WGU C785 BIOCHEMISTRY FINAL
EXAM 2026 QUESTIONS AND ANSWERS
1. Which of the following describes the secondary structure of a protein?
A. The local folding of the polypeptide backbone into alpha-helices or beta-sheets.
B. The sequence of amino acids joined by peptide bonds.
C. The overall three-dimensional shape of a single polypeptide chain.
D. The arrangement of multiple polypeptide subunits into a functional complex.
Answer: A
Conceptual Explanation: Secondary structure refers to local folded structures like alpha-
helices and beta-pleated sheets, stabilized by hydrogen bonds between the peptide
backbone components.
2. In DNA replication, which enzyme is responsible for unwinding the double helix?
A. Helicase
B. DNA Ligase
C. DNA Polymerase III
D. Primase
,Answer: A
Conceptual Explanation: Helicase breaks the hydrogen bonds between the two strands of
the DNA double helix, allowing replication to proceed.
3. Which molecule serves as the final electron acceptor in the electron transport chain during
aerobic respiration?
A. NADH
B. FADH2
C. Oxygen
D. Water
Answer: C
Conceptual Explanation: Oxygen acts as the final electron acceptor at the end of the ETC,
where it combines with protons and electrons to form water.
4. How does a competitive inhibitor affect the kinetic parameters of an enzyme-catalyzed
reaction?
A. Increases Vmax and decreases Km.
B. Decreases Vmax and keeps Km unchanged.
C. Decreases both Vmax and Km.
D. Increases Km and keeps Vmax unchanged.
Answer: D
, Conceptual Explanation: Competitive inhibitors compete for the active site, requiring
more substrate to reach 1/2 Vmax (increasing Km), but Vmax remains achievable at high
substrate concentrations.
5. Which of the following amino acids is most likely to be found in the hydrophobic core of a
globular protein?
A. Lysine
B. Glutamate
C. Serine
D. Isoleucine
Answer: D
Conceptual Explanation: Isoleucine has a non-polar side chain, making it hydrophobic
and likely to be buried away from the aqueous environment in the core of a protein.
6. What is the primary role of the Pentose Phosphate Pathway?
A. Production of ATP through oxidative phosphorylation.
B. Synthesis of ketone bodies during starvation.
C. Breakdown of glycogen into glucose units.
D. Generation of NADPH and pentose sugars like ribose-5-phosphate.
Answer: D
EXAM 2026 QUESTIONS AND ANSWERS
1. Which of the following describes the secondary structure of a protein?
A. The local folding of the polypeptide backbone into alpha-helices or beta-sheets.
B. The sequence of amino acids joined by peptide bonds.
C. The overall three-dimensional shape of a single polypeptide chain.
D. The arrangement of multiple polypeptide subunits into a functional complex.
Answer: A
Conceptual Explanation: Secondary structure refers to local folded structures like alpha-
helices and beta-pleated sheets, stabilized by hydrogen bonds between the peptide
backbone components.
2. In DNA replication, which enzyme is responsible for unwinding the double helix?
A. Helicase
B. DNA Ligase
C. DNA Polymerase III
D. Primase
,Answer: A
Conceptual Explanation: Helicase breaks the hydrogen bonds between the two strands of
the DNA double helix, allowing replication to proceed.
3. Which molecule serves as the final electron acceptor in the electron transport chain during
aerobic respiration?
A. NADH
B. FADH2
C. Oxygen
D. Water
Answer: C
Conceptual Explanation: Oxygen acts as the final electron acceptor at the end of the ETC,
where it combines with protons and electrons to form water.
4. How does a competitive inhibitor affect the kinetic parameters of an enzyme-catalyzed
reaction?
A. Increases Vmax and decreases Km.
B. Decreases Vmax and keeps Km unchanged.
C. Decreases both Vmax and Km.
D. Increases Km and keeps Vmax unchanged.
Answer: D
, Conceptual Explanation: Competitive inhibitors compete for the active site, requiring
more substrate to reach 1/2 Vmax (increasing Km), but Vmax remains achievable at high
substrate concentrations.
5. Which of the following amino acids is most likely to be found in the hydrophobic core of a
globular protein?
A. Lysine
B. Glutamate
C. Serine
D. Isoleucine
Answer: D
Conceptual Explanation: Isoleucine has a non-polar side chain, making it hydrophobic
and likely to be buried away from the aqueous environment in the core of a protein.
6. What is the primary role of the Pentose Phosphate Pathway?
A. Production of ATP through oxidative phosphorylation.
B. Synthesis of ketone bodies during starvation.
C. Breakdown of glycogen into glucose units.
D. Generation of NADPH and pentose sugars like ribose-5-phosphate.
Answer: D
