MCAT Practice Questions and
Answers 100% Verified Answers
100% Correct
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. - ANSWER - 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.
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 - ANSWER - 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.
Sexually reproducing species have a selective advantage over asexually
reproducing species, because sexual reproduction:
A) is more energy efficient.
B) creates novel genetic recombinations.
C) decreases the likelihood of mutations.
D) always decreases offspring survival rate. - ANSWER - B
The reason those species that reproduce sexually have a selective advantage is
because gene recombination is a given with every fertilization—two genetically
unique nuclei—the sperm nucleus and the egg nucleus--fuse to form an equally
genetically unique zygote. This is the main means of introducing phenotypic
variability into a population.
Pus is primarily composed of phagocytosed bacterial remnants. Which of the
following would you expect to find in a microscopic sample of pus?
A) Red blood cells, white blood cells, and platelets
B) Granulocytes, monocytes, and macrophages
C) Eosinophils, basophils, and neutrophils
D) Collagen, white blood cells, and calcium - ANSWER - B
Phagocytosis plays an important role in both the nonspecific and humoral response
to foreign pathogens. At the level of the skin, macrophages dwell in the connective
tissue surrounding the organs of the body. Neutrophils are recruited to the site of
entry and become part of the non-specific response to invading bacteria, working in
Answers 100% Verified Answers
100% Correct
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. - ANSWER - 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.
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 - ANSWER - 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.
Sexually reproducing species have a selective advantage over asexually
reproducing species, because sexual reproduction:
A) is more energy efficient.
B) creates novel genetic recombinations.
C) decreases the likelihood of mutations.
D) always decreases offspring survival rate. - ANSWER - B
The reason those species that reproduce sexually have a selective advantage is
because gene recombination is a given with every fertilization—two genetically
unique nuclei—the sperm nucleus and the egg nucleus--fuse to form an equally
genetically unique zygote. This is the main means of introducing phenotypic
variability into a population.
Pus is primarily composed of phagocytosed bacterial remnants. Which of the
following would you expect to find in a microscopic sample of pus?
A) Red blood cells, white blood cells, and platelets
B) Granulocytes, monocytes, and macrophages
C) Eosinophils, basophils, and neutrophils
D) Collagen, white blood cells, and calcium - ANSWER - B
Phagocytosis plays an important role in both the nonspecific and humoral response
to foreign pathogens. At the level of the skin, macrophages dwell in the connective
tissue surrounding the organs of the body. Neutrophils are recruited to the site of
entry and become part of the non-specific response to invading bacteria, working in
