MCAT EXAM AND PRACTICE EXAM NEWEST 2026/2027 TEST
BANK | MEDICAL COLLEGE ADMISSION TEST AAMC EXAM
PREP WITH COMPLETE 400 REAL EXAM QUESTIONS AND
CORRECT VERIFIED ANSWERS | ALREADY GRADED A+ (MOST
RECENT!!)]
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
• Biochemistry and Molecular Biology
• General and Organic Chemistry
• Physics and Mathematics
• Psychology and Sociology
• Cellular and Systems Biology
• Genetics and Evolution
Introduction
This comprehensive examination is designed to evaluate the knowledge and
critical thinking skills required for success on the Medical College Admission Test
(MCAT). It assesses competencies in biological and biochemical foundations,
chemical and physical foundations, psychological and social foundations, and
critical analysis and reasoning skills. The exam utilizes a multiple-choice and
passage-based structure to simulate the rigor of the actual AAMC MCAT.
Emphasis is placed on the application of scientific knowledge to solve problems,
analyze data, and evaluate hypotheses. This test bank mirrors the content
,coverage and difficulty level of the most recent MCAT administrations, ensuring
thorough preparation for medical school admission.
SECTION ONE: QUESTIONS 1–200
1. Which of the following best describes the mechanism by which a
noncompetitive inhibitor decreases the rate of an enzyme-catalyzed reaction?
A. It binds to the active site and prevents substrate binding.
B. It binds to an allosteric site and changes the conformation of the active site.
C. It increases the Km of the enzyme for its substrate.
D. It decreases the Vmax of the enzyme.
Correct answer: B
RATIONALE: A noncompetitive inhibitor binds to a site other than the active
site (allosteric site), causing a conformational change that reduces the enzyme's
catalytic activity. This decreases Vmax while Km remains unchanged. Competitive
inhibitors bind to the active site and increase Km.
2. A researcher is studying a bacterial operon that is repressed in the presence
of glucose. This phenomenon is best explained by which of the following?
A. Catabolite repression
B. Induction
C. Attenuation
D. Feedback inhibition
Correct answer: A
RATIONALE: Catabolite repression occurs when glucose is present, reducing
cAMP levels and preventing CAP activation, thereby repressing operons involved
in alternative sugar metabolism, such as the lac operon.
3. Which of the following statements best describes the role of the sodium-
potassium pump in maintaining the resting membrane potential of a neuron?
A. It pumps 3 Na+ out and 2 K+ in, contributing to a negative interior.
B. It pumps 2 Na+ out and 3 K+ in, contributing to a positive interior.
C. It pumps equal amounts of Na+ and K+ in opposite directions.
D. It is not involved in maintaining resting membrane potential.
Correct answer: A
, RATIONALE: The Na+/K+ ATPase pumps 3 sodium ions out of the cell and 2
potassium ions into the cell, contributing to the negative resting membrane
potential.
4. In a population in Hardy-Weinberg equilibrium, the frequency of the recessive
allele is 0.3. What is the frequency of heterozygous individuals?
A. 0.09
B. 0.21
C. 0.42
D. 0.49
Correct answer: C
RATIONALE: If q = 0.3, then p = 0.7. The frequency of heterozygotes is 2pq =
2(0.7)(0.3) = 0.42.
5. Which of the following is the primary function of the Krebs cycle?
A. To produce ATP through substrate-level phosphorylation only
B. To generate NADH and FADH2 for the electron transport chain
C. To convert glucose to pyruvate
D. To synthesize fatty acids
Correct answer: B
RATIONALE: The Krebs cycle oxidizes acetyl-CoA to produce NADH, FADH2,
and GTP. The NADH and FADH2 then donate electrons to the electron transport
chain for ATP production.
6. A patient presents with a mutation in the CFTR gene. Which of the following
is the most likely consequence of this mutation?
A. Increased chloride transport across epithelial membranes
B. Decreased chloride transport, leading to thick mucus secretions
C. Increased sodium reabsorption in the kidneys
D. Decreased potassium secretion in the colon
Correct answer: B
RATIONALE: Mutations in the CFTR gene impair chloride transport, leading to
thick, viscous mucus secretions characteristic of cystic fibrosis.
, 7. Which of the following best describes the relationship between the
wavelength of light and the energy of a photon?
A. Energy is directly proportional to wavelength.
B. Energy is inversely proportional to wavelength.
C. Energy is independent of wavelength.
D. Energy is proportional to the square of the wavelength.
Correct answer: B
RATIONALE: According to Planck's equation, E = hc/λ, energy is inversely
proportional to wavelength. Shorter wavelengths have higher energy photons.
8. A researcher is investigating the effect of temperature on enzyme activity.
Which of the following is most likely to occur at extremely high temperatures?
A. Enzyme activity increases indefinitely.
B. Enzyme activity decreases due to denaturation.
C. Enzyme activity remains constant.
D. Enzyme activity decreases due to decreased substrate affinity.
Correct answer: B
RATIONALE: At extremely high temperatures, enzymes undergo denaturation,
losing their tertiary structure and catalytic function.
9. Which of the following is the correct order of the stages of mitosis?
A. Prophase, Metaphase, Anaphase, Telophase
B. Prophase, Anaphase, Metaphase, Telophase
C. Metaphase, Prophase, Anaphase, Telophase
D. Telophase, Anaphase, Metaphase, Prophase
Correct answer: A
RATIONALE: The correct sequence is Prophase, Metaphase, Anaphase, and
Telophase (PMAT).
10. In a cross between two heterozygous individuals (Aa x Aa), what is the
probability of producing an offspring with the recessive phenotype?
A. 0%
B. 25%
C. 50%
D. 75%
BANK | MEDICAL COLLEGE ADMISSION TEST AAMC EXAM
PREP WITH COMPLETE 400 REAL EXAM QUESTIONS AND
CORRECT VERIFIED ANSWERS | ALREADY GRADED A+ (MOST
RECENT!!)]
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
• Biochemistry and Molecular Biology
• General and Organic Chemistry
• Physics and Mathematics
• Psychology and Sociology
• Cellular and Systems Biology
• Genetics and Evolution
Introduction
This comprehensive examination is designed to evaluate the knowledge and
critical thinking skills required for success on the Medical College Admission Test
(MCAT). It assesses competencies in biological and biochemical foundations,
chemical and physical foundations, psychological and social foundations, and
critical analysis and reasoning skills. The exam utilizes a multiple-choice and
passage-based structure to simulate the rigor of the actual AAMC MCAT.
Emphasis is placed on the application of scientific knowledge to solve problems,
analyze data, and evaluate hypotheses. This test bank mirrors the content
,coverage and difficulty level of the most recent MCAT administrations, ensuring
thorough preparation for medical school admission.
SECTION ONE: QUESTIONS 1–200
1. Which of the following best describes the mechanism by which a
noncompetitive inhibitor decreases the rate of an enzyme-catalyzed reaction?
A. It binds to the active site and prevents substrate binding.
B. It binds to an allosteric site and changes the conformation of the active site.
C. It increases the Km of the enzyme for its substrate.
D. It decreases the Vmax of the enzyme.
Correct answer: B
RATIONALE: A noncompetitive inhibitor binds to a site other than the active
site (allosteric site), causing a conformational change that reduces the enzyme's
catalytic activity. This decreases Vmax while Km remains unchanged. Competitive
inhibitors bind to the active site and increase Km.
2. A researcher is studying a bacterial operon that is repressed in the presence
of glucose. This phenomenon is best explained by which of the following?
A. Catabolite repression
B. Induction
C. Attenuation
D. Feedback inhibition
Correct answer: A
RATIONALE: Catabolite repression occurs when glucose is present, reducing
cAMP levels and preventing CAP activation, thereby repressing operons involved
in alternative sugar metabolism, such as the lac operon.
3. Which of the following statements best describes the role of the sodium-
potassium pump in maintaining the resting membrane potential of a neuron?
A. It pumps 3 Na+ out and 2 K+ in, contributing to a negative interior.
B. It pumps 2 Na+ out and 3 K+ in, contributing to a positive interior.
C. It pumps equal amounts of Na+ and K+ in opposite directions.
D. It is not involved in maintaining resting membrane potential.
Correct answer: A
, RATIONALE: The Na+/K+ ATPase pumps 3 sodium ions out of the cell and 2
potassium ions into the cell, contributing to the negative resting membrane
potential.
4. In a population in Hardy-Weinberg equilibrium, the frequency of the recessive
allele is 0.3. What is the frequency of heterozygous individuals?
A. 0.09
B. 0.21
C. 0.42
D. 0.49
Correct answer: C
RATIONALE: If q = 0.3, then p = 0.7. The frequency of heterozygotes is 2pq =
2(0.7)(0.3) = 0.42.
5. Which of the following is the primary function of the Krebs cycle?
A. To produce ATP through substrate-level phosphorylation only
B. To generate NADH and FADH2 for the electron transport chain
C. To convert glucose to pyruvate
D. To synthesize fatty acids
Correct answer: B
RATIONALE: The Krebs cycle oxidizes acetyl-CoA to produce NADH, FADH2,
and GTP. The NADH and FADH2 then donate electrons to the electron transport
chain for ATP production.
6. A patient presents with a mutation in the CFTR gene. Which of the following
is the most likely consequence of this mutation?
A. Increased chloride transport across epithelial membranes
B. Decreased chloride transport, leading to thick mucus secretions
C. Increased sodium reabsorption in the kidneys
D. Decreased potassium secretion in the colon
Correct answer: B
RATIONALE: Mutations in the CFTR gene impair chloride transport, leading to
thick, viscous mucus secretions characteristic of cystic fibrosis.
, 7. Which of the following best describes the relationship between the
wavelength of light and the energy of a photon?
A. Energy is directly proportional to wavelength.
B. Energy is inversely proportional to wavelength.
C. Energy is independent of wavelength.
D. Energy is proportional to the square of the wavelength.
Correct answer: B
RATIONALE: According to Planck's equation, E = hc/λ, energy is inversely
proportional to wavelength. Shorter wavelengths have higher energy photons.
8. A researcher is investigating the effect of temperature on enzyme activity.
Which of the following is most likely to occur at extremely high temperatures?
A. Enzyme activity increases indefinitely.
B. Enzyme activity decreases due to denaturation.
C. Enzyme activity remains constant.
D. Enzyme activity decreases due to decreased substrate affinity.
Correct answer: B
RATIONALE: At extremely high temperatures, enzymes undergo denaturation,
losing their tertiary structure and catalytic function.
9. Which of the following is the correct order of the stages of mitosis?
A. Prophase, Metaphase, Anaphase, Telophase
B. Prophase, Anaphase, Metaphase, Telophase
C. Metaphase, Prophase, Anaphase, Telophase
D. Telophase, Anaphase, Metaphase, Prophase
Correct answer: A
RATIONALE: The correct sequence is Prophase, Metaphase, Anaphase, and
Telophase (PMAT).
10. In a cross between two heterozygous individuals (Aa x Aa), what is the
probability of producing an offspring with the recessive phenotype?
A. 0%
B. 25%
C. 50%
D. 75%
