WGU C785 BIOCHEMISTRY FINAL
EXAM PRACTICE 2026 QUESTIONS AND
ANSWERS
1. Which amino acid is most likely to be found buried in the hydrophobic core of a globular
protein?
A. Phenylalanine
B. Glutamate
C. Lysine
D. Serine
Answer: A
Conceptual Explanation: Phenylalanine has a non-polar, hydrophobic side chain, making
it more likely to be found in the interior of a protein away from water.
2. How does a competitive inhibitor affect enzyme kinetics?
A. Increases Vmax and decreases Km
B. Vmax remains unchanged and Km increases
C. Decreases Vmax and Km remains unchanged
D. Both Vmax and Km decrease
,Answer: B
Conceptual Explanation: Competitive inhibitors compete with the substrate for the active
site, requiring more substrate to reach half-maximal velocity (increasing Km), but the
maximum velocity (Vmax) remains achievable at high substrate concentrations.
3. Which level of protein structure is characterized by alpha-helices and beta-pleated sheets?
A. Secondary
B. Primary
C. Tertiary
D. Quaternary
Answer: A
Conceptual Explanation: Secondary structure refers to local folded structures that form
within a polypeptide due to interactions between atoms of the backbone (hydrogen
bonding).
4. What is the primary physiological function of Myoglobin?
A. Transport of oxygen in the blood
B. Transport of carbon dioxide
C. Buffer for blood pH
D. Storage of oxygen in muscle tissue
Answer: D
, Conceptual Explanation: Myoglobin has a high affinity for oxygen and serves as an oxygen
storage unit in muscle cells, unlike hemoglobin which transports oxygen through the blood.
5. Which molecule acts as a high-energy electron carrier in both Glycolysis and the Citric Acid
Cycle?
A. FADH2
B. NADH
C. ATP
D. NADPH
Answer: B
Conceptual Explanation: NADH is produced in both glycolysis and the citric acid cycle to
carry electrons to the electron transport chain.
6. In DNA replication, which enzyme is responsible for unwinding the double helix?
A. Helicase
B. Ligase
C. DNA Polymerase III
D. Primase
Answer: A
Conceptual Explanation: Helicase breaks the hydrogen bonds between the two strands of
the DNA molecule to unzip the helix.
EXAM PRACTICE 2026 QUESTIONS AND
ANSWERS
1. Which amino acid is most likely to be found buried in the hydrophobic core of a globular
protein?
A. Phenylalanine
B. Glutamate
C. Lysine
D. Serine
Answer: A
Conceptual Explanation: Phenylalanine has a non-polar, hydrophobic side chain, making
it more likely to be found in the interior of a protein away from water.
2. How does a competitive inhibitor affect enzyme kinetics?
A. Increases Vmax and decreases Km
B. Vmax remains unchanged and Km increases
C. Decreases Vmax and Km remains unchanged
D. Both Vmax and Km decrease
,Answer: B
Conceptual Explanation: Competitive inhibitors compete with the substrate for the active
site, requiring more substrate to reach half-maximal velocity (increasing Km), but the
maximum velocity (Vmax) remains achievable at high substrate concentrations.
3. Which level of protein structure is characterized by alpha-helices and beta-pleated sheets?
A. Secondary
B. Primary
C. Tertiary
D. Quaternary
Answer: A
Conceptual Explanation: Secondary structure refers to local folded structures that form
within a polypeptide due to interactions between atoms of the backbone (hydrogen
bonding).
4. What is the primary physiological function of Myoglobin?
A. Transport of oxygen in the blood
B. Transport of carbon dioxide
C. Buffer for blood pH
D. Storage of oxygen in muscle tissue
Answer: D
, Conceptual Explanation: Myoglobin has a high affinity for oxygen and serves as an oxygen
storage unit in muscle cells, unlike hemoglobin which transports oxygen through the blood.
5. Which molecule acts as a high-energy electron carrier in both Glycolysis and the Citric Acid
Cycle?
A. FADH2
B. NADH
C. ATP
D. NADPH
Answer: B
Conceptual Explanation: NADH is produced in both glycolysis and the citric acid cycle to
carry electrons to the electron transport chain.
6. In DNA replication, which enzyme is responsible for unwinding the double helix?
A. Helicase
B. Ligase
C. DNA Polymerase III
D. Primase
Answer: A
Conceptual Explanation: Helicase breaks the hydrogen bonds between the two strands of
the DNA molecule to unzip the helix.
