MCAT Official Prep Free Practice Exam
(Scored) – Active Latest Exam Questions
and Answers, A+ Guarantee 2026
What quantity of Compound 1 must be provided to prepare
100.00 mL of solution with a concentration equal to Ki? Ki =
60.3 μM
A.48.4 mg
B.24.2 mg
C. 5.64 mg
D. 2.92 mg - Correct Answers ✅In 100.00 mL solution, 60.3
μM Compound 1 contains 6.03 μmol, which when converted
to mol and multiplied by the molar mass, yields 0.00292 g or
2.92 mg.
If only [I] is increased, then [ESI] or [EI] increases. This is an
example of:
A.
the Bose-Einstein Principle.
B.
the Heisenberg Uncertainty Principle.
C.
the Le Châtelier's Principle.
D.
the Pauli Exclusion Principle. - Correct Answers ✅Le
Châtelier's Principle states that in a reversible process, the
application of stress to the system will cause the system to
,MCAT Official Prep Free Practice Exam
(Scored) – Active Latest Exam Questions
and Answers, A+ Guarantee 2026
respond in a way that will relieve this stress. In this case, the
reversible process is E + I forming EI or ES + I forming ESI. In
either case, increasing [I] induces stress of the system, and
the system relieves that stress by converting I to either more
EI or ESI.
Which structural change to Compound 1 would make it more
water soluble?
A.
Replacing benzene CH with N in the ring
B.
Replacing C=O with C=CH2
C.
Replacing N-N=N with CH-CH=CH
D.
Replacing NH with NCH3 - Correct Answers ✅Nitrogen in
the benzene ring would have a lone pair that could accept a
hydrogen bond from water, thus increasing the solubility of
the compound.
In μM•s-1 and μM, what should the approximate values of
kcat/KM and Ki be, respectively, when [I] = 180 μM?
A.
33.5 and 15.7
,MCAT Official Prep Free Practice Exam
(Scored) – Active Latest Exam Questions
and Answers, A+ Guarantee 2026
B.
75 and 30.1
C.
150 and 60.3
D.
300 and 120.6 - Correct Answers ✅Based on the data in
Table 1, increasing [I] has no effect on kcat/KM, so it should
remain at 150 μM•s-1. Also, Ki is an equilibrium constant, so
it will not be affected by a change in [I].
What functional group transformation occurs in the product of
the reaction catalyzed by Na+-NQR?
A.
RC(=O)R → RCH(OH)R
B.
ROPO32- → ROH + Pi
C.
RC(=O)NHR'→ RCOOH + R'NH2
D.
RC(=O)OR'→ RCOOH + R'OH - Correct Answers ✅This is
two-electron reduction of a ketone to an alcohol, which is the
reaction catalyzed by Na+-NQR.
, MCAT Official Prep Free Practice Exam
(Scored) – Active Latest Exam Questions
and Answers, A+ Guarantee 2026
What is the ratio of cation to enzyme in the
spectroelectrochemical experiments described in the
passage?
A.
1:2
B.
2:1
C.
20:1
D.
200:1 - Correct Answers ✅The ratio can be found by noting
that the enzyme concentration was 0.75 mM, while the
concentration of cations was 0.150 M = 150 mM. The ratio is
therefore 200:1.
The reaction between NADH and ubiquinone is exergonic, but
the reaction, when catalyzed by Na+-NQR, does not generate
much heat in vivo. What factor accounts for this difference?
The reaction catalyzed by Na+-NQR in vivo:
A.
is more exothermic as a result of the lower activation energy.
B.
occurs sequentially in several small steps.
C.
(Scored) – Active Latest Exam Questions
and Answers, A+ Guarantee 2026
What quantity of Compound 1 must be provided to prepare
100.00 mL of solution with a concentration equal to Ki? Ki =
60.3 μM
A.48.4 mg
B.24.2 mg
C. 5.64 mg
D. 2.92 mg - Correct Answers ✅In 100.00 mL solution, 60.3
μM Compound 1 contains 6.03 μmol, which when converted
to mol and multiplied by the molar mass, yields 0.00292 g or
2.92 mg.
If only [I] is increased, then [ESI] or [EI] increases. This is an
example of:
A.
the Bose-Einstein Principle.
B.
the Heisenberg Uncertainty Principle.
C.
the Le Châtelier's Principle.
D.
the Pauli Exclusion Principle. - Correct Answers ✅Le
Châtelier's Principle states that in a reversible process, the
application of stress to the system will cause the system to
,MCAT Official Prep Free Practice Exam
(Scored) – Active Latest Exam Questions
and Answers, A+ Guarantee 2026
respond in a way that will relieve this stress. In this case, the
reversible process is E + I forming EI or ES + I forming ESI. In
either case, increasing [I] induces stress of the system, and
the system relieves that stress by converting I to either more
EI or ESI.
Which structural change to Compound 1 would make it more
water soluble?
A.
Replacing benzene CH with N in the ring
B.
Replacing C=O with C=CH2
C.
Replacing N-N=N with CH-CH=CH
D.
Replacing NH with NCH3 - Correct Answers ✅Nitrogen in
the benzene ring would have a lone pair that could accept a
hydrogen bond from water, thus increasing the solubility of
the compound.
In μM•s-1 and μM, what should the approximate values of
kcat/KM and Ki be, respectively, when [I] = 180 μM?
A.
33.5 and 15.7
,MCAT Official Prep Free Practice Exam
(Scored) – Active Latest Exam Questions
and Answers, A+ Guarantee 2026
B.
75 and 30.1
C.
150 and 60.3
D.
300 and 120.6 - Correct Answers ✅Based on the data in
Table 1, increasing [I] has no effect on kcat/KM, so it should
remain at 150 μM•s-1. Also, Ki is an equilibrium constant, so
it will not be affected by a change in [I].
What functional group transformation occurs in the product of
the reaction catalyzed by Na+-NQR?
A.
RC(=O)R → RCH(OH)R
B.
ROPO32- → ROH + Pi
C.
RC(=O)NHR'→ RCOOH + R'NH2
D.
RC(=O)OR'→ RCOOH + R'OH - Correct Answers ✅This is
two-electron reduction of a ketone to an alcohol, which is the
reaction catalyzed by Na+-NQR.
, MCAT Official Prep Free Practice Exam
(Scored) – Active Latest Exam Questions
and Answers, A+ Guarantee 2026
What is the ratio of cation to enzyme in the
spectroelectrochemical experiments described in the
passage?
A.
1:2
B.
2:1
C.
20:1
D.
200:1 - Correct Answers ✅The ratio can be found by noting
that the enzyme concentration was 0.75 mM, while the
concentration of cations was 0.150 M = 150 mM. The ratio is
therefore 200:1.
The reaction between NADH and ubiquinone is exergonic, but
the reaction, when catalyzed by Na+-NQR, does not generate
much heat in vivo. What factor accounts for this difference?
The reaction catalyzed by Na+-NQR in vivo:
A.
is more exothermic as a result of the lower activation energy.
B.
occurs sequentially in several small steps.
C.
