AAMC MCAT EXAM 2025 LATEST EXAM
QUESTIONS AND CORRECT ANSWERS
(VERIFIED ANSWERS) WITH
RATIONALES | A+ GRADE
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. Correct Answer 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 Correct Answer 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.
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. Correct Answer
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 Correct
Answer 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."
A) hydrophilic
B) positively charged
C) negatively charged
D) hydrophobic Correct Answer 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 Correct Answer 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 Correct Answer B) sp2
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 Correct Answer C)
Hydrolysis of triacylglycerides
QUESTIONS AND CORRECT ANSWERS
(VERIFIED ANSWERS) WITH
RATIONALES | A+ GRADE
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. Correct Answer 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 Correct Answer 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.
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. Correct Answer
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 Correct
Answer 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."
A) hydrophilic
B) positively charged
C) negatively charged
D) hydrophobic Correct Answer 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 Correct Answer 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 Correct Answer B) sp2
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 Correct Answer C)
Hydrolysis of triacylglycerides
