MCAT EXAM AND PRACTICE EXAM NEWEST 2026/ 2027 | MEDICAL COLLEGE ADMISSION
TEST AAMC EXAM PRE QUESTIONS AND ANSWERS ALREADY GRADED A+| 100% VERIFIED
SOLUTIONS………...
CORE DOMAINS
Biological and Biochemical Foundations of Living Systems
Chemical and Physical Foundations of Biological Systems
Psychological, Social, and Biological Foundations of Behavior
Critical Analysis and Reasoning Skills
Scientific Inquiry and Reasoning Skills
Research Design and Data-Based Statistical Reasoning
Biomolecules and Cellular Processes
Human Body Systems and Homeostasis
Behavioral and Social Determinants of Health
Biochemistry and Molecular Biology
INTRODUCTION
This comprehensive examination is designed to evaluate the knowledge and critical reasoning skills
essential for success on the Medical College Admission Test. It assesses proficiency in biology,
biochemistry, general and organic chemistry, physics, psychology, and sociology, along with the
scientific inquiry and reasoning skills demanded by medical school curricula. The exam utilizes
,multiple-choice and scenario-based questions that simulate real-world scientific and clinical
reasoning. Emphasis is placed on applying foundational concepts to complex problems, analyzing
experimental data, and demonstrating critical thinking and decision-making under timed
conditions.
SECTION ONE: QUESTIONS 1–100
1. Which of the following best describes the primary function of the sodium-potassium pump in
maintaining the resting membrane potential of a neuron?
A. It transports three sodium ions out of the cell and two potassium ions into the cell,
contributing to a negative resting potential.
B. It transports two sodium ions out of the cell and three potassium ions into the cell,
contributing to a positive resting potential.
C. It transports sodium and potassium ions in equal amounts, maintaining electrical neutrality.
D. It transports chloride ions into the cell, hyperpolarizing the membrane.
🟢 A. It transports three sodium ions out of the cell and two potassium ions into the cell,
contributing to a negative resting potential.
🔴 RATIONALE: The sodium-potassium pump (Na+/K+-ATPase) moves three Na+ out and two
K+ in per ATP hydrolyzed. This electrogenic action contributes to the negative resting membrane
potential by removing more positive charge than it brings in.
2. A researcher is studying enzyme kinetics and observes that the reaction rate reaches a
maximum velocity (Vmax) at high substrate concentrations. Which of the following best
, explains this observation?
A. All enzyme active sites are saturated with substrate.
B. The enzyme undergoes denaturation at high substrate concentrations.
C. The substrate inhibits the enzyme through a feedback mechanism.
D. The enzyme's affinity for the substrate decreases as concentration increases.
🟢 A. All enzyme active sites are saturated with substrate.
🔴 RATIONALE: Vmax is reached when all available enzyme active sites are occupied by
substrate, meaning the enzyme is working at its maximum capacity and the reaction rate cannot
increase further.
3. Which of the following amino acids is most likely to be found in the interior of a globular
protein folded in an aqueous environment?
A. Lysine
B. Glutamic acid
C. Leucine
D. Arginine
🟢 C. Leucine
🔴 RATIONALE: Leucine is a nonpolar, hydrophobic amino acid. In an aqueous environment,
hydrophobic residues are typically buried in the interior of globular proteins to minimize contact
with water, while charged and polar residues are on the surface.
, 4. During glycolysis, which of the following enzymes catalyzes the rate-limiting step?
A. Hexokinase
B. Phosphofructokinase-1
C. Pyruvate kinase
D. Aldolase
🟢 B. Phosphofructokinase-1
🔴 RATIONALE: Phosphofructokinase-1 (PFK-1) catalyzes the conversion of fructose-6-
phosphate to fructose-1,6-bisphosphate. This is the committed and rate-limiting step of
glycolysis, regulated by ATP, AMP, and citrate.
5. A patient presents with a mutation in the gene encoding the LDL receptor. Which of the
following conditions is most likely to result?
A. Familial hypercholesterolemia
B. Cystic fibrosis
C. Phenylketonuria
D. Sickle cell anemia
🟢 A. Familial hypercholesterolemia
🔴 RATIONALE: A mutation in the LDL receptor gene causes familial hypercholesterolemia,
characterized by impaired clearance of LDL cholesterol from the bloodstream, leading to
elevated LDL levels and increased risk of atherosclerosis.
TEST AAMC EXAM PRE QUESTIONS AND ANSWERS ALREADY GRADED A+| 100% VERIFIED
SOLUTIONS………...
CORE DOMAINS
Biological and Biochemical Foundations of Living Systems
Chemical and Physical Foundations of Biological Systems
Psychological, Social, and Biological Foundations of Behavior
Critical Analysis and Reasoning Skills
Scientific Inquiry and Reasoning Skills
Research Design and Data-Based Statistical Reasoning
Biomolecules and Cellular Processes
Human Body Systems and Homeostasis
Behavioral and Social Determinants of Health
Biochemistry and Molecular Biology
INTRODUCTION
This comprehensive examination is designed to evaluate the knowledge and critical reasoning skills
essential for success on the Medical College Admission Test. It assesses proficiency in biology,
biochemistry, general and organic chemistry, physics, psychology, and sociology, along with the
scientific inquiry and reasoning skills demanded by medical school curricula. The exam utilizes
,multiple-choice and scenario-based questions that simulate real-world scientific and clinical
reasoning. Emphasis is placed on applying foundational concepts to complex problems, analyzing
experimental data, and demonstrating critical thinking and decision-making under timed
conditions.
SECTION ONE: QUESTIONS 1–100
1. Which of the following best describes the primary function of the sodium-potassium pump in
maintaining the resting membrane potential of a neuron?
A. It transports three sodium ions out of the cell and two potassium ions into the cell,
contributing to a negative resting potential.
B. It transports two sodium ions out of the cell and three potassium ions into the cell,
contributing to a positive resting potential.
C. It transports sodium and potassium ions in equal amounts, maintaining electrical neutrality.
D. It transports chloride ions into the cell, hyperpolarizing the membrane.
🟢 A. It transports three sodium ions out of the cell and two potassium ions into the cell,
contributing to a negative resting potential.
🔴 RATIONALE: The sodium-potassium pump (Na+/K+-ATPase) moves three Na+ out and two
K+ in per ATP hydrolyzed. This electrogenic action contributes to the negative resting membrane
potential by removing more positive charge than it brings in.
2. A researcher is studying enzyme kinetics and observes that the reaction rate reaches a
maximum velocity (Vmax) at high substrate concentrations. Which of the following best
, explains this observation?
A. All enzyme active sites are saturated with substrate.
B. The enzyme undergoes denaturation at high substrate concentrations.
C. The substrate inhibits the enzyme through a feedback mechanism.
D. The enzyme's affinity for the substrate decreases as concentration increases.
🟢 A. All enzyme active sites are saturated with substrate.
🔴 RATIONALE: Vmax is reached when all available enzyme active sites are occupied by
substrate, meaning the enzyme is working at its maximum capacity and the reaction rate cannot
increase further.
3. Which of the following amino acids is most likely to be found in the interior of a globular
protein folded in an aqueous environment?
A. Lysine
B. Glutamic acid
C. Leucine
D. Arginine
🟢 C. Leucine
🔴 RATIONALE: Leucine is a nonpolar, hydrophobic amino acid. In an aqueous environment,
hydrophobic residues are typically buried in the interior of globular proteins to minimize contact
with water, while charged and polar residues are on the surface.
, 4. During glycolysis, which of the following enzymes catalyzes the rate-limiting step?
A. Hexokinase
B. Phosphofructokinase-1
C. Pyruvate kinase
D. Aldolase
🟢 B. Phosphofructokinase-1
🔴 RATIONALE: Phosphofructokinase-1 (PFK-1) catalyzes the conversion of fructose-6-
phosphate to fructose-1,6-bisphosphate. This is the committed and rate-limiting step of
glycolysis, regulated by ATP, AMP, and citrate.
5. A patient presents with a mutation in the gene encoding the LDL receptor. Which of the
following conditions is most likely to result?
A. Familial hypercholesterolemia
B. Cystic fibrosis
C. Phenylketonuria
D. Sickle cell anemia
🟢 A. Familial hypercholesterolemia
🔴 RATIONALE: A mutation in the LDL receptor gene causes familial hypercholesterolemia,
characterized by impaired clearance of LDL cholesterol from the bloodstream, leading to
elevated LDL levels and increased risk of atherosclerosis.
