best describes the process of competitive inhibition? Refer to Figure 3-2.

A) The inhibitor binds and directly blocks the active site of the enzyme.
B) The products of the reaction block the active site of the enzyme.
C) The substrate and cofactors compete for the active site.
D) The inhibitor binds to a site other than the active site of the enzyme and blocks enzyme activity indirectly.

Question 37

Suppose you decide to alter the rate of a reaction. Which of the following would you do to reverse the enzyme-catalyzed reaction?

A) add more reactants
B) add more enzyme
C) mechanically stir the contents of a beaker of reactants
D) add more product

Question 38

Which of the following describes the main mechanism of enzymes?

A) removing reactants from a solution in a set ratio that enhances the chances of the remaining individual reactants interacting with each other
B) forcing the reactants into an altered environment, which in turn creates a change in the free energy of the reactants relative to the products
C) increasing the probability that the reactants will come into close proximity to each other in the proper orientation for forming the transition state molecule
D) altering the equilibrium point of a particular reaction to favour the formation of products

Question 39

Enzymes work with at least three mechanisms. Which of the following is NOT a mechanism by which enzymes function?

A) by putting reactants in close proximity to each other
B) by altering the free energy (G) of the reaction
C) by orienting the reactants so they are positioned to favour the transition state
D) by altering the immediate environment of the reactants to promote reactant interactions

Question 40

Figure 3-5
According to the graph in Figure 3-5, what is the optimal pH for enzyme 2?

A) 6
B) 7
C) 8
D) 9

Question 41

Match each definition with the corresponding term.
a.primary coupling agent in cellular reactions
b.addition of a phosphate group to a target molecule
c.product of the reaction interacts with an enzyme in a noncompetitive way to inhibit or enhance enzyme activity
d.linking of an exergonic reaction with an endergonic reaction that allows a cell to drive a nonspontaneous reaction to completion
e.series of chemical reactions where the products of one reaction are the reactants for a subsequent reaction
f.substance that facilitates a chemical reaction without itself being consumed by the reaction
g.energy needed to start a reaction, be it endergonic or exergonic
h.portion of the enzyme that binds to a reactant or reactants
i.state in which the rate of the forward reaction equals the rate of the reverse reaction
j.intermediate arrangement of unstable bonds between atoms that can proceed toward either the reactants or the products of a reaction
k.
reactant molecule that binds to an enzyme
phosphorylation

Question 42

Enzyme activity is increased by falling temperatures.

Question 43

Match each definition with the corresponding term.
a.primary coupling agent in cellular reactions
b.addition of a phosphate group to a target molecule
c.product of the reaction interacts with an enzyme in a noncompetitive way to inhibit or enhance enzyme activity
d.linking of an exergonic reaction with an endergonic reaction that allows a cell to drive a nonspontaneous reaction to completion
e.series of chemical reactions where the products of one reaction are the reactants for a subsequent reaction
f.substance that facilitates a chemical reaction without itself being consumed by the reaction
g.energy needed to start a reaction, be it endergonic or exergonic
h.portion of the enzyme that binds to a reactant or reactants
i.state in which the rate of the forward reaction equals the rate of the reverse reaction
j.intermediate arrangement of unstable bonds between atoms that can proceed toward either the reactants or the products of a reaction
k.
reactant molecule that binds to an enzyme
ATP

Question 44

Explain how a cell can use catabolic reactions to drive anabolic reactions, despite energy loss in the form of entropy and heat.

Question 45

Match each definition with the corresponding term.
a.primary coupling agent in cellular reactions
b.addition of a phosphate group to a target molecule
c.product of the reaction interacts with an enzyme in a noncompetitive way to inhibit or enhance enzyme activity
d.linking of an exergonic reaction with an endergonic reaction that allows a cell to drive a nonspontaneous reaction to completion
e.series of chemical reactions where the products of one reaction are the reactants for a subsequent reaction
f.substance that facilitates a chemical reaction without itself being consumed by the reaction
g.energy needed to start a reaction, be it endergonic or exergonic
h.portion of the enzyme that binds to a reactant or reactants
i.state in which the rate of the forward reaction equals the rate of the reverse reaction
j.intermediate arrangement of unstable bonds between atoms that can proceed toward either the reactants or the products of a reaction
k.
reactant molecule that binds to an enzyme
equilibrium point

Question 46

For each situation, choose the most appropriate term.
a.endergonic
b.exergonic
c.equilibrium
a beaker of water sitting on a bench

Question 47

Match each definition with the corresponding term.
a.primary coupling agent in cellular reactions
b.addition of a phosphate group to a target molecule
c.product of the reaction interacts with an enzyme in a noncompetitive way to inhibit or enhance enzyme activity
d.linking of an exergonic reaction with an endergonic reaction that allows a cell to drive a nonspontaneous reaction to completion
e.series of chemical reactions where the products of one reaction are the reactants for a subsequent reaction
f.substance that facilitates a chemical reaction without itself being consumed by the reaction
g.energy needed to start a reaction, be it endergonic or exergonic
h.portion of the enzyme that binds to a reactant or reactants
i.state in which the rate of the forward reaction equals the rate of the reverse reaction
j.intermediate arrangement of unstable bonds between atoms that can proceed toward either the reactants or the products of a reaction
k.
reactant molecule that binds to an enzyme
metabolic pathway

Question 48

Enzymes do not change the ΔG of a reaction.

Question 49

For each situation, choose the most appropriate term.
a.endergonic
b.exergonic
c.equilibrium
a reaction where ΔG is negative

Question 50

Match each definition with the corresponding term.
a.primary coupling agent in cellular reactions
b.addition of a phosphate group to a target molecule
c.product of the reaction interacts with an enzyme in a noncompetitive way to inhibit or enhance enzyme activity
d.linking of an exergonic reaction with an endergonic reaction that allows a cell to drive a nonspontaneous reaction to completion
e.series of chemical reactions where the products of one reaction are the reactants for a subsequent reaction
f.substance that facilitates a chemical reaction without itself being consumed by the reaction
g.energy needed to start a reaction, be it endergonic or exergonic
h.portion of the enzyme that binds to a reactant or reactants
i.state in which the rate of the forward reaction equals the rate of the reverse reaction
j.intermediate arrangement of unstable bonds between atoms that can proceed toward either the reactants or the products of a reaction
k.
reactant molecule that binds to an enzyme
transition state

Question 51

Match each definition with the corresponding term.
a.primary coupling agent in cellular reactions
b.addition of a phosphate group to a target molecule
c.product of the reaction interacts with an enzyme in a noncompetitive way to inhibit or enhance enzyme activity
d.linking of an exergonic reaction with an endergonic reaction that allows a cell to drive a nonspontaneous reaction to completion
e.series of chemical reactions where the products of one reaction are the reactants for a subsequent reaction
f.substance that facilitates a chemical reaction without itself being consumed by the reaction
g.energy needed to start a reaction, be it endergonic or exergonic
h.portion of the enzyme that binds to a reactant or reactants
i.state in which the rate of the forward reaction equals the rate of the reverse reaction
j.intermediate arrangement of unstable bonds between atoms that can proceed toward either the reactants or the products of a reaction
k.
reactant molecule that binds to an enzyme
catalyst

Question 52

Explain how temperature can affect enzyme activity.

Question 53

Match each definition with the corresponding term.
a.primary coupling agent in cellular reactions
b.addition of a phosphate group to a target molecule
c.product of the reaction interacts with an enzyme in a noncompetitive way to inhibit or enhance enzyme activity
d.linking of an exergonic reaction with an endergonic reaction that allows a cell to drive a nonspontaneous reaction to completion
e.series of chemical reactions where the products of one reaction are the reactants for a subsequent reaction
f.substance that facilitates a chemical reaction without itself being consumed by the reaction
g.energy needed to start a reaction, be it endergonic or exergonic
h.portion of the enzyme that binds to a reactant or reactants
i.state in which the rate of the forward reaction equals the rate of the reverse reaction
j.intermediate arrangement of unstable bonds between atoms that can proceed toward either the reactants or the products of a reaction
k.
reactant molecule that binds to an enzyme
active site

Question 54

Match each definition with the corresponding term.
a.primary coupling agent in cellular reactions
b.addition of a phosphate group to a target molecule
c.product of the reaction interacts with an enzyme in a noncompetitive way to inhibit or enhance enzyme activity
d.linking of an exergonic reaction with an endergonic reaction that allows a cell to drive a nonspontaneous reaction to completion
e.series of chemical reactions where the products of one reaction are the reactants for a subsequent reaction
f.substance that facilitates a chemical reaction without itself being consumed by the reaction
g.energy needed to start a reaction, be it endergonic or exergonic
h.portion of the enzyme that binds to a reactant or reactants
i.state in which the rate of the forward reaction equals the rate of the reverse reaction
j.intermediate arrangement of unstable bonds between atoms that can proceed toward either the reactants or the products of a reaction
k.
reactant molecule that binds to an enzyme
coupled reaction

Question 55

Match each definition with the corresponding term.
a.primary coupling agent in cellular reactions
b.addition of a phosphate group to a target molecule
c.product of the reaction interacts with an enzyme in a noncompetitive way to inhibit or enhance enzyme activity
d.linking of an exergonic reaction with an endergonic reaction that allows a cell to drive a nonspontaneous reaction to completion
e.series of chemical reactions where the products of one reaction are the reactants for a subsequent reaction
f.substance that facilitates a chemical reaction without itself being consumed by the reaction
g.energy needed to start a reaction, be it endergonic or exergonic
h.portion of the enzyme that binds to a reactant or reactants
i.state in which the rate of the forward reaction equals the rate of the reverse reaction
j.intermediate arrangement of unstable bonds between atoms that can proceed toward either the reactants or the products of a reaction
k.
reactant molecule that binds to an enzyme
allosteric regulation

Question 56

For each situation, choose the most appropriate term.
a.endergonic
b.exergonic
c.equilibrium
a reaction where ΔG = 0

Question 57

Explain three ways in which other molecules regulate enzymes.

Question 58

Match each definition with the corresponding term.
a.primary coupling agent in cellular reactions
b.addition of a phosphate group to a target molecule
c.product of the reaction interacts with an enzyme in a noncompetitive way to inhibit or enhance enzyme activity
d.linking of an exergonic reaction with an endergonic reaction that allows a cell to drive a nonspontaneous reaction to completion
e.series of chemical reactions where the products of one reaction are the reactants for a subsequent reaction
f.substance that facilitates a chemical reaction without itself being consumed by the reaction
g.energy needed to start a reaction, be it endergonic or exergonic
h.portion of the enzyme that binds to a reactant or reactants
i.state in which the rate of the forward reaction equals the rate of the reverse reaction
j.intermediate arrangement of unstable bonds between atoms that can proceed toward either the reactants or the products of a reaction
k.
reactant molecule that binds to an enzyme
substrate

Question 59

For each situation, choose the most appropriate term.
a.endergonic
b.exergonic
c.equilibrium
a dead cell

Question 60

Match each definition with the corresponding term.
a.primary coupling agent in cellular reactions
b.addition of a phosphate group to a target molecule
c.product of the reaction interacts with an enzyme in a noncompetitive way to inhibit or enhance enzyme activity
d.linking of an exergonic reaction with an endergonic reaction that allows a cell to drive a nonspontaneous reaction to completion
e.series of chemical reactions where the products of one reaction are the reactants for a subsequent reaction
f.substance that facilitates a chemical reaction without itself being consumed by the reaction
g.energy needed to start a reaction, be it endergonic or exergonic
h.portion of the enzyme that binds to a reactant or reactants
i.state in which the rate of the forward reaction equals the rate of the reverse reaction
j.intermediate arrangement of unstable bonds between atoms that can proceed toward either the reactants or the products of a reaction
k.
reactant molecule that binds to an enzyme
activation energy

Question 61

For each situation, choose the most appropriate term.
a.endergonic
b.exergonic
c.equilibrium
a toddler dumping boxes of toys

Question 62

For each situation, choose the most appropriate term.
a.endergonic
b.exergonic
c.equilibrium
folding laundry

Question 63

For each situation, choose the most appropriate term.
a.endergonic
b.exergonic
c.equilibrium
a reaction where ΔG is positive

Question 64

For each situation, choose the most appropriate term.
a.endergonic
b.exergonic
c.equilibrium
digestion of a candy bar

Question 65

For each situation, choose the most appropriate term.
a.endergonic
b.exergonic
c.equilibrium
the rate of synthesis equals the rate of degradation

Question 66

For each situation, choose the most appropriate term.
a.endergonic
b.exergonic
c.equilibrium
protein synthesis