MCAT AAMC PRACTICE EXAM 2
Based on the data from Table 1, what effects do acid and chloride have on the
enzymatic activity of laccases?
A. Both acid and chloride decrease the activity.
B. Both acid and chloride increase the activity.
C. Acid decreases the activity, whereas chloride increases the activity.
D. Acid increases the activity, whereas chloride decreases the activity.
D.
This is a Biochemistry question that falls under the content category "Principles of
chemical thermodynamics and kinetics." The answer to this question is D. Activity
increased at lower pH, which corresponds to a higher acidity of the solution, while
introduction of chloride lowered activity dramatically. It is a Data-based and Statistical
Reasoning question because you must use data to explain the relationship between
activity and either acidity or chloride ion concentration.
The concentration of enzyme for each experiment was 5.0 μM. What is kcat for the
reaction at pH 4.5 with NO chloride added when Compound 3 is the substrate?
A. 2.5 × 10^–2 s–1
B. 1.3 × 10^2 s–1
C. 5.3 × 10^3 s–1
D. 7.0 × 10^5 s–1
A.
This is a Biochemistry question that falls under the content category “Principles of
chemical thermodynamics and kinetics.” The answer to this question is A. The fact that
the rate of product formation did not vary over time for the first 5 minutes implies that
the enzyme was saturated with substrate. Under these conditions, kcat = Vmax/[E] =
(125 nM/s)/5.0 μM = 2.5 × 10–2 s–1. It is a Scientific Reasoning and Problem Solving
question because you must determine and then use a scientific formula to solve a
problem.
,Absorption of ultraviolet light by organic molecules always results in what process?
A. Bond breaking
B. Excitation of bound electrons
C. Vibration of atoms in polar bonds
D. Ejection of bound electrons
B.
This is an Organic Chemistry question that falls under the content category "How light
and sound interact with matter." The answer to this question is B. The absorption of
ultraviolet light by organic molecules always results in electronic excitation. Bond
breaking can subsequently result, as can ionization or bond vibration, but none of these
processes are guaranteed to result from the absorption of ultraviolet light. It is a
Knowledge of Scientific Concepts and Principles question because you must recognize
a correct scientific principle.
The half-life of a radioactive material is:
A. half the time it takes for all of the radioactive nuclei to decay into radioactive nuclei.
B. half the time it takes for all of the radioactive nuclei to decay into their daughter
nuclei.
C. the time it takes for half of all the radioactive nuclei to decay into radioactive nuclei.
D. the time it takes for half of all the radioactive nuclei to decay into their daughter
nuclei.
D.
This is a Physics question that falls under the content category "Atoms, nuclear decay,
electronic structure, and atomic chemical behavior." The answer to this question is D
because the half-life of a radioactive material is defined as the time it takes for half of all
the radioactive nuclei to decay into their daughter nuclei, which may or may not also be
radioactive. It is a Knowledge of Scientific Concepts and Principles question because
the question requires recognizing correct scientific principles and related definitions.
A person is sitting on a chair as shown. Why must the person either lean forward or
slide their feet under the chair in order to stand up?
A. To increase the force required to stand up
B. To use the friction with the ground
C. To reduce the energy required to stand up
D. To keep the body in equilibrium while rising
D.
This is a Physics question that falls under the content category "Translational motion,
, forces, work, energy, and equilibrium in living systems." The answer to this question is D
because as the person is attempting to stand, the only support comes from the feet on
the ground. The person is in equilibrium only when the center of mass is directly above
their feet. Otherwise, if the person did not lean forward or slide the feet under the chair,
the person would fall backward due to the large torque created by the combination of
the weight of the body (applied at the person's center of mass) and the distance along
the horizontal between the center of mass and the support point. It is a Knowledge of
Scientific Concepts and Principles question because the question requires identifying
examples of observations that illustrate scientific principles.
What is the net charge of sT-loop at pH 7.2?
A. -2
B. -1
C. 0
D. +1
C.
This is an Organic Chemistry question that falls under the content category “Structure,
function, and reactivity of biologically-relevant molecules.” The answer to this question
is C because at pH 7.2, the N-terminus will be positively charged and the C-terminus
will be negatively charged. In addition, the lysine side chain will carry one positive
charge and the glutamic acid side chain will carry one negative charge. It is a Scientific
Reasoning and Problem Solving question because you must calculate a value based on
the scientific principle of amino acid charge to solve the problem.
In designing the experiment, the researchers used which type of 32P labeled ATP?
A. α32P-ATP
B. β32P-ATP
C. γ32P-ATP
D. δ32P-ATP
C.
This is a Biochemistry question that falls under the content category "Principles of
chemical thermodynamics and kinetics." The answer to this question is C because the
phosphoryl transfer from kinases comes from the γ-phosphate of ATP. Therefore, the
experiment should require γ32P-ATP. It is a Reasoning about the Design and Execution
of Research question because you must determine the correct way of conducting an
experiment to test the desired hypothesis.
Based on the data from Table 1, what effects do acid and chloride have on the
enzymatic activity of laccases?
A. Both acid and chloride decrease the activity.
B. Both acid and chloride increase the activity.
C. Acid decreases the activity, whereas chloride increases the activity.
D. Acid increases the activity, whereas chloride decreases the activity.
D.
This is a Biochemistry question that falls under the content category "Principles of
chemical thermodynamics and kinetics." The answer to this question is D. Activity
increased at lower pH, which corresponds to a higher acidity of the solution, while
introduction of chloride lowered activity dramatically. It is a Data-based and Statistical
Reasoning question because you must use data to explain the relationship between
activity and either acidity or chloride ion concentration.
The concentration of enzyme for each experiment was 5.0 μM. What is kcat for the
reaction at pH 4.5 with NO chloride added when Compound 3 is the substrate?
A. 2.5 × 10^–2 s–1
B. 1.3 × 10^2 s–1
C. 5.3 × 10^3 s–1
D. 7.0 × 10^5 s–1
A.
This is a Biochemistry question that falls under the content category “Principles of
chemical thermodynamics and kinetics.” The answer to this question is A. The fact that
the rate of product formation did not vary over time for the first 5 minutes implies that
the enzyme was saturated with substrate. Under these conditions, kcat = Vmax/[E] =
(125 nM/s)/5.0 μM = 2.5 × 10–2 s–1. It is a Scientific Reasoning and Problem Solving
question because you must determine and then use a scientific formula to solve a
problem.
,Absorption of ultraviolet light by organic molecules always results in what process?
A. Bond breaking
B. Excitation of bound electrons
C. Vibration of atoms in polar bonds
D. Ejection of bound electrons
B.
This is an Organic Chemistry question that falls under the content category "How light
and sound interact with matter." The answer to this question is B. The absorption of
ultraviolet light by organic molecules always results in electronic excitation. Bond
breaking can subsequently result, as can ionization or bond vibration, but none of these
processes are guaranteed to result from the absorption of ultraviolet light. It is a
Knowledge of Scientific Concepts and Principles question because you must recognize
a correct scientific principle.
The half-life of a radioactive material is:
A. half the time it takes for all of the radioactive nuclei to decay into radioactive nuclei.
B. half the time it takes for all of the radioactive nuclei to decay into their daughter
nuclei.
C. the time it takes for half of all the radioactive nuclei to decay into radioactive nuclei.
D. the time it takes for half of all the radioactive nuclei to decay into their daughter
nuclei.
D.
This is a Physics question that falls under the content category "Atoms, nuclear decay,
electronic structure, and atomic chemical behavior." The answer to this question is D
because the half-life of a radioactive material is defined as the time it takes for half of all
the radioactive nuclei to decay into their daughter nuclei, which may or may not also be
radioactive. It is a Knowledge of Scientific Concepts and Principles question because
the question requires recognizing correct scientific principles and related definitions.
A person is sitting on a chair as shown. Why must the person either lean forward or
slide their feet under the chair in order to stand up?
A. To increase the force required to stand up
B. To use the friction with the ground
C. To reduce the energy required to stand up
D. To keep the body in equilibrium while rising
D.
This is a Physics question that falls under the content category "Translational motion,
, forces, work, energy, and equilibrium in living systems." The answer to this question is D
because as the person is attempting to stand, the only support comes from the feet on
the ground. The person is in equilibrium only when the center of mass is directly above
their feet. Otherwise, if the person did not lean forward or slide the feet under the chair,
the person would fall backward due to the large torque created by the combination of
the weight of the body (applied at the person's center of mass) and the distance along
the horizontal between the center of mass and the support point. It is a Knowledge of
Scientific Concepts and Principles question because the question requires identifying
examples of observations that illustrate scientific principles.
What is the net charge of sT-loop at pH 7.2?
A. -2
B. -1
C. 0
D. +1
C.
This is an Organic Chemistry question that falls under the content category “Structure,
function, and reactivity of biologically-relevant molecules.” The answer to this question
is C because at pH 7.2, the N-terminus will be positively charged and the C-terminus
will be negatively charged. In addition, the lysine side chain will carry one positive
charge and the glutamic acid side chain will carry one negative charge. It is a Scientific
Reasoning and Problem Solving question because you must calculate a value based on
the scientific principle of amino acid charge to solve the problem.
In designing the experiment, the researchers used which type of 32P labeled ATP?
A. α32P-ATP
B. β32P-ATP
C. γ32P-ATP
D. δ32P-ATP
C.
This is a Biochemistry question that falls under the content category "Principles of
chemical thermodynamics and kinetics." The answer to this question is C because the
phosphoryl transfer from kinases comes from the γ-phosphate of ATP. Therefore, the
experiment should require γ32P-ATP. It is a Reasoning about the Design and Execution
of Research question because you must determine the correct way of conducting an
experiment to test the desired hypothesis.
