AAMC MCAT Practice Exam 1
AAMC MCAT PRACTICE EXAM 1 NEWEST 2025/2026 COMPLETE
ALL 200 QUESTIONS AND CORRECT DETAILED ANSWERS
|ALREADY GRADED A+||ALREADY GRADED A+
Why is the velocity of blood flow slower in capillaries than in arteries?
A) Capillary walls are more elastic than arterial walls.
B) Capillaries have less resistance to blood flow than arteries.
C) The total cross-sectional area of capillaries exceeds that of arteries.
D) Blood pressure is higher in the capillaries than in arteries.
C) The total cross-sectional area of capillaries exceeds that of arteries.
A1v1 = A2v2
The answer to this question is C because the high number of capillaries in the
body means that the total cross-sectional area of these vessels is larger than any
other vessel type in the circulatory system. This causes the velocity of the blood to
decrease.
Which of the following types of orbitals of the central atom is involved in bonding
in octahedral compounds?
A) sp
B) sp3
C) p
D) d2 sp3
D) d2 sp3
The answer to this question is D because octahedral compounds have six σ bonds
and no lone pairs. According to valence bond theory, the central atom requires
the hybridization of six atomic orbitals, d2sp3.
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, AAMC MCAT Practice Exam 1
The term "ideal gas" refers to a gas for which certain assumptions have been
made. Which of the following is such an assumption?
A) The law PV = nRT^2 is strictly obeyed.
B) Intermolecular forces are infinitely large.
C) Individual molecular volume and intermolecular forces are negligible.
D) One gram-mole occupies a volume of 22.4 L at 25 degrees C and one
atmosphere pressure.
C) Individual molecular volume and intermolecular forces are negligible.
The answer to this question is C since a property of an "ideal" gas is that it is
composed of particles that have negligible volume and do not exert
intermolecular forces.
The production of a variety of opsins functions to:
"Additional opsin based receptors are expressed in specialized cone cells"
A) increase sensitivity to low light
B) enable the detection of different colors
C) ensure fast recovery of 11-cis retinal after exposure
D) increase refractive index of the eye lens
B) enable the detection of different colors
The answer to this question is B. The wavelength of light absorbed by a molecule
depends on its structure, and so the production of a variety of structurally related
opsins functions to enable the detection of different colors.
The environment of the retinal binding site is most likely:
"Rhodopsin is composed of opsin, a family of seven helix transmembrane
proteins, and a covalently attached coenzyme, retinal."
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, AAMC MCAT Practice Exam 1
A) hydrophilic
B) positively charged
C) negatively charged
D) hydrophobic
D) hydrophobic
The answer to this question is D because retinal is composed of mainly carbon and
hydrogen, making it largely hydrophobic.
The source of the phosphate groups that are added to rhodopsin is:
"Wild-type or variant rhodopsin was reconstituted with 11-cis-retinal and
phosphorylated by rhodopsin kinase in the presence of ATP before examining
arrestin binding"
A) arrestin
B) rhodopsin kinase
C) ATP
D) all-trans-retinol
C) ATP
The answer is C because the requirement of ATP for kinase activity implies the
phosphate groups come from ATP.
What are the hybridization states of the carbon atoms involved in the conversion
of trans to cis retinal?
A) sp
B) sp2
C) sp3
D) sp3d
B) sp2
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, AAMC MCAT Practice Exam 1
he answer to this question is B because the reacting carbon atoms are both
central to AX3 systems with 3 bonded atoms and no lone pairs. The preferred
geometry for such a system is trigonal planar and the hybridization scheme that
facilitates this geometry is sp2.
Which reaction is catalyzed by LipA?
A) ATP hydrolysis
B) Peptide bond cleavage
C) Hydrolysis of triacylglycerides
D) Transfer of carboxyl groups
C) Hydrolysis of triacylglycerides
The answer is C because the fact that LipA is a lipase, which means it must
hydrolyze fatty acids.
Compared to the wild-type LipA, what is the change in net charge in variant XI at
pH 7?
R33G
K112D
M134D
Y139C
I157M
A) +4
B) +3
C) -3
D) -4
D) -4
The answer is D because the amino acid substitutions replace amino acids with
4|Page
AAMC MCAT PRACTICE EXAM 1 NEWEST 2025/2026 COMPLETE
ALL 200 QUESTIONS AND CORRECT DETAILED ANSWERS
|ALREADY GRADED A+||ALREADY GRADED A+
Why is the velocity of blood flow slower in capillaries than in arteries?
A) Capillary walls are more elastic than arterial walls.
B) Capillaries have less resistance to blood flow than arteries.
C) The total cross-sectional area of capillaries exceeds that of arteries.
D) Blood pressure is higher in the capillaries than in arteries.
C) The total cross-sectional area of capillaries exceeds that of arteries.
A1v1 = A2v2
The answer to this question is C because the high number of capillaries in the
body means that the total cross-sectional area of these vessels is larger than any
other vessel type in the circulatory system. This causes the velocity of the blood to
decrease.
Which of the following types of orbitals of the central atom is involved in bonding
in octahedral compounds?
A) sp
B) sp3
C) p
D) d2 sp3
D) d2 sp3
The answer to this question is D because octahedral compounds have six σ bonds
and no lone pairs. According to valence bond theory, the central atom requires
the hybridization of six atomic orbitals, d2sp3.
1|Page
, AAMC MCAT Practice Exam 1
The term "ideal gas" refers to a gas for which certain assumptions have been
made. Which of the following is such an assumption?
A) The law PV = nRT^2 is strictly obeyed.
B) Intermolecular forces are infinitely large.
C) Individual molecular volume and intermolecular forces are negligible.
D) One gram-mole occupies a volume of 22.4 L at 25 degrees C and one
atmosphere pressure.
C) Individual molecular volume and intermolecular forces are negligible.
The answer to this question is C since a property of an "ideal" gas is that it is
composed of particles that have negligible volume and do not exert
intermolecular forces.
The production of a variety of opsins functions to:
"Additional opsin based receptors are expressed in specialized cone cells"
A) increase sensitivity to low light
B) enable the detection of different colors
C) ensure fast recovery of 11-cis retinal after exposure
D) increase refractive index of the eye lens
B) enable the detection of different colors
The answer to this question is B. The wavelength of light absorbed by a molecule
depends on its structure, and so the production of a variety of structurally related
opsins functions to enable the detection of different colors.
The environment of the retinal binding site is most likely:
"Rhodopsin is composed of opsin, a family of seven helix transmembrane
proteins, and a covalently attached coenzyme, retinal."
2|Page
, AAMC MCAT Practice Exam 1
A) hydrophilic
B) positively charged
C) negatively charged
D) hydrophobic
D) hydrophobic
The answer to this question is D because retinal is composed of mainly carbon and
hydrogen, making it largely hydrophobic.
The source of the phosphate groups that are added to rhodopsin is:
"Wild-type or variant rhodopsin was reconstituted with 11-cis-retinal and
phosphorylated by rhodopsin kinase in the presence of ATP before examining
arrestin binding"
A) arrestin
B) rhodopsin kinase
C) ATP
D) all-trans-retinol
C) ATP
The answer is C because the requirement of ATP for kinase activity implies the
phosphate groups come from ATP.
What are the hybridization states of the carbon atoms involved in the conversion
of trans to cis retinal?
A) sp
B) sp2
C) sp3
D) sp3d
B) sp2
3|Page
, AAMC MCAT Practice Exam 1
he answer to this question is B because the reacting carbon atoms are both
central to AX3 systems with 3 bonded atoms and no lone pairs. The preferred
geometry for such a system is trigonal planar and the hybridization scheme that
facilitates this geometry is sp2.
Which reaction is catalyzed by LipA?
A) ATP hydrolysis
B) Peptide bond cleavage
C) Hydrolysis of triacylglycerides
D) Transfer of carboxyl groups
C) Hydrolysis of triacylglycerides
The answer is C because the fact that LipA is a lipase, which means it must
hydrolyze fatty acids.
Compared to the wild-type LipA, what is the change in net charge in variant XI at
pH 7?
R33G
K112D
M134D
Y139C
I157M
A) +4
B) +3
C) -3
D) -4
D) -4
The answer is D because the amino acid substitutions replace amino acids with
4|Page
