MCAT Practice Multiple
Choices Current Questions with
Latest 2025-2026 Correct
Answers GRADED A+
1. Why are triacylglycerols used in the human body for energy storage?
A) They are highly hydrated, and therefore can store lots of energy.
B) They always have short fatty acid chains, for easy access by metabolic
enzymes.
C) The carbon atoms of the fatty acid chains are highly reduced, and
therefore yield more energy upon oxidation.
D) Polysaccharides, which would actually be a better energy storage form,
would dissolve in the body.
- ANS - C
Triacylglycerols are highly hydrophobic and therefore not highly
hydrated (which would add extra weight from the water of hydration,
taking away from the energy density of these molecules), eliminating
choice (A). The fatty acid chains produce twice as much energy as
polysaccharides during oxidation because they are highly reduced. The
fatty acid chains vary in length and saturation.
, 2. Action potentials travel down neural axons that resist the flow of
current. In considering a theoretical circuit, one normally assumes that
the wire has no resistivity. In the real world, however, wire resistivity is
an important consideration. Which of the following is a way to increase
resistance?
A) Lengthen the wire
B) Widen the wire
C) Lower the temperature
D) Change from tungsten to copper wire
- ANS - A
This question tests your knowledge of resistance in wires. An electrical
wire's resistance is directly proportional to its length and inversely
proportional to its cross-sectional area. Think of it as gravel in a pipe—
the wider the pipe and the shorter the pipe, the easier it is for water to go
through it.
B is incorrect because when a wire's cross-sectional area is increased, its
resistivity is decreased.
C is incorrect because lowering temperature decreases resistivity. Think
superconductors.
D is incorrect because tungsten has higher resistivity than copper.
Tungsten is used for lightbulb filaments because of its higher resistivity.
Choices Current Questions with
Latest 2025-2026 Correct
Answers GRADED A+
1. Why are triacylglycerols used in the human body for energy storage?
A) They are highly hydrated, and therefore can store lots of energy.
B) They always have short fatty acid chains, for easy access by metabolic
enzymes.
C) The carbon atoms of the fatty acid chains are highly reduced, and
therefore yield more energy upon oxidation.
D) Polysaccharides, which would actually be a better energy storage form,
would dissolve in the body.
- ANS - C
Triacylglycerols are highly hydrophobic and therefore not highly
hydrated (which would add extra weight from the water of hydration,
taking away from the energy density of these molecules), eliminating
choice (A). The fatty acid chains produce twice as much energy as
polysaccharides during oxidation because they are highly reduced. The
fatty acid chains vary in length and saturation.
, 2. Action potentials travel down neural axons that resist the flow of
current. In considering a theoretical circuit, one normally assumes that
the wire has no resistivity. In the real world, however, wire resistivity is
an important consideration. Which of the following is a way to increase
resistance?
A) Lengthen the wire
B) Widen the wire
C) Lower the temperature
D) Change from tungsten to copper wire
- ANS - A
This question tests your knowledge of resistance in wires. An electrical
wire's resistance is directly proportional to its length and inversely
proportional to its cross-sectional area. Think of it as gravel in a pipe—
the wider the pipe and the shorter the pipe, the easier it is for water to go
through it.
B is incorrect because when a wire's cross-sectional area is increased, its
resistivity is decreased.
C is incorrect because lowering temperature decreases resistivity. Think
superconductors.
D is incorrect because tungsten has higher resistivity than copper.
Tungsten is used for lightbulb filaments because of its higher resistivity.
