Question 1

If you wanted to permanently block the function of an enzyme, you could add

Accepted Answer

A)  a molecule that can covalently bind to the active site. 
B)  more product. 
C)  a noncompetitive inhibitor. 
D)  an allosteric inhibitor. 
E)  a competitive inhibitor.

Question 2

What is a transition state in a chemical reaction?

Accepted Answer

A)  The place where a substrate molecule binds to an enzyme 
B)  A reactant with potential energy that is higher than that of the product 
C)  The combination of a substrate and an enzyme 
D)  The state at which the bonds of reactants are unstable 
E)  The active site where reactants are oriented

Question 3

Which parameter is indicative of how far and in what direction a reaction will progress?

Accepted Answer

A)  The concentration of reactants 
B)  The change in free energy of the reaction (F1F1F1S1F1F1F10G) 
C)  The concentration of products 
D)  The change in enthalpy of the reaction (F1F1F1S1F1F1F10H) 
E)  The overall size of the system in which the reaction occurs

Question 4

Which is an example of saturation of an enzyme-catalyzed reaction?

Accepted Answer

A)  The number of substrate molecules is much smaller than the number of available enzyme molecules. 
B)  The number of product molecules is much larger than the number of substrate molecules. 
C)  The number of substrate molecules is much larger than the number of product molecules. 
D)  The number of substrate molecules is much larger than the number of available enzyme molecules. 
E)  The number of available enzyme molecules is in equilibrium with the number of substrate molecules.

Question 5

Most enzymes are which type of macromolecule?

Accepted Answer

A)  Protein 
B)  Carbohydrate 
C)  Lipid 
D)  Nucleic acid 
E)  Hydrocarbon

Question 6

How much energy is released when 1.0 mole of ATP is hydrolyzed?

Accepted Answer

A)  0.73 kcal 
B)  730 kcal 
C)  7.3 kcal 
D)  21.7 kcal 
E)  30 kcal

Question 7

The energy released by the hydrolysis of ATP to ADP and Pi is

Accepted Answer

A)  difficult for biological systems to capture. 
B)  usually lost as heat. 
C)  less than the energy needed by the reverse reaction of ADP + Pi F1F1F1S1F1F1F10 ATP. 
D)  more than the energy needed by the reverse reaction of ADP + Pi F1F1F1S1F1F1F10 ATP. 
E)  equal to the energy needed by the reverse reaction of ADP + Pi F1F1F1S1F1F1F10 ATP.

Question 8

If the F1F1F1S1F1F1F10G of a spontaneous reaction is negative, indicating that the reaction releases free energy, the reaction is _______.

Accepted Answer

The answer of If the F1F1F1S1F1F1F10G of a spontaneous reaction...

Question 9

Each day, an adult human uses approximately 2,000 kilocalories of metabolic energy.This quantity of energy can be supplied by about 250 moles of ATP as it hydrolyzes to ADP and P_i.At any one time, there is much less than this quantity of ATP present in the human body.Therefore, the production of ATP must be tightly regulated so that appropriate amounts are available, depending on need.For example, certain enzymes involved in ATP production will be _______ when a person shifts from high levels of activity to a period of sleep.

Accepted Answer

The answer of Each day, an adult human uses approximately...

Question 10

Refer to the figure below.  Enzymes use a variety of strategies for inducing substrates to assume their transition states.Of the three strategies shown in the figure, labeled A, B, and C, the two that operate using physical mechanisms are _______.

Accepted Answer

The answer of Refer to the figure below.  Enzymes...

Question 11

The binding of an effector molecule at a regulatory site of an enzyme causes an alteration of the geometry of the active site and loss of enzymatic activity.This effector binding is freely reversible.This is an example of

Accepted Answer

A)  passive enzymatic regulation. 
B)  competitive inhibition. 
C)  noncompetitive inhibition. 
D)  irreversible inhibition. 
E)  covalent modification.

Question 12

Refer to the graph below.  The graph shows energy changes associated with a reaction that goes forward without an enzyme present.Which statement correctly describes what happens when an enzyme is added to catalyze the reaction?

Accepted Answer

A)  A changes and C does not change. 
B)  B changes and C does not change. 
C)  C changes and A does not change. 
D)  A changes and B does not change. 
E)  B changes and A does not change.

Question 13

Which is the correct general equation for an enzyme-catalyzed reaction? Enzyme is represented by "E," substrate by "S," and product by "P."

Accepted Answer

A)  E F1F1F1S1F1F1F10 S + P 
B)  P + S F1F1F1S1F1F1F10 E + P F1F1F1S1F1F1F10 EP 
C)  S F1F1F1S1F1F1F10 E + P 
D)  E + S F1F1F1S1F1F1F10 ES F1F1F1S1F1F1F10 E + P 
E)  P F1F1F1S1F1F1F10 E + P F1F1F1S1F1F1F10 EP F1F1F1S1F1F1F10 S

Question 14

The enzyme glyceraldehyde 3-phosphate dehydrogenase catalyzes the reaction glyceraldehyde 3-phosphate F1F1F1S1F1F1F10 1,3-diphosphoglycerate.The binding of the glyceraldehyde 3-phosphate to the enzyme creates a(n)

Accepted Answer

A)  transition state. 
B)  activation groove. 
C)  catalyst. 
D)  enzyme-substrate complex. 
E)  energy barrier.

Question 15

Refer to the diagram below showing the activity of several enzymes at varying pH levels.  Based on the diagram, what is the pH at which pepsin would exhibit the most activity?

Accepted Answer

A)  1.0 
B)  1.5 
C)  2.0 
D)  2.8 
E)  3.4

Question 16

In an experiment, a small amount of allosteric inhibitor is added to tube A and no inhibitor is added to tube B.The full reaction is completed in tube B twice as quickly as it is completed in tube A.The allosteric inhibitor acted by

Accepted Answer

A)  decreasing the number of enzyme molecules. 
B)  increasing the amount of the active form of the enzyme. 
C)  decreasing the amount of the inactive form of the enzyme. 
D)  decreasing the amount of the active form of the enzyme. 
E)  increasing the amount of substrate.

Question 17

Which action would reverse the effects of a competitive inhibitor on an enzyme but not the effects of a noncompetitive or an irreversible inhibitor?

Accepted Answer

A)  Dilute the solution by adding more solvent. 
B)  Add an allosteric activator. 
C)  Heat the solution. 
D)  Add substrate. 
E)  Remove substrate.

Question 18

Living things use chemical reactions to live, grow, and reproduce.Chemical reactions are accompanied by energy changes.Which term refers to the topic of energy change in chemical reactions?

Accepted Answer

A)  Thermodynamics 
B)  Catalysis 
C)  Entropy 
D)  Enthalpy 
E)  Equilibrium

Question 19

A reaction with a F1F1F1S1F1F1F10G of ‒14.3 kcal/mol releases energy that is then used by a second reaction with a F1F1F1S1F1F1F10G of +10.2 kcal/mol.The net free energy change of the coupled reactions is _______.

Accepted Answer

The answer of A reaction with a F1F1F1S1F1F1F10G of ‒14.3...

Question 20

Certain types of cells have very low levels of metabolic activity for long time periods, but then rapidly shift to grow and divide.To undergo this shift, these cells must activate anabolic pathways.Which is one way they are able to accomplish this?

Accepted Answer

A)  Large molecules influence metabolic flux through competitive inhibition effects on enzymes. 
B)  Small molecules affect metabolic flux through allosteric effects on enzymes. 
C)  Anabolic enzymes inhibit catabolic enzymes. 
D)  Cells begin directing all of their energy toward reactions with negative F1F1F1S1F1F1F10Gs. 
E)  Cells only synthesize anabolic enzymes and cease synthesizing catabolic enzymes.

Exam 8: Energy, Enzymes, and Metabolism

If you wanted to permanently block the function of an enzyme, you could add

What is a transition state in a chemical reaction?

Which parameter is indicative of how far and in what direction a reaction will progress?

Which is an example of saturation of an enzyme-catalyzed reaction?

Most enzymes are which type of macromolecule?

How much energy is released when 1.0 mole of ATP is hydrolyzed?

The energy released by the hydrolysis of ATP to ADP and P_i is

If the G of a spontaneous reaction is negative, indicating that the reaction releases free energy, the reaction is _______.

Refer to the figure below. Enzymes use a variety of strategies for inducing substrates to assume their transition states.Of the three strategies shown in the figure, labeled A, B, and C, the two that operate using physical mechanisms are _______.

The binding of an effector molecule at a regulatory site of an enzyme causes an alteration of the geometry of the active site and loss of enzymatic activity.This effector binding is freely reversible.This is an example of

Refer to the graph below. The graph shows energy changes associated with a reaction that goes forward without an enzyme present.Which statement correctly describes what happens when an enzyme is added to catalyze the reaction?

Which is the correct general equation for an enzyme-catalyzed reaction? Enzyme is represented by "E," substrate by "S," and product by "P."

The enzyme glyceraldehyde 3-phosphate dehydrogenase catalyzes the reaction glyceraldehyde 3-phosphate  1,3-diphosphoglycerate.The binding of the glyceraldehyde 3-phosphate to the enzyme creates a(n)

Refer to the diagram below showing the activity of several enzymes at varying pH levels. Based on the diagram, what is the pH at which pepsin would exhibit the most activity?

In an experiment, a small amount of allosteric inhibitor is added to tube A and no inhibitor is added to tube B.The full reaction is completed in tube B twice as quickly as it is completed in tube A.The allosteric inhibitor acted by

Which action would reverse the effects of a competitive inhibitor on an enzyme but not the effects of a noncompetitive or an irreversible inhibitor?

Living things use chemical reactions to live, grow, and reproduce.Chemical reactions are accompanied by energy changes.Which term refers to the topic of energy change in chemical reactions?

A reaction with a G of ‒14.3 kcal/mol releases energy that is then used by a second reaction with a G of +10.2 kcal/mol.The net free energy change of the coupled reactions is _______.

Certain types of cells have very low levels of metabolic activity for long time periods, but then rapidly shift to grow and divide.To undergo this shift, these cells must activate anabolic pathways.Which is one way they are able to accomplish this?