1. Enzymes, pH, and equilibrium REVIEW GAME

2. Many names for enzymes end in the suffix A. acid B. ose C. ase D. hyde

3. Many names for enzymes end in the suffix A. acid B. ose C. ase D. hyde

4. What is the general function of enzymes within a cell?
A) to promote the synthesis of monomers
B) to induce chemical reactions
C) to stop chemical reactions
D) to speed up chemical reactions

5. What is the general function of enzymes within a cell?
A) to promote the synthesis of monomers
B) to induce chemical reactions
C) to stop chemical reactions
D) to speed up chemical reactions

6. A child is brought to the hospital with a fever of 107°F
A child is brought to the hospital with a fever of 107°F. Doctors immediately order an ice bath to lower the child's temperature. Which of the following statements offers the most logical explanation for this action?
Elevated body temperature will increase reaction rates in the child's cells and overload the limited number of enzymes found in the cell.
B) Elevated body temperatures may denature enzymes. This would interfere with the cell's abilities to catalyze various reactions.
C) Elevated body temperatures will increase the energy of activation needed to start various chemical reactions in the body. This will interfere with the ability of enzymes to catalyze vital chemical reactions.
D) Elevated body temperatures cause molecules to vibrate more quickly and prevent enzymes from easily attaching to reactants. This would slow vital body reactions.

7. A child is brought to the hospital with a fever of 107°F
A child is brought to the hospital with a fever of 107°F. Doctors immediately order an ice bath to lower the child's temperature. Which of the following statements offers the most logical explanation for this action?
Elevated body temperature will increase reaction rates in the child's cells and overload the limited number of enzymes found in the cell.
B) Elevated body temperatures may denature enzymes. This would interfere with the cell's abilities to catalyze various reactions.
C) Elevated body temperatures will increase the energy of activation needed to start various chemical reactions in the body. This will interfere with the ability of enzymes to catalyze vital chemical reactions.
D) Elevated body temperatures cause molecules to vibrate more quickly and prevent enzymes from easily attaching to reactants. This would slow vital body reactions.

8. The chemical reaction below depicts the hydrolysis of the disaccharide sucrose into two monosaccharides as catalyzed by the enzyme sucrase.
Sucrose --> Fructose + Glucose.
What is/are the “substrate” for this reaction
A) Sucrose
B) Sucrase
C) Fructose
D) Glucose
E) C and D

9. The chemical reaction below depicts the hydrolysis of the disaccharide sucrose into two monosaccharides as catalyzed by the enzyme sucrase.
Sucrose --> Fructose + Glucose.
What is/are the “substrate” for this reaction
A) Sucrose
B) Sucrase
C) Fructose
D) Glucose
E) C and D

10. The chemical reaction below depicts the hydrolysis of the disaccharide sucrose into two monosaccharides as catalyzed by the enzyme sucrase.
Sucrose --> Fructose + Glucose.
What is/are the “product” for this reaction
A) Sucrose
B) Sucrase
C) Fructose
D) Glucose
E) C and D

11. The chemical reaction below depicts the hydrolysis of the disaccharide sucrose into two monosaccharides as catalyzed by the enzyme sucrase.
Sucrose --> Fructose + Glucose.
What is/are the “product” for this reaction
A) Sucrose
B) Sucrase
C) Fructose
D) Glucose
E) C and D

12. Substrates bind to an enzyme's ________ site.
A) allosteric
B) inhibitory
C) phosphate
D) active

13. Substrates bind to an enzyme's ________ site.
A) allosteric
B) inhibitory
C) phosphate
D) active

14. The effect of temperature on the relative rate of action of an enzyme is represented in the graph below. The optimum temperature for the action of this enzyme is approximately
a. 15◦C
b. 22◦C
c. 37◦C
d. 50◦C

15. The effect of temperature on the relative rate of action of an enzyme is represented in the graph below. The optimum temperature for the action of this enzyme is approximately
a. 15◦C
b. 22◦C
c. 37◦C
d. 50◦C

16.  Use the diagram below to answer the question.
Identify the parts involved.
A and B are enzymes and C is the substrate
C is the enzyme and A and B are the substrates.
A is the enzyme, B is the monomer and C is the polymer
A and B are the substrates and C is the polymer

17.  Use the diagram below to answer the question.
Identify the parts involved.
A and B are enzymes and C is the substrate
C is the enzyme and A and B are the substrates.
A is the enzyme, B is the monomer and C is the polymer
A and B are the substrates and C is the polymer

18. The enzyme salivary amylase will act on starch but not on protein
The enzyme salivary amylase will act on starch but not on protein. This action illustrates that salivary amylase
A. contains starch
B. is not reusable
C. is substrate specific
D. lacks protein

19. The enzyme salivary amylase will act on starch but not on protein
The enzyme salivary amylase will act on starch but not on protein. This action illustrates that salivary amylase
A. contains starch
B. is not reusable
C. is substrate specific
D. lacks protein

20. A person may become lactose intolerant if their intestinal glands do not produce enough
A. maltase enzyme
B. lactase enzyme
C. lactose enzyme
D. maltose enzyme

21. A person may become lactose intolerant if their intestinal glands do not produce enough
A. maltase enzyme
B. lactase enzyme
C. lactose enzyme
D. maltose enzyme

22. When an enzyme catalyzes a reaction,
A) it lowers the activation energy of the reaction.
B) it raises the activation energy of the reaction.
C) it acts as a reactant.
D) it is used once and discarded.

23. When an enzyme catalyzes a reaction,
A) it lowers the activation energy of the reaction.
B) it raises the activation energy of the reaction.
C) it acts as a reactant.
D) it is used once and discarded.

24. Which of the following statements regarding enzymes is true?
A) Enzymes are inorganic.
B) An enzyme's function is unaffected by changes in pH.
C) Enzymes catalyze specific reactions.
D) Enzymes slow down the rate of a chemical reaction.

25. Which of the following statements regarding enzymes is true?
A) Enzymes are inorganic.
B) An enzyme's function is unaffected by changes in pH.
C) Enzymes catalyze specific reactions.
D) Enzymes slow down the rate of a chemical reaction.

26. Heating inactivates enzymes by
A) breaking the covalent bonds that hold the molecule together.
B) removing phosphate groups from the enzyme.
C) causing enzyme molecules to stick together.
D) changing the enzyme's three-dimensional shape.

27. Heating inactivates enzymes by
A) breaking the covalent bonds that hold the molecule together.
B) removing phosphate groups from the enzyme.
C) causing enzyme molecules to stick together.
D) changing the enzyme's three-dimensional shape.

28. The active site of an enzyme is
A) the region of a substrate that is changed by an enzyme.
B) the highly changeable portion of an enzyme that adapts to fit the substrates of various reactions.
C) the region of an enzyme that attaches to a substrate.
D) the region of a product that detaches from the enzyme.

29. The active site of an enzyme is
A) the region of a substrate that is changed by an enzyme.
B) the highly changeable portion of an enzyme that adapts to fit the substrates of various reactions.
C) the region of an enzyme that attaches to a substrate.
D) the region of a product that detaches from the enzyme.

30. Which of the following characteristics of protein will remain intact if the protein is denatured?
A) the shape of the protein
B) the function of the protein
C) the number of amino acids in the protein
D) the binding properties of the protein

31. Which of the following characteristics of protein will remain intact if the protein is denatured?
A) the shape of the protein
B) the function of the protein
C) the number of amino acids in the protein
D) the binding properties of the protein

32. The shape of the _______________ on the enzyme determines to which ___________________ the enzyme can bind.
active area; substrate
active site; product
loading dock; organelle
active site; substrate

33. The shape of the _______________ on the enzyme determines to which ___________________ the enzyme can bind.
active site; substrate

34. There are many different enzymes located in a single cell
There are many different enzymes located in a single cell. Why do enzymes catalyze a specific reaction?
Most enzymes can catalyze many different reactions.
The shape of the enzyme’s active site determines to which substrate the particular enzyme can bind.
Enzymes are transported to specific substrates (reactants) by ribosomes.

35. There are many different enzymes located in a single cell
There are many different enzymes located in a single cell. Why do enzymes catalyze a specific reaction? .
The shape of the enzyme’s active site determines to which substrate the particular enzyme can bind.

36. List TWO environmental factors that affect the reaction rate of an enzyme:
_____________________

37. List TWO environmental factors that affect the reaction rate of an enzyme:pH
TEMPERATURE
CONCENTRATION OF SUBSTRATE
CONCENTRATION OF ENZYME
SALT CONCENTRATION

38. When an enzyme has become misfolded or unfolded and can no longer perform it’s function, we say that the enzyme is
“_____________________.”  

39. When an enzyme has become misfolded or unfolded and can no longer perform it’s function, we say that the enzyme is
“DENATURED.”  

40. List TWO environmental factors that tend to denature enzymes:
_____________________

41. List TWO environmental factors that tend to denature enzymes:
Changes in pH
INCREASE IN TEMPERATURE
Changes in SALT CONCENTRATION

42. Which of the following statements about enzymes is false?
A) They increase the rate of chemical reactions.
B) They function as chemical catalysts.
C) They regulate virtually all chemical reactions in a cell.
D) They are monomers used to build proteins.

43. Which of the following statements about enzymes is false?
A) They increase the rate of chemical reactions.
B) They function as chemical catalysts.
C) They regulate virtually all chemical reactions in a cell.
D) They are monomers used to build proteins.

44. When you add acid to a solution, _____.
the hydrogen ion concentration increases and lowers the pH  
the hydrogen ion concentration decreases and raises the pH  
the hydrogen ion concentration increases and raises the pH  
the hydrogen ion concentration decreases and lowers the pH

45. When you add acid to a solution, _____.
the hydrogen ion concentration increases and lowers the pH  
the hydrogen ion concentration decreases and raises the pH  
the hydrogen ion concentration increases and raises the pH  
the hydrogen ion concentration decreases and lowers the pH

46. Grapefruit juice is approximately pH 3, and tomato juice is approximately pH 4. A glass of grapefruit juice contains _____ H+ as a glass of tomato juice.
half as much  
ten times as much  
one-tenth as much  
twice as much

47. Grapefruit juice is approximately pH 3, and tomato juice is approximately pH 4. A glass of grapefruit juice contains _____ H+ as a glass of tomato juice.
half as much  
ten times as much  
one-tenth as much  
twice as much

48. A pH of 6 is how many times more acidic than a pH of 9?
3  
100  
300
1,000

49. A pH of 6 is how many times more acidic than a pH of 9?
3  
100  
300
1,000

50. An acid is _____.
a solution with a pH between 7 and 14  
a material that resists pH changes  
any compound that accepts hydrogen ions  
a compound that donates hydrogen ions to a solution

51. An acid is _____.
a solution with a pH between 7 and 14  
a material that resists pH changes  
any compound that accepts hydrogen ions  
a compound that donates hydrogen ions to a solution

52. Adding a base tends to _____ of a solution.
increase the hydrogen ion concentration and increase the pH  
lower hydrogen ion concentration and increase the pH  
lower hydrogen ion concentration and lower the pH  
increase hydrogen ion concentration and lower the pH

53. Adding a base tends to _____ of a solution.
increase the hydrogen ion concentration and increase the pH  
lower hydrogen ion concentration and increase the pH  
lower hydrogen ion concentration and lower the pH  
increase hydrogen ion concentration and lower the pH

54. Which of the following statements about pH is true?
A) The pH scale is a measure of oxygen ion concentration.
B) A single unit change on the pH scale is equivalent to a 1% change in hydrogen ion concentration.
C) An increase in hydrogen ion concentration means a decrease in pH scale units.
D) Basic pH levels are less than 7.

55. Which of the following statements about pH is true?
A) The pH scale is a measure of oxygen ion concentration.
B) A single unit change on the pH scale is equivalent to a 1% change in hydrogen ion concentration.
C) An increase in hydrogen ion concentration means a decrease in pH scale units.
D) Basic pH levels are less than 7.

56. In the following reaction:
HCO3- (aq) + H2O (aq) → H2CO3 (aq) + OH- (aq)
A) HCO3- is an acid and H2CO3 is its conjugate base.
B) H2O is an acid and OH- is its conjugate base.
C) HCO3- is an acid and OH- is its conjugate base.
D) H2O is an acid and H2CO3 is its conjugate base.
E) H2O is an acid and HCO3- is its conjugate base.

57. In the following reaction:
HCO3- (aq) + H2O (aq) → H2CO3 (aq) + OH- (aq)
A) HCO3- is an acid and H2CO3 is its conjugate base.
B) H2O is an acid and OH- is its conjugate base.
C) HCO3- is an acid and OH- is its conjugate base.
D) H2O is an acid and H2CO3 is its conjugate base.
E) H2O is an acid and HCO3- is its conjugate base.

58. Which of the following is NOT an acid-base conjugate pair?
A) H2CO3 and HCO3-
B) H2O and OH-
C) H2S and OH-
D) NH4+ and NH3

59. Which of the following is NOT an acid-base conjugate pair?
A) H2CO3 and HCO3-
B) H2O and OH-
C) H2S and OH-
D) NH4+ and NH3

60. What is the concentration of the hydrogen ions, [H+], in an acidic solution?
A) 0.0 M
B) 1.0 × 10-7 M
C) 1.0 × M
D) > 1.0× 10-7 M
E) < 1.0× 10-7 M

61. What is the concentration of the hydrogen ions, [H+], in an acidic solution?
A) 0.0 M
B) 1.0 × 10-7 M
C) 1.0 × M
D) > 1.0× 10-7 M
E) < 1.0× 10-7 M

62. What is the concentration of the hydroxide ions, [OH-], in an acidic solution?
A) 0.0 M
B) 1.0 × 10-7 M
C) 1.0 × M
D) > 1.0× 10-7 M
E) < 1.0× 10-7 M

63. What is the concentration of the hydroxide ions, [OH-], in an acidic solution?
A) 0.0 M
B) 1.0 × 10-7 M
C) 1.0 × M
D) > 1.0× 10-7 M
E) < 1.0× 10-7 M

64. What is the concentration of the hydrogen ions, [H+], in a neutral solution?
A) 0.0 M
B) 1.0 × 10-7 M
C) 1.0 × M
D) > 1.0× 10-7 M
E) < 1.0× 10-7 M

65. What is the concentration of the hydrogen ions, [H+], in a neutral solution?
A) 0.0 M
B) 1.0 × 10-7 M
C) 1.0 × M
D) > 1.0× 10-7 M
E) < 1.0× 10-7 M

66. What is the concentration of hydroxide ions, [OH-], in an aqueous solution if the concentration of hydrogen ions, [H+], is 1 × 10-5 M?
A) 6.7 × M
B) 1.5 × 109 M
C) 1.0 × M
D) 1.0 × 10-9 M

67. What is the concentration of hydroxide ions, [OH-], in an aqueous solution if the concentration of hydrogen ions, [H+], is 1 × 10-5 M?
A) 6.7 × M
B) 1.5 × 109 M
C) 1.0 × M
D) 1.0 × 10-9 M

68. Which solution below has the highest concentration of hydroxide ions?
A) pH = 3.21
B) pH = 12.49
C) pH = 7.00
D) pH = 10.12
E) pH = 7.93

69. Which solution below has the highest concentration of hydroxide ions?
A) pH = 3.21
B) pH = 12.49
C) pH = 7.00
D) pH = 10.12
E) pH = 7.93

70. What is the pH of a solution that has a H⁺ concentration equal to 1
What is the pH of a solution that has a H⁺ concentration equal to 1.6 × 10-5 M?
A) 4.8
B) 5.2
C) 0.2
D) 10.2
E) none of the above

71. What is the pH of a solution that has a H⁺ concentration equal to 1
What is the pH of a solution that has a H⁺ concentration equal to 1.6 × 10-5 M?
A) 4.8
B) 5.2
C) 0.2
D) 10.2
E) none of the above

72. What is the hydrogen ion concentration, [H⁺], in a solution that has a pH of 11?
A) 1 × 103 M
B) 2.2 × 103 M
C) 1 × 10-3 M
D) 1 × M

73. What is the hydrogen ion concentration, [H⁺], in a solution that has a pH of 11?
A) 1 × 103 M
B) 2.2 × 103 M
C) 1 × 10-3 M
D) 1 × M

74. What is the hydrogen ion concentration, [H⁺], in a solution that has a pH of 3?
A) 1 × 103 M
B) 2.2 × 103 M
C) 1 × 10-3 M
D) 1 × M

75. What is the hydrogen ion concentration, [H⁺], in a solution that has a pH of 3?
A) 1 × 103 M
B) 2.2 × 103 M
C) 1 × 10-3 M
D) 1 × M

76. What is the hydroxide ion concentration, [OH-], in a solution that has a pH of 3?
A) 1 × 103 M
B) 2.2 × 103 M
C) 1 × 10-3 M
D) 1 × M

77. What is the hydroxide ion concentration, [OH-], in a solution that has a pH of 3?
A) 1 × 103 M
B) 2.2 × 103 M
C) 1 × 10-3 M
D) 1 × M

78. What is the hydroxide ion concentration, [OH-], in a solution that has a pH of 11?
A) 1 × 103 M
B) 2.2 × 103 M
C) 1 × 10-3 M
D) 1 × M

79. What is the hydroxide ion concentration, [OH-], in a solution that has a pH of 11?
A) 1 × 103 M
B) 2.2 × 103 M
C) 1 × 10-3 M
D) 1 × M

80. What is the pH of a solution with a hydrogen ion concentration, [H+], of 1 × 10-8 M
B) 4
C) 6
D) 8
E) 10

81. What is the pH of a solution with a hydrogen ion concentration, [H+], of 1 × 10-8 M
B) 4
C) 6
D) 8
E) 10

82. What is the pH of a solution with a hydroxide ion concentration, [OH-], of 1 × 10-8 M
B) 4
C) 6
D) 8
E) 10

83. What is the pH of a solution with a hydroxide ion concentration, [OH-], of 1 × 10-8 M
B) 4
C) 6
D) 8
E) 10

84. A chemical equilibrium exists when
A) reactants are completely changed to products.
B) there are equal amounts of reactants and products.
C) the rate at which reactants form products becomes zero.
D) the sum of reactant and product concentrations equals 1 M .
E) the rate at which reactants form products is the same as the rate at which products form reactants.

85. A chemical equilibrium exists when
A) reactants are completely changed to products.
B) there are equal amounts of reactants and products.
C) the rate at which reactants form products becomes zero.
D) the sum of reactant and product concentrations equals 1 M .
E) the rate at which reactants form products is the same as the rate at which products form reactants.

86. A system is said to be in dynamic equilibrium when:
A) there is no longer any net change in the concentrations of products or reactants.
B) the forward and reverse reactions come to a halt.
C) the sum of the concentrations of the reactants is equal to the sum of the concentrations of the products.
D) you have let the reaction proceed for approximately 30 minutes and can assume there will be no more changes.
E) none of the above

87. A system is said to be in dynamic equilibrium when:
A) there is no longer any net change in the concentrations of products or reactants.
B) the forward and reverse reactions come to a halt.
C) the sum of the concentrations of the reactants is equal to the sum of the concentrations of the products.
D) you have let the reaction proceed for approximately 30 minutes and can assume there will be no more changes.
E) none of the above

88. For the reaction aA + bB ⇌ cC + dD, the equilibrium expression is:

89. Keq = [C]c[D]d [A]a[B]b
For the reaction aA + bB ⇌ cC + dD, the equilibrium expression is:
Keq = [C]c[D]d
[A]a[B]b

90. Which of the following is TRUE for a system that is in dynamic equilibrium?
A) The forward reaction goes to 100% completion.
B) The reaction rate of the forward reaction approaches zero.
C) The concentration of products is equal to the concentration of the reactants.
D) Both the forward and reverse reactions come to a halt.
E) none of the above

91. Which of the following is TRUE for a system that is in dynamic equilibrium?
A) The forward reaction goes to 100% completion.
B) The reaction rate of the forward reaction approaches zero.
C) The concentration of products is equal to the concentration of the reactants.
D) Both the forward and reverse reactions come to a halt.
E) none of the above

92. What must be TRUE for a reaction possessing a large equilibrium constant?
A) The reaction rate is fast.
B) The reaction rate is slow.
C) The forward reaction is favored.
D) The reverse reaction is favored.

93. What must be TRUE for a reaction possessing a large equilibrium constant?
A) The reaction rate is fast.
B) The reaction rate is slow.
C) The forward reaction is favored.
D) The reverse reaction is favored.

94. For the reaction S2F6 ⇌ 2SF2 + F2 the equilibrium expression is:

95. S2F6 ⇌ 2SF2 + F2 Keq = [SF2]2[F2] [S2F6] For the reaction
the equilibrium expression is:
Keq = [SF2]2[F2]
[S2F6]

96. Which equilibrium constant represents a reaction that favors the formation of the products to the greatest extent?
A) Keq = 100
B) Keq = 1.0 ×108
C) Keq = 1.0 × 10-3
D) Keq = 1.0 ×10-18

97. Which equilibrium constant represents a reaction that favors the formation of the products to the greatest extent?
A) Keq = 100
B) Keq = 1.0 ×108
C) Keq = 1.0 × 10-3
D) Keq = 1.0 ×10-18

98. Which of the following is TRUE of a system for which Keq << 1?
A) It will take a long time to reach equilibrium.
B) It will take a short time to reach equilibrium.
C) The equilibrium favors the reverse reaction.
D) The equilibrium favors the forward reaction.

99. Which of the following is TRUE of a system for which Keq << 1?
A) It will take a long time to reach equilibrium.
B) It will take a short time to reach equilibrium.
C) The equilibrium favors the reverse reaction.
D) The equilibrium favors the forward reaction.

100. What chemical equation would generate the follow equilibrium expression?
Keq = [O2][N2]2
[N2O]2

101. Keq = [O2][N2]2 [N2O]2 2 N2O ⇌ O2 + 2 N2
What chemical equation would generate the follow equilibrium expression?
Keq = [O2][N2]2
[N2O]2
2 N2O ⇌ O N2

102. Which equilibrium constant represents a reaction that favors the formation of the reactants to the greatest extent?
A) Keq = 100
B) Keq = 1.0 ×108
C) Keq = 1.0 × 10-3
D) Keq = 1.0 ×10-18

103. Which equilibrium constant represents a reaction that favors the formation of the reactants to the greatest extent?
A) Keq = 100
B) Keq = 1.0 ×108
C) Keq = 1.0 × 10-3
D) Keq = 1.0 ×10-18

104. 2 N2O(g) ⇌ O2 (g) + 2 N2 (g). Consider the reaction:
Which of the following will cause a shift in the equilibrium to the left?
1. Remove N2O
2. Remove O2
3. Add N2
A) 1 and 2 only
B) 1 and 3 only
C) 2 and 3 only
D) All of 1, 2, and 3
E) Neither 1, 2, or 3

105. 2 N2O(g) ⇌ O2 (g) + 2 N2 (g). Consider the reaction:
Which of the following will cause a shift in the equilibrium to the left?
1. Remove N2O
2. Remove O2
3. Add N2
A) 1 and 2 only
B) 1 and 3 only
C) 2 and 3 only
D) All of 1, 2, and 3
E) Neither 1, 2, or 3

106. H2(g) + I2(g)  2HI(g). Consider the reaction:
Which of the following will cause a shift in the equilibrium to the right?
1. Remove H2
2. Remove 2 HI
3. Add I2
A) 1 and 2 only
B) 1 and 3 only
C) 2 and 3 only
D) All of 1, 2, and 3
E) Neither 1, 2, or 3

107. H2(g) + I2(g)  2HI(g). Consider the reaction:
Which of the following will cause a shift in the equilibrium to the right?
1. Remove H2
2. Remove 2 HI
3. Add I2
A) 1 and 2 only
B) 1 and 3 only
C) 2 and 3 only
D) All of 1, 2, and 3
E) Neither 1, 2, or 3