MCAT AAMC FULL PRACTICE TEST 2026
VERIFIED QUESTIONS AND DETAILED
ANSWERS GRADED A+
◉ C/P: Compared to the concentration of the proteasome, the
concentration of the substrate is larger by what factor?
"purified rabbit proteasome (2 nM) was incubated in the presence of
porphyrin...the reaction was initiated by addition of the peptide (100
uM)"
A) 5 × 101
B) 5 × 102
C) 5 × 103
D) 5 × 104. Answer: D) 5 × 104
The answer to this question is D. The proteasome was present at a
concentration of 2 × 10-9 M, while the substrate was present at 100 ×
10-6 M. The ratio of these two numbers is 5 × 104.
◉ sp2 hybridized. Answer: possess exactly one doubly bonded atom
,◉ C/P: 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?
Rate of reaction = 125 nM/s
A) 2.5 × 10-2 s-1
B) 1.3 × 102 s-1
C) 5.3 × 103 s-1
D) 7.0 × 105 s-1. Answer: A) 2.5 × 10-2 s-1
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.
◉ kcat, Vmax, [E]. Answer: kcat = Vmax/[E]
◉ C/P: 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. Answer: B) Excitation of bound
electrons
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.
◉ C/P: Four organic compounds: 2-butanone, n-pentane, propanoic acid,
and n-butanol, present as a mixture, are separated by column
chromatography using silica gel with benzene as the eluent. What is the
expected order of elution of these four organic compounds from first to
last?
A) n-Pentane → 2-butanone → n-butanol → propanoic acid
B) n-Pentane → n-butanol → 2-butanone → propanoic acid
C) Propanoic acid → n-butanol → 2-butanone → n-pentane
D) Propanoic acid → 2-butanone → n-butanol → n-pentane. Answer: A)
n-Pentane → 2-butanone → n-butanol → propanoic acid
The answer to this question is A. The four compounds have comparable
molecular weights, so the order of elution will depend on the polarity of
the molecule. Since silica gel serves as the stationary phase for the
experiment, increasing the polarity of the eluting molecule will increase
, its affinity for the stationary phase and increase the elution time
(decreased Rf).
◉ C/P: 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.. Answer: D) the time it takes for half of all the
radioactive nuclei to decay into their daughter nuclei.
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.
◉ C/P: A person is sitting in a chair. 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
VERIFIED QUESTIONS AND DETAILED
ANSWERS GRADED A+
◉ C/P: Compared to the concentration of the proteasome, the
concentration of the substrate is larger by what factor?
"purified rabbit proteasome (2 nM) was incubated in the presence of
porphyrin...the reaction was initiated by addition of the peptide (100
uM)"
A) 5 × 101
B) 5 × 102
C) 5 × 103
D) 5 × 104. Answer: D) 5 × 104
The answer to this question is D. The proteasome was present at a
concentration of 2 × 10-9 M, while the substrate was present at 100 ×
10-6 M. The ratio of these two numbers is 5 × 104.
◉ sp2 hybridized. Answer: possess exactly one doubly bonded atom
,◉ C/P: 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?
Rate of reaction = 125 nM/s
A) 2.5 × 10-2 s-1
B) 1.3 × 102 s-1
C) 5.3 × 103 s-1
D) 7.0 × 105 s-1. Answer: A) 2.5 × 10-2 s-1
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.
◉ kcat, Vmax, [E]. Answer: kcat = Vmax/[E]
◉ C/P: 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. Answer: B) Excitation of bound
electrons
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.
◉ C/P: Four organic compounds: 2-butanone, n-pentane, propanoic acid,
and n-butanol, present as a mixture, are separated by column
chromatography using silica gel with benzene as the eluent. What is the
expected order of elution of these four organic compounds from first to
last?
A) n-Pentane → 2-butanone → n-butanol → propanoic acid
B) n-Pentane → n-butanol → 2-butanone → propanoic acid
C) Propanoic acid → n-butanol → 2-butanone → n-pentane
D) Propanoic acid → 2-butanone → n-butanol → n-pentane. Answer: A)
n-Pentane → 2-butanone → n-butanol → propanoic acid
The answer to this question is A. The four compounds have comparable
molecular weights, so the order of elution will depend on the polarity of
the molecule. Since silica gel serves as the stationary phase for the
experiment, increasing the polarity of the eluting molecule will increase
, its affinity for the stationary phase and increase the elution time
(decreased Rf).
◉ C/P: 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.. Answer: D) the time it takes for half of all the
radioactive nuclei to decay into their daughter nuclei.
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.
◉ C/P: A person is sitting in a chair. 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
