Fundamentals of Biochemistry Life at
the Molecular Level 5th Edition 2025
Brand NEW
____________________________________________________________________________________
A compound has a pKa of 7.4. To 100 mL of a 1.0 M solution of this compound at pH 8.0 is added 30
mL of 1.0 M hydrochloric acid. The resulting solution is pH:
A) 6.5
B) 6.8
C) 7.2
D) 7.4
E) 7.5
7.4
the henderson hasselbach equation
relates the pH of a solution to the pKa and the concentrations of acid and conjugate base.
Consider an acetate buffer, initially at the same pH as its pKa (4.76). When sodium hydroxide (NaOH)
is mixed with this buffer, the:
A) pH remains constant.
B) pH rises more than if an equal amount of NaOH is added to an acetate buffer initially at pH 6.76.
C) pH rises more than if an equal amount of NaOH is added to unbuffered water at pH 4.76.
D) ratio of acetic acid to sodium acetate in the buffer falls.
E) sodium acetate formed precipitates because it is less soluble than acetic acid.
ratio of acetic acid to sodium acetate in the buffer falls
a compound is known to have a free amino group with pka of 8.8, and one other ionizable groups with
a pka between 5 and 7. to 100 mL of a 0.2 M solution of this compound at pH 8.2 was added to a 40
ML solution of 0.2 M Hcl. the pkas of the second ionizable group is
5.6
the buffers are made by combining a 1 M solution of acetic acid with a 1M solution of sodium acetate
in the ratios below: which of these statements is true of the resulting buffers
ph of buffer 1 > ph of buffer 2 > ph of buffer 3
A 1.0 M solution of a compound with 2 ionizable groups (pKa's = 6.2 and 9.5; 100 mL total) has a pH of
6.8. If a biochemist adds 60 mL of 1.0 M HCl to this solution, the solution will change to pH:
,A) 5.60
B) 8.90
C) 9.13
D) 9.32
E) The pH cannot be determined from this information.
5.60
in which reaction does water not participate as a reactant
production of gaseous carbon dioxide from bicarbonate
which of the following properties of water does not contribute to the fitness of the aqueous
environment for living organisms
the very low molecular weight of water
One of the enzymes involved in glycolysis, aldolase, requires Zn2+ for catalysis. Under conditions of
zinc deficiency, when the enzyme may lack zinc, it would be referred to as the:
A) apoenzyme.
B) coenzyme.
C) holoenzyme.
D) prosthetic group.
E) substrate.
apoenzyme
which one of the following is not among the six internationally accepted classes of enzymes
polymerases
Enzymes are potent catalysts because they:
A) are consumed in the reactions they catalyze.
B) are very specific and can prevent the conversion of products back to substrates.
C) drive reactions to completion while other catalysts drive reactions to equilibrium.
D) increase the equilibrium constants for the reactions they catalyze.
E) lower the activation energy for the reactions they catalyze.
lower the activation energy for the reactions they catalyze
The role of an enzyme in an enzyme-catalyzed reaction is to:
A) bind a transition state intermediate, such that it cannot be converted back to substrate.
B) ensure that all of the substrate is converted to product.
C) ensure that the product is more stable than the substrate.
D) increase the rate at which substrate is converted into product.
E) make the free-energy change for the reaction more favorable.
, increase the rate at which substrate is converted into product
which one of the following statements is true of enzyme catalysts
They can increase the reaction rate for a given reaction by a thousand-fold or more.
which one of the following statements is true of enzyme catalysts
They lower the activation energy for the conversion of substrate to product.
Which of the following statements is false?
For S --> P, a catalyst shifts the reaction equilibrium to the right.
Enzymes differ from other catalysts in that only enzymes:
A) are not consumed in the reaction.
B) display specificity toward a single reactant.
C) fail to influence the equilibrium point of the reaction.
D) form an activated complex with the reactants.
E) lower the activation energy of the reaction catalyzed.
display specificity toward a single reactant.
the benefit of measuring the initial rate of a reaction Vo is that at the beginning of a reaction
changes in [S] are negligible, so [S] can be treated as a constant.
which of the following statements about a plot of Vo vs. [S] for an enzyme that follows michaelis-
mention kinetics is false
at very high [S], the velocity curve becomes a horizontal like that intersects the Y-axis at Km
Using this reaction, the rate of breakdown of the enzyme-substrate complex can be described by the
expression:
k-1 [ES] + k2 [ES].
The steady state assumption, as applied to enzyme kinetics, implies:
A) Km = Ks.
B) the enzyme is regulated.
C) the ES complex is formed and broken down at equivalent rates.
D) the Km is equivalent to the cellular substrate concentration.
E) the maximum velocity occurs when the enzyme is saturated.
the ES complex is formed and broken down at equivalent rates.
the most abundant molecule in the human body
H2O
during chemical evolution, small organic molecules condense to form more complex molecules called
the Molecular Level 5th Edition 2025
Brand NEW
____________________________________________________________________________________
A compound has a pKa of 7.4. To 100 mL of a 1.0 M solution of this compound at pH 8.0 is added 30
mL of 1.0 M hydrochloric acid. The resulting solution is pH:
A) 6.5
B) 6.8
C) 7.2
D) 7.4
E) 7.5
7.4
the henderson hasselbach equation
relates the pH of a solution to the pKa and the concentrations of acid and conjugate base.
Consider an acetate buffer, initially at the same pH as its pKa (4.76). When sodium hydroxide (NaOH)
is mixed with this buffer, the:
A) pH remains constant.
B) pH rises more than if an equal amount of NaOH is added to an acetate buffer initially at pH 6.76.
C) pH rises more than if an equal amount of NaOH is added to unbuffered water at pH 4.76.
D) ratio of acetic acid to sodium acetate in the buffer falls.
E) sodium acetate formed precipitates because it is less soluble than acetic acid.
ratio of acetic acid to sodium acetate in the buffer falls
a compound is known to have a free amino group with pka of 8.8, and one other ionizable groups with
a pka between 5 and 7. to 100 mL of a 0.2 M solution of this compound at pH 8.2 was added to a 40
ML solution of 0.2 M Hcl. the pkas of the second ionizable group is
5.6
the buffers are made by combining a 1 M solution of acetic acid with a 1M solution of sodium acetate
in the ratios below: which of these statements is true of the resulting buffers
ph of buffer 1 > ph of buffer 2 > ph of buffer 3
A 1.0 M solution of a compound with 2 ionizable groups (pKa's = 6.2 and 9.5; 100 mL total) has a pH of
6.8. If a biochemist adds 60 mL of 1.0 M HCl to this solution, the solution will change to pH:
,A) 5.60
B) 8.90
C) 9.13
D) 9.32
E) The pH cannot be determined from this information.
5.60
in which reaction does water not participate as a reactant
production of gaseous carbon dioxide from bicarbonate
which of the following properties of water does not contribute to the fitness of the aqueous
environment for living organisms
the very low molecular weight of water
One of the enzymes involved in glycolysis, aldolase, requires Zn2+ for catalysis. Under conditions of
zinc deficiency, when the enzyme may lack zinc, it would be referred to as the:
A) apoenzyme.
B) coenzyme.
C) holoenzyme.
D) prosthetic group.
E) substrate.
apoenzyme
which one of the following is not among the six internationally accepted classes of enzymes
polymerases
Enzymes are potent catalysts because they:
A) are consumed in the reactions they catalyze.
B) are very specific and can prevent the conversion of products back to substrates.
C) drive reactions to completion while other catalysts drive reactions to equilibrium.
D) increase the equilibrium constants for the reactions they catalyze.
E) lower the activation energy for the reactions they catalyze.
lower the activation energy for the reactions they catalyze
The role of an enzyme in an enzyme-catalyzed reaction is to:
A) bind a transition state intermediate, such that it cannot be converted back to substrate.
B) ensure that all of the substrate is converted to product.
C) ensure that the product is more stable than the substrate.
D) increase the rate at which substrate is converted into product.
E) make the free-energy change for the reaction more favorable.
, increase the rate at which substrate is converted into product
which one of the following statements is true of enzyme catalysts
They can increase the reaction rate for a given reaction by a thousand-fold or more.
which one of the following statements is true of enzyme catalysts
They lower the activation energy for the conversion of substrate to product.
Which of the following statements is false?
For S --> P, a catalyst shifts the reaction equilibrium to the right.
Enzymes differ from other catalysts in that only enzymes:
A) are not consumed in the reaction.
B) display specificity toward a single reactant.
C) fail to influence the equilibrium point of the reaction.
D) form an activated complex with the reactants.
E) lower the activation energy of the reaction catalyzed.
display specificity toward a single reactant.
the benefit of measuring the initial rate of a reaction Vo is that at the beginning of a reaction
changes in [S] are negligible, so [S] can be treated as a constant.
which of the following statements about a plot of Vo vs. [S] for an enzyme that follows michaelis-
mention kinetics is false
at very high [S], the velocity curve becomes a horizontal like that intersects the Y-axis at Km
Using this reaction, the rate of breakdown of the enzyme-substrate complex can be described by the
expression:
k-1 [ES] + k2 [ES].
The steady state assumption, as applied to enzyme kinetics, implies:
A) Km = Ks.
B) the enzyme is regulated.
C) the ES complex is formed and broken down at equivalent rates.
D) the Km is equivalent to the cellular substrate concentration.
E) the maximum velocity occurs when the enzyme is saturated.
the ES complex is formed and broken down at equivalent rates.
the most abundant molecule in the human body
H2O
during chemical evolution, small organic molecules condense to form more complex molecules called
