MCAT Practice Exam – Biological & Biochemical
Foundations Exam Questions And Correct
Answers (Verified Answers) Plus Rationales
2025/2026 Q&A | Instant Download Pdf
1. Which organelle is primarily responsible for ATP production in
eukaryotic cells?
A) Nucleus
B) Golgi apparatus
C) Mitochondrion
D) Lysosome
The mitochondrion produces ATP via oxidative phosphorylation,
which is the primary energy currency for the cell.
2. Which of the following macromolecules contains nitrogen in its
structure?
A) Lipids
B) Proteins
C) Carbohydrates
D) Triglycerides
Proteins are composed of amino acids, which contain nitrogen in
their amino groups.
3. During glycolysis, one molecule of glucose is converted into:
A) Two molecules of pyruvate
B) Two molecules of pyruvate
C) Four molecules of ATP only
D) Lactic acid
,Glycolysis splits glucose (6C) into two pyruvate molecules (3C each),
producing a net of 2 ATP.
4. The functional unit of the kidney responsible for filtration is the:
A) Ureter
B) Nephron
C) Glomerulus only
D) Collecting duct
The nephron is the structural and functional unit of the kidney,
containing the glomerulus and tubules for filtration and reabsorption.
5. Which blood type is considered the universal donor?
A) AB+
B) O+
C) O-
D) AB-
O- blood lacks A, B, and Rh antigens, making it compatible with all
recipient blood types.
6. In skeletal muscle, contraction is initiated by:
A) Calcium binding to tropomyosin
B) Calcium binding to troponin
C) ATP hydrolysis at the myosin tail
D) Sodium influx into the sarcoplasmic reticulum
Calcium binds to troponin, causing tropomyosin to move and expose
actin binding sites for myosin.
,7. Which enzyme catalyzes the first step of the citric acid cycle?
A) Succinate dehydrogenase
B) Citrate synthase
C) Pyruvate kinase
D) Hexokinase
Citrate synthase catalyzes the condensation of acetyl-CoA and
oxaloacetate to form citrate.
8. The molecule that carries amino acids to the ribosome during
translation is:
A) mRNA
B) tRNA
C) rRNA
D) snRNA
tRNA has an anticodon complementary to mRNA codons and carries
the corresponding amino acid to the ribosome.
9. The main structural component of cell membranes is:
A) Glycogen
B) Nucleic acids
C) Phospholipids
D) Steroid hormones
Phospholipids form the lipid bilayer, providing structure and selective
permeability for cell membranes.
10. Which of the following is a primary function of the smooth
endoplasmic reticulum?
, A) Protein synthesis
B) Lipid synthesis and detoxification
C) ATP production
D) DNA replication
The smooth ER synthesizes lipids and detoxifies certain chemicals,
unlike the rough ER, which synthesizes proteins.
11. Which of the following enzymes breaks down starch into
maltose?
A) Pepsin
B) Amylase
C) Lipase
D) Lactase
Amylase hydrolyzes starch (a polysaccharide) into maltose (a
disaccharide).
12. Which organ secretes insulin?
A) Liver
B) Adrenal gland
C) Pancreas
D) Thyroid
Beta cells of the pancreas produce insulin, which lowers blood
glucose levels.
13. Which type of RNA carries the genetic information from DNA to
the ribosome?
A) tRNA
B) rRNA
Foundations Exam Questions And Correct
Answers (Verified Answers) Plus Rationales
2025/2026 Q&A | Instant Download Pdf
1. Which organelle is primarily responsible for ATP production in
eukaryotic cells?
A) Nucleus
B) Golgi apparatus
C) Mitochondrion
D) Lysosome
The mitochondrion produces ATP via oxidative phosphorylation,
which is the primary energy currency for the cell.
2. Which of the following macromolecules contains nitrogen in its
structure?
A) Lipids
B) Proteins
C) Carbohydrates
D) Triglycerides
Proteins are composed of amino acids, which contain nitrogen in
their amino groups.
3. During glycolysis, one molecule of glucose is converted into:
A) Two molecules of pyruvate
B) Two molecules of pyruvate
C) Four molecules of ATP only
D) Lactic acid
,Glycolysis splits glucose (6C) into two pyruvate molecules (3C each),
producing a net of 2 ATP.
4. The functional unit of the kidney responsible for filtration is the:
A) Ureter
B) Nephron
C) Glomerulus only
D) Collecting duct
The nephron is the structural and functional unit of the kidney,
containing the glomerulus and tubules for filtration and reabsorption.
5. Which blood type is considered the universal donor?
A) AB+
B) O+
C) O-
D) AB-
O- blood lacks A, B, and Rh antigens, making it compatible with all
recipient blood types.
6. In skeletal muscle, contraction is initiated by:
A) Calcium binding to tropomyosin
B) Calcium binding to troponin
C) ATP hydrolysis at the myosin tail
D) Sodium influx into the sarcoplasmic reticulum
Calcium binds to troponin, causing tropomyosin to move and expose
actin binding sites for myosin.
,7. Which enzyme catalyzes the first step of the citric acid cycle?
A) Succinate dehydrogenase
B) Citrate synthase
C) Pyruvate kinase
D) Hexokinase
Citrate synthase catalyzes the condensation of acetyl-CoA and
oxaloacetate to form citrate.
8. The molecule that carries amino acids to the ribosome during
translation is:
A) mRNA
B) tRNA
C) rRNA
D) snRNA
tRNA has an anticodon complementary to mRNA codons and carries
the corresponding amino acid to the ribosome.
9. The main structural component of cell membranes is:
A) Glycogen
B) Nucleic acids
C) Phospholipids
D) Steroid hormones
Phospholipids form the lipid bilayer, providing structure and selective
permeability for cell membranes.
10. Which of the following is a primary function of the smooth
endoplasmic reticulum?
, A) Protein synthesis
B) Lipid synthesis and detoxification
C) ATP production
D) DNA replication
The smooth ER synthesizes lipids and detoxifies certain chemicals,
unlike the rough ER, which synthesizes proteins.
11. Which of the following enzymes breaks down starch into
maltose?
A) Pepsin
B) Amylase
C) Lipase
D) Lactase
Amylase hydrolyzes starch (a polysaccharide) into maltose (a
disaccharide).
12. Which organ secretes insulin?
A) Liver
B) Adrenal gland
C) Pancreas
D) Thyroid
Beta cells of the pancreas produce insulin, which lowers blood
glucose levels.
13. Which type of RNA carries the genetic information from DNA to
the ribosome?
A) tRNA
B) rRNA
